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• How do i implement a message box in a Cocoa application?

  - by mikede

  I have implemented delete functionality in cocoa application now i want to show one meesage box when user click on delete button.

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• MEF C# Service - DLL Updating

  - by connerb

  Currently, I have a C# service that runs off of many .dll's and has modules/plugins that it imports at startup. I would like to create an update system that basically stops the service, deletes any files it is told to delete (old versions), downloads new versions from a server, and starts the service. I believe I have coded this right except for the delete part, because as long as I am not overwriting anything, the file will download. If I try to overwrite something, it won't work, which is why I am trying to delete it before hand. However, when I do File.Delete() to the path that I want to do, it gives me access to the path is denied. Here is my code: new Thread(new ThreadStart(() => { ServiceController controller = new ServiceController("client"); controller.Stop(); controller.WaitForStatus(ServiceControllerStatus.Stopped); try { if (um.FilesUpdated != null) { foreach (FilesUpdated file in um.FilesUpdated) { if (file.OldFile != null) { File.Delete(Path.Combine(Utility.AssemblyDirectory, file.OldFile)); } if (file.NewFile != null) { wc.DownloadFile(cs.UpdateUrl + "/updates/client/" + file.NewFile, Path.Combine(Utility.AssemblyDirectory, file.NewFile)); } } } if (um.ModulesUpdated != null) { foreach (ModulesUpdated module in um.ModulesUpdated) { if (module.OldModule != null) { File.Delete(Path.Combine(cs.ModulePath, module.OldModule)); } if (module.NewModule != null) { wc.DownloadFile(cs.UpdateUrl + "/updates/client/modules/" + module.NewModule, Path.Combine(cs.ModulePath, module.NewModule)); } } } } catch (Exception ex) { Logger.log(ex); } controller.Start(); })).Start(); I believe it is because the files are in use, but I can't seem to unload them. I though stopping the service would work, but apparently not. I have also checked the files and they are not read-only (but the folder is, which is located in Program Files, however I couldn't seem to get it to not be read-only programmatically or manually). The service is also being run as an administrator (NT AUTHORITY\SYSTEM). I've read about unloading the AppDomain but AppDomain.Unload(AppDomain.CurrentDomain); returned an exception as well. Not too sure even if this is a problem with MEF or my program just not having the correct permissions...I would assume that it's mainly because the file is in use.

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• how to create following Java applicatin? [on hold]

  - by Tushar Bichwe

  Write a JAVA program which performs the following listed operations: A. Create a package named MyEmpPackage which consists of following classes A class named Employee which stores information like the Emp number, first name, middle name, last name, address, designation and salary. The class should also contain appropriate get and set methods. 05 A class named AddEmployeeFrame which displays a frame consisting of appropriate controls to enter the details of a Employee and store these details in the Employee class object. The frame should also have three buttons with the caption as “Add Record” and “Delete Record” and “Exit”. 10 A class named MyCustomListener which should work as a user – defined event listener to handle required events as mentioned in following points. 05 B When the “Add Record” button is clicked, the dialog box should be appeared with asking the user “Do you really want to add record in the file”. If the user selects Yes than the record should be saved in the file. 10 When the “Exit” button is clicked, the frame should be closed. 10 [Note: Use the MyCustomListener class only to handle the appropriate events] C The “Delete Record” button should open a new frame which should take input of delete criteria using a radio button. The radio button should provide facility to delete on basis of first name, middle name or last name. 10 The new frame should also have a text box to input the delete criteria value. 10 The record should be deleted from the file and a message dialog should appear with the message that “Record is successfully Deleted”. 10 [Note: Use the MyCustomListener class only to handle the appropriate events] D Provide proper error messages and perform appropriate exceptions where ever required in all the classes 10

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• What's the safest way to remove data from mysql? (PHP/Mysql)

  - by ggfan

  I want to allow users as well as me(the admin) to delete data in mysql. I used to have remove.php that would get $_GETs from whatever that needed to be deleted such as... remove.php?action=post&posting_id=2. But I learned that anyone can simply abuse it and delete all my data. So what's the safest way for users and me to delete information without getting all crazy and hard? I am only a beginner :) I'm not sure if I can use POSTs because there is no forms and the data isn't changing. Is sessions good? Or would there be too many with postings, user information, comments, etc. Ex: James wants to delete one of his postings(it is posting_id=5). So he clicks the remove link and that takes him to remove.php?action=post&posting_id=5.

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• Entity Framework version 1- Brief Synopsis and Tips &ndash; Part 1

  - by Rohit Gupta

  To Do Eager loading use Projections (for e.g. from c in context.Contacts select c, c.Addresses)  or use Include Query Builder Methods (Include(“Addresses”)) If there is multi-level hierarchical Data then to eager load all the relationships use Include Query Builder methods like customers.Include("Order.OrderDetail") to include Order and OrderDetail collections or use customers.Include("Order.OrderDetail.Location") to include all Order, OrderDetail and location collections with a single include statement =========================================================================== If the query uses Joins then Include() Query Builder method will be ignored, use Nested Queries instead If the query does projections then Include() Query Builder method will be ignored Use Address.ContactReference.Load() OR Contact.Addresses.Load() if you need to Deferred Load Specific Entity – This will result in extra round trips to the database ObjectQuery<> cannot return anonymous types... it will return a ObjectQuery<DBDataRecord> Only Include method can be added to Linq Query Methods Any Linq Query method can be added to Query Builder methods. If you need to append a Query Builder Method (other than Include) after a LINQ method  then cast the IQueryable<Contact> to ObjectQuery<Contact> and then append the Query Builder method to it =========================================================================== Query Builder methods are Select, Where, Include Methods which use Entity SQL as parameters e.g. "it.StartDate, it.EndDate" When Query Builder methods do projection then they return ObjectQuery<DBDataRecord>, thus to iterate over this collection use contact.Item[“Name”].ToString() When Linq To Entities methods do projection, they return collection of anonymous types --- thus the collection is strongly typed and supports Intellisense EF Object Context can track changes only on Entities, not on Anonymous types. If you use a Defining Query for a EntitySet then the EntitySet becomes readonly since a Defining Query is the same as a View (which is treated as a ReadOnly by default). However if you want to use this EntitySet for insert/update/deletes then we need to map stored procs (as created in the DB) to the insert/update/delete functions of the Entity in the Designer You can use either Execute method or ToList() method to bind data to datasources/bindingsources If you use the Execute Method then remember that you can traverse through the ObjectResult<> collection (returned by Execute) only ONCE. In WPF use ObservableCollection to bind to data sources , for keeping track of changes and letting EF send updates to the DB automatically. Use Extension Methods to add logic to Entities. For e.g. create extension methods for the EntityObject class. Create a method in ObjectContext Partial class and pass the entity as a parameter, then call this method as desired from within each entity. ================================================================ DefiningQueries and Stored Procedures: For Custom Entities, one can use DefiningQuery or Stored Procedures. Thus the Custom Entity Collection will be populated using the DefiningQuery (of the EntitySet) or the Sproc. If you use Sproc to populate the EntityCollection then the query execution is immediate and this execution happens on the Server side and any filters applied will be applied in the Client App. If we use a DefiningQuery then these queries are composable, meaning the filters (if applied to the entityset) will all be sent together as a single query to the DB, returning only filtered results. If the sproc returns results that cannot be mapped to existing entity, then we first create the Entity/EntitySet in the CSDL using Designer, then create a dummy Entity/EntitySet using XML in the SSDL. When creating a EntitySet in the SSDL for this dummy entity, use a TSQL that does not return any results, but does return the relevant columns e.g. select ContactID, FirstName, LastName from dbo.Contact where 1=2 Also insure that the Entity created in the SSDL uses the SQL DataTypes and not .NET DataTypes. If you are unable to open the EDMX file in the designer then note the Errors ... they will give precise info on what is wrong. The Thrid option is to simply create a Native Query in the SSDL using <Function Name="PaymentsforContact" IsComposable="false">   <CommandText>SELECT ActivityId, Activity AS ActivityName, ImagePath, Category FROM dbo.Activities </CommandText></FuncTion> Then map this Function to a existing Entity. This is a quick way to get a custom Entity which is regular Entity with renamed columns or additional columns (which are computed columns). The disadvantage to using this is that It will return all the rows from the Defining query and any filter (if defined) will be applied only at the Client side (after getting all the rows from DB). If you you DefiningQuery instead then we can use that as a Composable Query. The Fourth option (for mapping a READ stored proc results to a non-existent Entity) is to create a View in the Database which returns all the fields that the sproc also returns, then update the Model so that the model contains this View as a Entity. Then map the Read Sproc to this View Entity. The other option would be to simply create the View and remove the sproc altogether. ================================================================ To Execute a SProc that does not return a entity, use a EntityCommand to execute that proc. You cannot call a sproc FunctionImport that does not return Entities From Code, the only way is to use SSDL function calls using EntityCommand.  This changes with EntityFramework Version 4 where you can return Scalar Types, Complex Types, Entities or NonQuery ================================================================ UDF when created as a Function in SSDL, we need to set the Name & IsComposable properties for the Function element. IsComposable is always false for Sprocs, for UDF's set this to true. You cannot call UDF "Function" from within code since you cannot import a UDF Function into the CSDL Model (with Version 1 of EF). only stored procedures can be imported and then mapped to a entity ================================================================ Entity Framework requires properties that are involved in association mappings to be mapped in all of the function mappings for the entity (Insert, Update and Delete). Because Payment has an association to Reservation... hence we need to pass both the paymentId and reservationId to the Delete sproc even though just the paymentId is the PK on the Payment Table. ================================================================ When mapping insert, update and delete procs to a Entity, insure that all the three or none are mapped. Further if you have a base class and derived class in the CSDL, then you must map (ins, upd, del) sprocs to all parent and child entities in the inheritance relationship. Note that this limitation that base and derived entity methods must all must be mapped does not apply when you are mapping Read Stored Procedures.... ================================================================ You can write stored procedures SQL directly into the SSDL by creating a Function element in the SSDL and then once created, you can map this Function to a CSDL Entity directly in the designer during Function Import ================================================================ You can do Entity Splitting such that One Entity maps to multiple tables in the DB. For e.g. the Customer Entity currently derives from Contact Entity...in addition it also references the ContactPersonalInfo Entity. One can copy all properties from the ContactPersonalInfo Entity into the Customer Entity and then Delete the CustomerPersonalInfo entity, finall one needs to map the copied properties to the ContactPersonalInfo Table in Table Mapping (by adding another table (ContactPersonalInfo) to the Table Mapping... this is called Entity Splitting. Thus now when you insert a Customer record, it will automatically create SQL to insert records into the Contact, Customers and ContactPersonalInfo tables even though you have a Single Entity called Customer in the CSDL =================================================================== There is Table by Type Inheritance where another EDM Entity can derive from another EDM entity and absorb the inherted entities properties, for example in the Break Away Geek Adventures EDM, the Customer entity derives (inherits) from the Contact Entity and absorbs all the properties of Contact entity. Thus when you create a Customer Entity in Code and then call context.SaveChanges the Object Context will first create the TSQL to insert into the Contact Table followed by a TSQL to insert into the Customer table =================================================================== Then there is the Table per Hierarchy Inheritance..... where different types are created based on a condition (similar applying a condition to filter a Entity to contain filtered records)... the diference being that the filter condition populates a new Entity Type (derived from the base Entity). In the BreakAway sample the example is Lodging Entity which is a Abstract Entity and Then Resort and NonResort Entities which derive from Lodging Entity and records are filtered based on the value of the Resort Boolean field =================================================================== Then there is Table per Concrete Type Hierarchy where we create a concrete Entity for each table in the database. In the BreakAway sample there is a entity for the Reservation table and another Entity for the OldReservation table even though both the table contain the same number of fields. The OldReservation Entity can then inherit from the Reservation Entity and configure the OldReservation Entity to remove all Scalar Properties from the Entity (since it inherits the properties from Reservation and filters based on ReservationDate field) =================================================================== Complex Types (Complex Properties) Entities in EF can also contain Complex Properties (in addition to Scalar Properties) and these Complex Properties reference a ComplexType (not a EntityType) DropdownList, ListBox, RadioButtonList, CheckboxList, Bulletedlist are examples of List server controls (not data bound controls) these controls cannot use Complex properties during databinding, they need Scalar Properties. So if a Entity contains Complex properties and you need to bind those to list server controls then use projections to return Scalar properties and bind them to the control (the disadvantage is that projected collections are not tracked by the Object Context and hence cannot persist changes to the projected collections bound to controls) ObjectDataSource and EntityDataSource do account for Complex properties and one can bind entities with Complex Properties to Data Source controls and they will be tracked for changes... with no additional plumbing needed to persist changes to these collections bound to controls So DataBound controls like GridView, FormView need to use EntityDataSource or ObjectDataSource as a datasource for entities that contain Complex properties so that changes to the datasource done using the GridView can be persisted to the DB (enabling the controls for updates)....if you cannot use the EntityDataSource you need to flatten the ComplexType Properties using projections With EF Version 4 ComplexTypes are supported by the Designer and can add/remove/compose Complex Types directly using the Designer =================================================================== Conditional Mapping ... is like Table per Hierarchy Inheritance where Entities inherit from a base class and then used conditions to populate the EntitySet (called conditional Mapping). Conditional Mapping has limitations since you can only use =, is null and IS NOT NULL Conditions to do conditional mapping. If you need more operators for filtering/mapping conditionally then use QueryView(or possibly Defining Query) to create a readonly entity. QueryView are readonly by default... the EntitySet created by the QueryView is enabled for change tracking by the ObjectContext, however the ObjectContext cannot create insert/update/delete TSQL statements for these Entities when SaveChanges is called since it is QueryView. One way to get around this limitation is to map stored procedures for the insert/update/delete operations in the Designer. =================================================================== Difference between QueryView and Defining Query : QueryView is defined in the (MSL) Mapping File/section of the EDM XML, whereas the DefiningQuery is defined in the store schema (SSDL). QueryView is written using Entity SQL and is this database agnostic and can be used against any database/Data Layer. DefiningQuery is written using Database Lanaguage i.e. TSQL or PSQL thus you have more control =================================================================== Performance: Lazy loading is deferred loading done automatically. lazy loading is supported with EF version4 and is on by default. If you need to turn it off then use context.ContextOptions.lazyLoadingEnabled = false To improve Performance consider PreCompiling the ObjectQuery using the CompiledQuery.Compile method

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• Simple Branching and Merging with SVN

  Its a good idea not to do too much work without checking something into source control.  By too much work I mean typically on the order of a couple of hours at most, and certainly its a good practice to check in anything you have before you leave the office for the day.  But what if your changes break the build (on the build server you do have a build server dont you?) or would cause problems for others on your team if they get the latest code?  The solution with Subversion is branching and merging (incidentally, if youre using Microsoft Visual Studio Team System, you can shelve your changes and share shelvesets with others, which accomplishes many of the same things as branching and merging, but is a bit simpler to do). Getting Started Im going to assume you have Subversion installed along with the nearly ubiquitous client, TortoiseSVN.  See my previous post on installing SVN server if you want to get it set up real quick (you can put it on your workstation/laptop just to learn how it works easily enough). Overview When you know you are going to be working on something that you wont be able to check in quickly, its a good idea to start a branch.  Its also perfectly fine to create the branch after-the-fact (have you ever started something thinking it would be an hour and 4 hours later realized you were nowhere near done?).  In any event, the first thing you need to do is create a branch.  A branch is simply a copy of the current trunk (a typical subversion setup has root directories called trunk, tags, and branches its a good idea to keep this and to put your branches in the branches folder).  Once you have a new branch, you need to switch your working copy so that it is bound to your branch.  As you work,  you may want to merge in changes that are happening in the trunk to your branch, and ultimately when you are done youll want to merge your branch back into the trunk.  When done, you can delete your branch (or not, but it may add clutter).  To sum up: Create a new branch Switch your local working copy to the new branch Develop in the branch (commit changes, etc.) Merge changes from trunk into your branch Merge changes from branch into trunk Delete the branch Create a new branch From the root of your repository, right-click and select TortoiseSVN > Branch/tag as shown at right (click to enlarge).  This will bring up the Copy (Branch / Tag) interface.  By default the From WC at URL: should be pointing at the trunk of your repository.  I recommend (after ensuring that you have the latest version) that you choose to make the copy from the HEAD revision in the repository (the first radio button).  In the To URL: textbox, you should change the URL from /trunk to /branches/NAME_OF_BRANCH.  You can name the branch anything you like, but its often useful to give it your name (if its just for your use) or some useful information (such as a datestamp or a bug/issue ID from that it relates to, or perhaps just the name of the feature you are adding. When youre done with that, enter in a log message for your new branch.  If you want to immediately switch your local working copy to the new branch/tag, check the box at the bottom of the dialog (Switch working copy to new branch/tag).  You can see an example at right. Assuming everything works, you should very quickly see a window telling you the Copy finished, like the one shown below: Switch Local Working Copy to New Branch If you followed the instructions above and checked the box when you created your branch, you dont need to do this step.  However, if you have a branch that already exists and you would like to switch over to working on it, you can do so by using the Switch command.  Youll find it in the explorer context menu under TortoiseSVN > Switch: This brings up a dialog that shows you your current binding, and lets you enter in a new URL to switch to: In the screenshot above, you can see that Im currently bound to a branch, and so I could switch back to the trunk or to another branch.  If youre not sure what to enter here, you can click the [] next to the URL textbox to explore your repository and find the appropriate root URL to use.  Also, the dropdown will show you URLs that might be a good fit (such as the trunk of the current repository). Develop in the Branch Once you have created a branch and switched your working copy to use it,  you can make changes and Commit them as usual.  Your commits are now going into the branch, so they wont impact other users or the build server that are working off of the trunk (or their own branches).  In theory you can keep on doing this forever, but practically its a good idea to periodically merge the trunk into your branch, and/or keep your branches short-lived and merge them back into the trunk before they get too far out of sync. Merge Changes from Trunk into your Branch Once you have been working in a branch for a little while, change to the trunk will have occurred that youll want to merge into your branch.  Its much safer and easier to integrate changes in small increments than to wait for weeks or months and then try to merge in two very different codebases.  To perform the merge, simply go to the root of your branch working copy and right click, select TortoiseSVN->Merge.  Youll be presented with this dialog: In this case you want to leave the default setting, Merge a range of revisions.  Click Next.  Now choose the URL to merge from.  You should select the trunk of your current repository (which should be in the dropdownlist, or you can click the [] to browse your repository for the correct URL).  You can leave everything else blank since you want to merge everything: Click Next.  Again you can leave the default settings.  If you want to do something more granular than everything in the trunk, you can select a different Merge depth, to include merging just one item in the tree.  You can also perform a Test merge to see what changes will take place before you click Merge (which is often a good idea).  Heres what the dialog should look like before you click Merge: After clicking Merge (or Test merge) you should see a confirmation like this (it will say Test Only in the title if you click Test merge): Now you should build your solution, run all of your tests, and verify that your branch still works the way it should, given the updates that youve just integrated from the trunk.  Once everything works, Commit your changes, and then continue with your work on the branch.  Note that until you commit, nothing has actually changed in your branch on the server.  Other team members who may also be working in this branch wont be impacted, etc.  The Merge is purely a client-side operation until you perform a Commit. In a more real-world scenario, you may have conflicts.  When you do, youll be presented with a dialog like this one: Its up to you which option you want to go with.  The more frequently you Merge, the fewer of these youll have to deal with.  Also, be very sure that youre merging the right folders together.  If you try and merge your trunk with some subfolder in your branchs structure, youll end up with all kinds of conflicts and problems.  Fortunately, theyre only on your working copy (unless you commit them!) but if you see something like that, be sure to doublecheck your URL and your local file location. Merge Your Branch Back Into Trunk When youre done working in your branch, its time to pull it back into the trunk.  The first thing you should do is follow the previous steps instructions for merging the latest from the trunk into your branch.  This lets you ensure that what you have in your branch works correctly with the current trunk.  Once youve done that and committed your changes to your branch, youre ready to proceed with this step. Once youre confident your branch is good to go, you should go to its root folder and select TortoiseSVN->Merge (as above) from the explorer right-click menu.  This time, select Reintegrate a branch as shown below: Click Next.  Youll want it to merge with the trunk, which should be the default: Click Next. Leave the default settings: Click Test merge to see a test, and then if all looks good, click Merge.  Note that if you havent checked in your working copy changes, youll see something like this: If on the other hand things are successful: After this step, its likely you are finished working in your branch.  Dont forget to use the ToroiseSVN->Switch command to change your working copy back to the trunk. Delete the Branch You dont have to delete the branch, but over time your branches area of your repository will get cluttered, and in any event if theyre not actively being worked on the branches are just taking up space and adding to later confusion.  Keeping your branches limited to things youre actively working on is simply a good habit to get into, just like making sure your codebase itself remains tidy and not filled with old commented out bits of code. To delete the branch after youre finished with it, the simplest thing to do is choose TortoiseSVN->Repo Browser.  From there, assuming you did this from your branch, it should already be highlighted.  In any event, navigate to your branch in the treeview on the left, and then right-click and select Delete.  Enter a log message if youd like: Click OK, and its gone.  Dont be too afraid of this, though.  You can still get to the files by viewing the log for branches, and selecting a previous revision (anything before the delete action): If for some reason you needed something that was previously in this branch, you could easily get back to any changeset you checked in, so you should have absolutely no fear when it comes to deleting branches youre done with.   Resources If youre using Eclipse, theres a nice write-up of the steps required by Zach Cox that I found helpful here. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Metro: Creating an IndexedDbDataSource for WinJS

  - by Stephen.Walther

  The goal of this blog entry is to describe how you can create custom data sources which you can use with the controls in the WinJS library. In particular, I explain how you can create an IndexedDbDataSource which you can use to store and retrieve data from an IndexedDB database. If you want to skip ahead, and ignore all of the fascinating content in-between, I’ve included the complete code for the IndexedDbDataSource at the very bottom of this blog entry. What is IndexedDB? IndexedDB is a database in the browser. You can use the IndexedDB API with all modern browsers including Firefox, Chrome, and Internet Explorer 10. And, of course, you can use IndexedDB with Metro style apps written with JavaScript. If you need to persist data in a Metro style app written with JavaScript then IndexedDB is a good option. Each Metro app can only interact with its own IndexedDB databases. And, IndexedDB provides you with transactions, indices, and cursors – the elements of any modern database. An IndexedDB database might be different than the type of database that you normally use. An IndexedDB database is an object-oriented database and not a relational database. Instead of storing data in tables, you store data in object stores. You store JavaScript objects in an IndexedDB object store. You create new IndexedDB object stores by handling the upgradeneeded event when you attempt to open a connection to an IndexedDB database. For example, here’s how you would both open a connection to an existing database named TasksDB and create the TasksDB database when it does not already exist: var reqOpen = window.indexedDB.open(“TasksDB”, 2); reqOpen.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); }; reqOpen.onsuccess = function () { var db = reqOpen.result; // Do something with db }; When you call window.indexedDB.open(), and the database does not already exist, then the upgradeneeded event is raised. In the code above, the upgradeneeded handler creates a new object store named tasks. The new object store has an auto-increment column named id which acts as the primary key column. If the database already exists with the right version, and you call window.indexedDB.open(), then the success event is raised. At that point, you have an open connection to the existing database and you can start doing something with the database. You use asynchronous methods to interact with an IndexedDB database. For example, the following code illustrates how you would add a new object to the tasks object store: var transaction = db.transaction(“tasks”, “readwrite”); var reqAdd = transaction.objectStore(“tasks”).add({ name: “Feed the dog” }); reqAdd.onsuccess = function() { // Tasks added successfully }; The code above creates a new database transaction, adds a new task to the tasks object store, and handles the success event. If the new task gets added successfully then the success event is raised. Creating a WinJS IndexedDbDataSource The most powerful control in the WinJS library is the ListView control. This is the control that you use to display a collection of items. If you want to display data with a ListView control, you need to bind the control to a data source. The WinJS library includes two objects which you can use as a data source: the List object and the StorageDataSource object. The List object enables you to represent a JavaScript array as a data source and the StorageDataSource enables you to represent the file system as a data source. If you want to bind an IndexedDB database to a ListView then you have a choice. You can either dump the items from the IndexedDB database into a List object or you can create a custom data source. I explored the first approach in a previous blog entry. In this blog entry, I explain how you can create a custom IndexedDB data source. Implementing the IListDataSource Interface You create a custom data source by implementing the IListDataSource interface. This interface contains the contract for the methods which the ListView needs to interact with a data source. The easiest way to implement the IListDataSource interface is to derive a new object from the base VirtualizedDataSource object. The VirtualizedDataSource object requires a data adapter which implements the IListDataAdapter interface. Yes, because of the number of objects involved, this is a little confusing. Your code ends up looking something like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); The code above is used to create a new class named IndexedDbDataSource which derives from the base VirtualizedDataSource class. In the constructor for the new class, the base class _baseDataSourceConstructor() method is called. A data adapter is passed to the _baseDataSourceConstructor() method. The code above creates a new method exposed by the IndexedDbDataSource named nuke(). The nuke() method deletes all of the objects from an object store. The code above also overrides a method named remove(). Our derived remove() method accepts any type of key and removes the matching item from the object store. Almost all of the work of creating a custom data source goes into building the data adapter class. The data adapter class implements the IListDataAdapter interface which contains the following methods: · change() · getCount() · insertAfter() · insertAtEnd() · insertAtStart() · insertBefore() · itemsFromDescription() · itemsFromEnd() · itemsFromIndex() · itemsFromKey() · itemsFromStart() · itemSignature() · moveAfter() · moveBefore() · moveToEnd() · moveToStart() · remove() · setNotificationHandler() · compareByIdentity Fortunately, you are not required to implement all of these methods. You only need to implement the methods that you actually need. In the case of the IndexedDbDataSource, I implemented the getCount(), itemsFromIndex(), insertAtEnd(), and remove() methods. If you are creating a read-only data source then you really only need to implement the getCount() and itemsFromIndex() methods. Implementing the getCount() Method The getCount() method returns the total number of items from the data source. So, if you are storing 10,000 items in an object store then this method would return the value 10,000. Here’s how I implemented the getCount() method: getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); } The first thing that you should notice is that the getCount() method returns a WinJS promise. This is a requirement. The getCount() method is asynchronous which is a good thing because all of the IndexedDB methods (at least the methods implemented in current browsers) are also asynchronous. The code above retrieves an object store and then uses the IndexedDB count() method to get a count of the items in the object store. The value is returned from the promise by calling complete(). Implementing the itemsFromIndex method When a ListView displays its items, it calls the itemsFromIndex() method. By default, it calls this method multiple times to get different ranges of items. Three parameters are passed to the itemsFromIndex() method: the requestIndex, countBefore, and countAfter parameters. The requestIndex indicates the index of the item from the database to show. The countBefore and countAfter parameters represent hints. These are integer values which represent the number of items before and after the requestIndex to retrieve. Again, these are only hints and you can return as many items before and after the request index as you please. Here’s how I implemented the itemsFromIndex method: itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); } In the code above, a cursor is used to iterate through the objects in an object store. You fetch the next item in the cursor by calling either the cursor.continue() or cursor.advance() method. The continue() method moves forward by one object and the advance() method moves forward a specified number of objects. Each time you call continue() or advance(), the success event is raised again. If the cursor is null then you know that you have reached the end of the cursor and you can return the results. Some things to be careful about here. First, the return value from the itemsFromIndex() method must implement the IFetchResult interface. In particular, you must return an object which has an items, offset, and totalCount property. Second, each item in the items array must implement the IListItem interface. Each item should have a key and a data property. Implementing the insertAtEnd() Method When creating the IndexedDbDataSource, I wanted to go beyond creating a simple read-only data source and support inserting and deleting objects. If you want to support adding new items with your data source then you need to implement the insertAtEnd() method. Here’s how I implemented the insertAtEnd() method for the IndexedDbDataSource: insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); } When implementing the insertAtEnd() method, you need to be careful to return an object which implements the IItem interface. In particular, you should return an object that has a key and a data property. The key must be a string and it uniquely represents the new item added to the data source. The value of the data property represents the new item itself. Implementing the remove() Method Finally, you use the remove() method to remove an item from the data source. You call the remove() method with the key of the item which you want to remove. Implementing the remove() method in the case of the IndexedDbDataSource was a little tricky. The problem is that an IndexedDB object store uses an integer key and the VirtualizedDataSource requires a string key. For that reason, I needed to override the remove() method in the derived IndexedDbDataSource class like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); When you call remove(), you end up calling a method of the IndexedDbDataAdapter named removeInternal() . Here’s what the removeInternal() method looks like: setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); } The removeInternal() method calls the IndexedDB delete() method to delete an item from the object store. If the item is deleted successfully then the _notificationHandler.remove() method is called. Because we are not implementing the standard IListDataAdapter remove() method, we need to notify the data source (and the ListView control bound to the data source) that an item has been removed. The way that you notify the data source is by calling the _notificationHandler.remove() method. Notice that we get the _notificationHandler in the code above by implementing another method in the IListDataAdapter interface: the setNotificationHandler() method. You can raise the following types of notifications using the _notificationHandler: · beginNotifications() · changed() · endNotifications() · inserted() · invalidateAll() · moved() · removed() · reload() These methods are all part of the IListDataNotificationHandler interface in the WinJS library. Implementing the nuke() Method I wanted to implement a method which would remove all of the items from an object store. Therefore, I created a method named nuke() which calls the IndexedDB clear() method: nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); } Notice that the nuke() method calls the _notificationHandler.reload() method to notify the ListView to reload all of the items from its data source. Because we are implementing a custom method here, we need to use the _notificationHandler to send an update. Using the IndexedDbDataSource To illustrate how you can use the IndexedDbDataSource, I created a simple task list app. You can add new tasks, delete existing tasks, and nuke all of the tasks. You delete an item by selecting an item (swipe or right-click) and clicking the Delete button. Here’s the HTML page which contains the ListView, the form for adding new tasks, and the buttons for deleting and nuking tasks: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>DataSources</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.1.0.RC/css/ui-dark.css" rel="stylesheet" /> <script src="//Microsoft.WinJS.1.0.RC/js/base.js"></script> <script src="//Microsoft.WinJS.1.0.RC/js/ui.js"></script> <!-- DataSources references --> <link href="indexedDb.css" rel="stylesheet" /> <script type="text/javascript" src="indexedDbDataSource.js"></script> <script src="indexedDb.js"></script> </head> <body> <div id="tmplTask" data-win-control="WinJS.Binding.Template"> <div class="taskItem"> Id: <span data-win-bind="innerText:id"></span> <br /><br /> Name: <span data-win-bind="innerText:name"></span> </div> </div> <div id="lvTasks" data-win-control="WinJS.UI.ListView" data-win-options="{ itemTemplate: select('#tmplTask'), selectionMode: 'single' }"></div> <form id="frmAdd"> <fieldset> <legend>Add Task</legend> <label>New Task</label> <input id="inputTaskName" required /> <button>Add</button> </fieldset> </form> <button id="btnNuke">Nuke</button> <button id="btnDelete">Delete</button> </body> </html> And here is the JavaScript code for the TaskList app: /// <reference path="//Microsoft.WinJS.1.0.RC/js/base.js" /> /// <reference path="//Microsoft.WinJS.1.0.RC/js/ui.js" /> function init() { WinJS.UI.processAll().done(function () { var lvTasks = document.getElementById("lvTasks").winControl; // Bind the ListView to its data source var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; // Wire-up Add, Delete, Nuke buttons document.getElementById("frmAdd").addEventListener("submit", function (evt) { evt.preventDefault(); tasksDataSource.beginEdits(); tasksDataSource.insertAtEnd(null, { name: document.getElementById("inputTaskName").value }).done(function (newItem) { tasksDataSource.endEdits(); document.getElementById("frmAdd").reset(); lvTasks.ensureVisible(newItem.index); }); }); document.getElementById("btnDelete").addEventListener("click", function () { if (lvTasks.selection.count() == 1) { lvTasks.selection.getItems().done(function (items) { tasksDataSource.remove(items[0].data.id); }); } }); document.getElementById("btnNuke").addEventListener("click", function () { tasksDataSource.nuke(); }); // This method is called to initialize the IndexedDb database function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } }); } document.addEventListener("DOMContentLoaded", init); The IndexedDbDataSource is created and bound to the ListView control with the following two lines of code: var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; The IndexedDbDataSource is created with four parameters: the name of the database to create, the version of the database to create, the name of the object store to create, and a function which contains code to initialize the new database. The upgrade function creates a new object store named tasks with an auto-increment property named id: function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } The Complete Code for the IndexedDbDataSource Here’s the complete code for the IndexedDbDataSource: (function () { /************************************************ * The IndexedDBDataAdapter enables you to work * with a HTML5 IndexedDB database. *************************************************/ var IndexedDbDataAdapter = WinJS.Class.define( function (dbName, dbVersion, objectStoreName, upgrade, error) { this._dbName = dbName; // database name this._dbVersion = dbVersion; // database version this._objectStoreName = objectStoreName; // object store name this._upgrade = upgrade; // database upgrade script this._error = error || function (evt) { console.log(evt.message); }; }, { /******************************************* * IListDataAdapter Interface Methods ********************************************/ getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); }, itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); }, insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); }, setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, /***************************************** * IndexedDbDataSource Method ******************************************/ removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); }, nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); }, /******************************************* * Private Methods ********************************************/ _ensureDbOpen: function () { var that = this; // Try to get cached Db if (that._cachedDb) { return WinJS.Promise.wrap(that._cachedDb); } // Otherwise, open the database return new WinJS.Promise(function (complete, error, progress) { var reqOpen = window.indexedDB.open(that._dbName, that._dbVersion); reqOpen.onerror = function (evt) { error(); }; reqOpen.onupgradeneeded = function (evt) { that._upgrade(evt); that._notificationHandler.invalidateAll(); }; reqOpen.onsuccess = function () { that._cachedDb = reqOpen.result; complete(that._cachedDb); }; }); }, _getObjectStore: function (type) { type = type || "readonly"; var that = this; return new WinJS.Promise(function (complete, error) { that._ensureDbOpen().then(function (db) { var transaction = db.transaction(that._objectStoreName, type); complete(transaction.objectStore(that._objectStoreName)); }); }); }, _get: function (key) { return new WinJS.Promise(function (complete, error) { that._getObjectStore().done(function (store) { var reqGet = store.get(key); reqGet.onerror = that._error; reqGet.onsuccess = function (item) { complete(item); }; }); }); } } ); var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); WinJS.Namespace.define("DataSources", { IndexedDbDataSource: IndexedDbDataSource }); })(); Summary In this blog post, I provided an overview of how you can create a new data source which you can use with the WinJS library. I described how you can create an IndexedDbDataSource which you can use to bind a ListView control to an IndexedDB database. While describing how you can create a custom data source, I explained how you can implement the IListDataAdapter interface. You also learned how to raise notifications — such as a removed or invalidateAll notification — by taking advantage of the methods of the IListDataNotificationHandler interface.

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• Permissions restoring from Time Machine - Finder copy vs "cp" copy

  - by Ben Challenor

  Note: this question was starting to sprawl so I rewrote it. I have a folder that I'm trying to restore from a Time Machine backup. Using cp -R works fine, but certain folders cannot be restored with either the Time Machine UI or Finder. Other users have reported similar errors and the cp -R workaround was suggested (e.g. Restoring from Time Machine - Permissions Error). But I wanted to understand: Why cp -R works when the Finder and the Time Machine UI do not. Whether I could prevent the errors by changing file permissions before the backup. There do indeed seem to be some permissions that Finder works with and some that it does not. I've narrowed the errors down to folders with the user ben (that's me) and the group wheel. Here's a simplified reproduction. I have four folders with the owner/group combinations I've seen so far: ben ~/Desktop/test $ ls -lea total 16 drwxr-xr-x 7 ben staff 238 27 Nov 14:31 . drwx------+ 17 ben staff 578 27 Nov 14:29 .. 0: group:everyone deny delete -rw-r--r--@ 1 ben staff 6148 27 Nov 14:31 .DS_Store drwxr-xr-x 3 ben staff 102 27 Nov 14:30 ben-staff drwxr-xr-x 3 ben wheel 102 27 Nov 14:30 ben-wheel drwxr-xr-x 3 root admin 102 27 Nov 14:31 root-admin drwxr-xr-x 3 root wheel 102 27 Nov 14:31 root-wheel Each contains a single file called file with the same owner/group: ben ~/Desktop/test $ cd ben-staff ben ~/Desktop/test/ben-staff $ ls -lea total 0 drwxr-xr-x 3 ben staff 102 27 Nov 14:30 . drwxr-xr-x 7 ben staff 238 27 Nov 14:31 .. -rw-r--r-- 1 ben staff 0 27 Nov 14:30 file In the backup, they look like this: ben /Volumes/Deimos/Backups.backupdb/Ben’s MacBook Air/Latest/Macintosh HD/Users/ben/Desktop/test $ ls -leA total 16 -rw-r--r--@ 1 ben staff 6148 27 Nov 14:34 .DS_Store 0: group:everyone deny write,delete,append,writeattr,writeextattr,chown drwxr-xr-x@ 3 ben staff 102 27 Nov 14:51 ben-staff 0: group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown drwxr-xr-x@ 3 ben wheel 102 27 Nov 14:51 ben-wheel 0: group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown drwxr-xr-x@ 3 root admin 102 27 Nov 14:52 root-admin 0: group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown drwxr-xr-x@ 3 root wheel 102 27 Nov 14:52 root-wheel 0: group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown Of these, ben-staff can be restored with Finder without errors. root-wheel and root-admin ask for my password and then restore without errors. But ben-wheel does not prompt for my password and gives the error: The operation can’t be completed because you don’t have permission to access “file”. Interestingly, I can restore the file from this folder by dragging it directly to my local drive (instead of dragging its parent folder), but when I do so its permissions are changed to ben/staff. Here are the permissions after the restore for the three folders that worked correctly, and the file from ben-wheel that was changed to ben/staff. ben ~/Desktop/test-restore $ ls -leA total 16 -rw-r--r--@ 1 ben staff 6148 27 Nov 14:46 .DS_Store drwxr-xr-x 3 ben staff 102 27 Nov 14:30 ben-staff -rw-r--r-- 1 ben staff 0 27 Nov 14:30 file drwxr-xr-x 3 root admin 102 27 Nov 14:31 root-admin drwxr-xr-x 3 root wheel 102 27 Nov 14:31 root-wheel Can anyone explain this behaviour? Why do Finder and the Time Machine UI break with the ben / wheel permissions? And why does cp -R work (even without sudo)?

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• Replace dual-XP installs with single-XP install and repartition drive?

  - by caeious

  Hello, The Current Situation I have a hard drive that currently is split up like so: Primary Partition C: 9.77 GB NTFS Healthy (System) with XP Pro (in Polish) installed Extended Partition D: 39.82 GB NTFS Healthy (Boot) with XP Pro (in English) installed 6.30 GB Free space When I start my comuter I get a black and white Windows Boot Manager dual boot screen with 2 choices both being Microsoft Windows XP. The first choice is the English version of XP and the second choice is the Polish version of XP. Images of my Computer Management window and Dual Boot screen The Mission What I need to do is get rid of the entire extended partition (D: 39.82 GB & 6.30 free space) and just have the one primary C: drive which I assume will be somewheres around 55 GB big. So in the end I just want XP Pro in English running on my C: drive and no black and white boot screen to show up when starting up my laptop. The Question How do I go about successfully completing The Mission with out making my computer a useless pile of silicon, plastic and metal? UPDATE: So I went ahead and tried to follow Neal's suggestion but hit a wall. I got to a Windows XP Pro install screen that had the 3 following options as well as my drive data: To set up Windows XP on the selected item, press Enter To create a partition in the unpartitioned space, press C To delete the selected partition, press D 57232 MB Disk 0 at Id 0 on bus 0 on atapi [MBR] C: Partition1 [NTFS] 10001 MB ( 4642 MB free ) Unpartitioned space 6448 MB D: Partition2 [NTFS] 40774 MB ( 26225 MB free ) Unpartitioned space 8 MB I figured I would go with the first choice ((To set up Windows XP on the selected item, press Enter)) because I just wanted to set up Windows XP on C: Partition1 (which was preselected) so I pressed Enter which brought me to a screen displaying this message: You chose to install Windows XP on a partition that contains another operating system. Installing Windows XP on this partition might cause the other operating system to function improperly. CAUTION: Installing multiple operating systems on a single partition is not recommended. So this leads me to 2 new questions: How do I get rid of the Windows XP (Polish language) install on C: Partition 1 so that I can cleanly and safely install Windows XP (English language) on it? Neal, is this what you meant by me possibly having to delete the partition that the Windows XP (Polish language) install was located on? Since I have the option to delete partitions with the 3rd choice ((To delete the selected partition, press D)), should I do that on this screen or wait until I have Windows XP (English language) safely installed on C: Partition 1? I have to ask these questions because I have read that it is possibly dangerous to delete hard drive partitions. Just being cautious.

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• How to get SQL Railroad Diagrams from MSDN BNF syntax notation.

  - by Phil Factor

  pre {margin-bottom:.0001pt; font-size:8.0pt; font-family:"Courier New"; margin-left: 0cm; margin-right: 0cm; margin-top: 0cm; } On SQL Server Books-On-Line, in the Transact-SQL Reference (database Engine), every SQL Statement has its syntax represented in  ‘Backus–Naur Form’ notation (BNF)  syntax. For a programmer in a hurry, this should be ideal because It is the only quick way to understand and appreciate all the permutations of the syntax. It is a great feature once you get your eye in. It isn’t the only way to get the information;  You can, of course, reverse-engineer an understanding of the syntax from the examples, but your understanding won’t be complete, and you’ll have wasted time doing it. BNF is a good start in representing the syntax:  Oracle and SQLite go one step further, and have proper railroad diagrams for their syntax, which is a far more accessible way of doing it. There are three problems with the BNF on MSDN. Firstly, it is isn’t a standard version of  BNF, but an ancient fork from EBNF, inherited from Sybase. Secondly, it is excruciatingly difficult to understand, and thirdly it has a number of syntactic and semantic errors. The page describing DML triggers, for example, currently has the absurd BNF error that makes it state that all statements in the body of the trigger must be separated by commas.  There are a few other detail problems too. Here is the offending syntax for a DML trigger, pasted from MSDN. Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { sql_statement [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS Clause ]   <method_specifier> ::=  This should, of course, be /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { {sql_statement [ ; ]} [ ...n ] | EXTERNAL NAME <method_specifier> [ ; ] }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS CLAUSE ]   <method_specifier> ::=     assembly_name.class_name.method_name I’d love to tell Microsoft when I spot errors like this so they can correct them but I can’t. Obviously, there is a mechanism on MSDN to get errors corrected by using comments, but that doesn’t work for me (*Error occurred while saving your data.”), and when I report that the comment system doesn’t work to MSDN, I get no reply. I’ve been trying to create railroad diagrams for all the important SQL Server SQL statements, as good as you’d find for Oracle, and have so far published the CREATE TABLE and ALTER TABLE railroad diagrams based on the BNF. Although I’ve been aware of them, I’ve never realised until recently how many errors there are. Then, Colin Daley created a translator for the SQL Server dialect of  BNF which outputs standard EBNF notation used by the W3C. The example MSDN BNF for the trigger would be rendered as … /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ create_trigger ::= 'CREATE TRIGGER' ( schema_name '.' ) ? trigger_name 'ON' ( table | view ) ( 'WITH' dml_trigger_option ( ',' dml_trigger_option ) * ) ? ( 'FOR' | 'AFTER' | 'INSTEAD OF' ) ( ( 'INSERT' ) ? ( ',' ) ? ( 'UPDATE' ) ? ( ',' ) ? ( 'DELETE' ) ? ) ( 'NOT FOR REPLICATION' ) ? 'AS' ( ( sql_statement ( ';' ) ? ) + | 'EXTERNAL NAME' method_specifier ( ';' ) ? )   dml_trigger_option ::= ( 'ENCRYPTION' ) ? ( 'EXECUTE AS CLAUSE' ) ?   method_specifier ::= assembly_name '.' class_name '.' method_name Colin’s intention was to allow anyone to paste SQL Server’s BNF notation into his website-based parser, and from this generate classic railroad diagrams via Gunther Rademacher's Railroad Diagram Generator.  Colin's application does this for you: you're not aware that you are moving to a different site.  Because Colin's 'translator' it is a parser, it will pick up syntax errors. Once you’ve fixed the syntax errors, you will get the syntax in the form of a human-readable railroad diagram and, in this form, the semantic mistakes become flamingly obvious. Gunter’s Railroad Diagram Generator is brilliant. To be able, after correcting the MSDN dialect of BNF, to generate a standard EBNF, and from thence to create railroad diagrams for SQL Server’s syntax that are as good as Oracle’s, is a great boon, and many thanks to Colin for the idea. Here is the result of the W3C EBNF from Colin’s application then being run through the Railroad diagram generator. create_trigger: dml_trigger_option: method_specifier:   Now that’s much better, you’ll agree. This is pretty easy to understand, and at this point any error is immediately obvious. This should be seriously useful, and it is to me. However  there is that snag. The BNF is generally incorrect, and you can’t expect the average visitor to mess about with it. The answer is, of course, to correct the BNF on MSDN and maybe even add railroad diagrams for the syntax. Stop giggling! I agree it won’t happen. In the meantime, we need to collaboratively store and publish these corrected syntaxes ourselves as we do them. How? GitHub?  SQL Server Central?  Simple-Talk? What should those of us who use the system  do with our corrected EBNF so that anyone can use them without hassle?

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• Use Autoruns to Manually Clean an Infected PC

  - by Mark Virtue

  There are many anti-malware programs out there that will clean your system of nasties, but what happens if you’re not able to use such a program?  Autoruns, from SysInternals (recently acquired by Microsoft), is indispensable when removing malware manually. There are a few reasons why you may need to remove viruses and spyware manually: Perhaps you can’t abide running resource-hungry and invasive anti-malware programs on your PC You might need to clean your mom’s computer (or someone else who doesn’t understand that a big flashing sign on a website that says “Your computer is infected with a virus – click HERE to remove it” is not a message that can necessarily be trusted) The malware is so aggressive that it resists all attempts to automatically remove it, or won’t even allow you to install anti-malware software Part of your geek credo is the belief that anti-spyware utilities are for wimps Autoruns is an invaluable addition to any geek’s software toolkit.  It allows you to track and control all programs (and program components) that start automatically with Windows (or with Internet Explorer).  Virtually all malware is designed to start automatically, so there’s a very strong chance that it can be detected and removed with the help of Autoruns. We have covered how to use Autoruns in an earlier article, which you should read if you need to first familiarize yourself with the program. Autoruns is a standalone utility that does not need to be installed on your computer.  It can be simply downloaded, unzipped and run (link below).  This makes is ideally suited for adding to your portable utility collection on your flash drive. When you start Autoruns for the first time on a computer, you are presented with the license agreement: After agreeing to the terms, the main Autoruns window opens, showing you the complete list of all software that will run when your computer starts, when you log in, or when you open Internet Explorer: To temporarily disable a program from launching, uncheck the box next to it’s entry.  Note:  This does not terminate the program if it is running at the time – it merely prevents it from starting next time.  To permanently prevent a program from launching, delete the entry altogether (use the Delete key, or right-click and choose Delete from the context-menu)).  Note:  This does not remove the program from your computer – to remove it completely you need to uninstall the program (or otherwise delete it from your hard disk). Suspicious Software It can take a fair bit of experience (read “trial and error”) to become adept at identifying what is malware and what is not.  Most of the entries presented in Autoruns are legitimate programs, even if their names are unfamiliar to you.  Here are some tips to help you differentiate the malware from the legitimate software: If an entry is digitally signed by a software publisher (i.e. there’s an entry in the Publisher column) or has a “Description”, then there’s a good chance that it’s legitimate If you recognize the software’s name, then it’s usually okay.  Note that occasionally malware will “impersonate” legitimate software, but adopting a name that’s identical or similar to software you’re familiar with (e.g. “AcrobatLauncher” or “PhotoshopBrowser”).  Also, be aware that many malware programs adopt generic or innocuous-sounding names, such as “Diskfix” or “SearchHelper” (both mentioned below). Malware entries usually appear on the Logon tab of Autoruns (but not always!) If you open up the folder that contains the EXE or DLL file (more on this below), an examine the “last modified” date, the dates are often from the last few days (assuming that your infection is fairly recent) Malware is often located in the C:\Windows folder or the C:\Windows\System32 folder Malware often only has a generic icon (to the left of the name of the entry) If in doubt, right-click the entry and select Search Online… The list below shows two suspicious looking entries:  Diskfix and SearchHelper These entries, highlighted above, are fairly typical of malware infections: They have neither descriptions nor publishers They have generic names The files are located in C:\Windows\System32 They have generic icons The filenames are random strings of characters If you look in the C:\Windows\System32 folder and locate the files, you’ll see that they are some of the most recently modified files in the folder (see below) Double-clicking on the items will take you to their corresponding registry keys: Removing the Malware Once you’ve identified the entries you believe to be suspicious, you now need to decide what you want to do with them.  Your choices include: Temporarily disable the Autorun entry Permanently delete the Autorun entry Locate the running process (using Task Manager or similar) and terminating it Delete the EXE or DLL file from your disk (or at least move it to a folder where it won’t be automatically started) or all of the above, depending upon how certain you are that the program is malware. To see if your changes succeeded, you will need to reboot your machine, and check any or all of the following: Autoruns – to see if the entry has returned Task Manager (or similar) – to see if the program was started again after the reboot Check the behavior that led you to believe that your PC was infected in the first place.  If it’s no longer happening, chances are that your PC is now clean Conclusion This solution isn’t for everyone and is most likely geared to advanced users. Usually using a quality Antivirus application does the trick, but if not Autoruns is a valuable tool in your Anti-Malware kit. Keep in mind that some malware is harder to remove than others.  Sometimes you need several iterations of the steps above, with each iteration requiring you to look more carefully at each Autorun entry.  Sometimes the instant that you remove the Autorun entry, the malware that is running replaces the entry.  When this happens, we need to become more aggressive in our assassination of the malware, including terminating programs (even legitimate programs like Explorer.exe) that are infected with malware DLLs. Shortly we will be publishing an article on how to identify, locate and terminate processes that represent legitimate programs but are running infected DLLs, in order that those DLLs can be deleted from the system. Download Autoruns from SysInternals Similar Articles Productive Geek Tips Using Autoruns Tool to Track Startup Applications and Add-onsHow To Get Detailed Information About Your PCSUPERAntiSpyware Portable is the Must-Have Spyware Removal Tool You NeedQuick Tip: Windows Vista Temp Files DirectoryClear Recent Commands From the Run Dialog in Windows XP TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional 15 Great Illustrations by Chow Hon Lam Easily Sync Files & Folders with Friends & Family Amazon Free Kindle for PC Download Stretch popurls.com with a Stylish Script (Firefox) OldTvShows.org – Find episodes of Hitchcock, Soaps, Game Shows and more Download Microsoft Office Help tab

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• Ghost team foundation build controllers

  - by Martin Hinshelwood

  Quite often after an upgrade there are things left over. Most of the time they are easy to delete, but sometimes it takes a little effort. Even rarer are those times when something just will not go away no matter how much you try. We have had a ghost team build controller hanging around for a while now, and it had defeated my best efforts to get rid of it. The build controller was from our old TFS server from before our TFS 2010 beta 2 upgrade and was really starting to annoy me. Every time I try to delete it I get the message: Controller cannot be deleted because there are build in progress -Manage Build Controller dialog   Figure: Deleting a ghost controller does not always work. I ended up checking all of our 172 Team Projects for the build that was queued, but did not find anything. Jim Lamb pointed me to the “tbl_BuildQueue” table in the team Project Collection database and sure enough there was the nasty little beggar. Figure: The ghost build was easily spotted Adam Cogan asked me: “Why did you suspect this one?” Well, there are a number of things that led me to suspect it: QueueId is very low: Look at the other items, they are in the thousands not single digits ControllerId: I know there is only one legitimate controller, and I am assuming that 6 relates to “zzUnicorn” DefinitionId: This is a very low number and I looked it up in “tbl_BuildDefinition” and it did not exist QueueTime: As we did not upgrade to TFS 2010 until late 2009 a date of 2008 for a queued build is very suspect Status: A status of 2 means that it is still queued This build must have been queued long ago when we were using TFS 2008, probably a beta, and it never got cleaned up. As controllers are new in TFS 2010 it would have created the “zzUnicorn” controller to handle any build servers that already exist. I had previously deleted the Agent, but leaving the controller just looks untidy. Now that the ghost build has been identified there are two options: Delete the row I would not recommend ever deleting anything from the database to achieve something in TFS. It is really not supported. Set the Status to cancelled (Recommended) This is the best option as TFS will then clean it up itself So I set the Status of this build to 2 (cancelled) and sure enough it disappeared after a couple of minutes and I was then able to then delete the “zzUnicorn” controller. Figure: Almost completely clean Now all I have to do is get rid of that untidy “zzBunyip” agent, but that will require rewriting one of our build scripts which will have to wait for now.   Technorati Tags: ALM,TFBS,TFS 2010

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• Deprecate UPDATE FROM? Not if I can help it!

  - by AaronBertrand

  Fellow MVP Hugo Kornelis ( blog ) has suggested that the proprietary UPDATE FROM and DELETE FROM syntax, which has worked for several SQL Server versions, should be deprecated in favor of MERGE. Here is the Connect item he raised: #332437 : Deprecate UPDATE FROM and DELETE FROM As you can see, the response is quite divided (more so than any other item that I can recall) - at the time of writing, it was 11 up-votes and 12 down-votes. I have no shame in admitting that I am one of the people who down-voted...(read more)

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• Stairway to XML: Level 8 - Deleting Data from an XML Instance

  in order to use the modify() method to delete data from typed and untyped XML instances, you must pass an XML DML expression as an argument to the method. That expression must include the delete keyword, along with an XQuery expression that defines the XML component to be deleted. Robert makes it seem simple, as usual. The best way to version control T-SQLSSMS plug-in SQL Source Control connects SVN, TFS, Git, Hg and all others to SQL Server. Learn more.

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• Use a partial in a partial?

  - by Greg Wallace

  I'm a Rails newbie, so bear with me. I have a few places, some pages, some partials that use: <%= link_to "delete", post, method: :delete, data: { confirm: "You sure?" }, title: post.content %> Would it make sense to make this a partial since it is used repeatedly, sometimes in other partials too? Is it o.k. to put partials in partials?

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• Unable to add users to Microsoft Dynamics CRM 4.0 after database restore

  - by Wes Weeks

  Working with a client in our Multi-tenant CRM environment who was doing a database migration into CRM and as part of the process, a backup of their Organization_MSCRM database was taken just prior to starting the migration in case it needed to be restored and run a second time. In this case it did, so I restored the database and let the client know he should be good to go.  A few hours later I received a call that they were unable to add some new users, they would appear as available when using the add multiple user wizard, but anyone added would not be added to CRM.  It was also disucussed that these users had been added to CRM initally AFTER the database backup had been taken. I turned on tracing and tried to add the users through both the single user form and multiple user interface and was unable to do so.  The error message in the logs wasn't much help: Unexpected error adding user [email protected]: Microsoft.Crm.CrmException: INVALID_WRPC_TOKEN: Validate WRPC Token: WRPCTokenState=Invalid, TOKEN_EXPIRY=4320, IGNORE_TOKEN=False Searching on Google or bing didn't offer any assitance.  Apparently not a very common problem, or no one has been able to resolve. I did some searching in the MSCRM_CONFIG database and found that their are several user tables there and after getting my head around the structure found that there were enties here for users that were not part of the restored DB.  It seems that new users are added to both the Orgnaization_MSCRM and MSCRM_CONFIG and after the restore these were out of sync. I needed to remove the extra entries in order to address.  Restoring the MSCRM_CONFIG database was not an option as other clients could have been adding users at this point and to restore would risk breaking their instances of CRM.  Long story short, I was finally able to generate a script to remove the bad entries and when I tried to add users again, I was succesful.  In case someone else out there finds themselves in a similar situation, here is the script I used to delete the bad entries. DECLARE @UsersToDelete TABLE (   UserId uniqueidentifier )   Insert Into @UsersToDelete(UserId) Select UserId from [MSCRM_CONFIG].[dbo].[SystemUserOrganizations] Where CrmuserId Not in (select systemuserid from Organization_MSCRM.dbo.SystemUserBase) And OrganizationId = '00000000-643F-E011-0000-0050568572A1' --Id From the Organization table for this instance   Delete From [MSCRM_CONFIG].[dbo].[SystemUserAuthentication]   Where UserId in (Select UserId From @UsersToDelete)   Delete From [MSCRM_CONFIG].[dbo].[SystemUserOrganizations] Where UserId in (Select UserId From @UsersToDelete)   Delete From [MSCRM_CONFIG].[dbo].[SystemUser] Where Id in (Select UserId From @UsersToDelete)

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• Announcing: Improvements to the Windows Azure Portal

  - by ScottGu

  Earlier today we released a number of enhancements to the new Windows Azure Management Portal.  These new capabilities include: Service Bus Management and Monitoring Support for Managing Co-administrators Import/Export support for SQL Databases Virtual Machine Experience Enhancements Improved Cloud Service Status Notifications Media Services Monitoring Support Storage Container Creation and Access Control Support All of these improvements are now live in production and available to start using immediately.  Below are more details on them: Service Bus Management and Monitoring The new Windows Azure Management Portal now supports Service Bus management and monitoring. Service Bus provides rich messaging infrastructure that can sit between applications (or between cloud and on-premise environments) and allow them to communicate in a loosely coupled way for improved scale and resiliency. With the new Service Bus experience, you can now create and manage Service Bus Namespaces, Queues, Topics, Relays and Subscriptions. You can also get rich monitoring for Service Bus Queues, Topics and Subscriptions. To create a Service Bus namespace, you can now select the “Service Bus” tab in the Windows Azure portal and then simply select the CREATE command: Doing so will bring up a new “Create a Namespace” dialog that allows you to name and create a new Service Bus Namespace: Once created, you can obtain security credentials associated with the Namespace via the ACCESS KEY command. This gives you the ability to obtain the connection string associated with the service namespace. You can copy and paste these values into any application that requires these credentials: It is also now easy to create Service Bus Queues and Topics via the NEW experience in the portal drawer.  Simply click the NEW command and navigate to the “App Services” category to create a new Service Bus entity: Once you provision a new Queue or Topic it can be managed in the portal.  Clicking on a namespace will display all queues and topics within it: Clicking on an item in the list will allow you to drill down into a dashboard view that allows you to monitor the activity and traffic within it, as well as perform operations on it. For example, below is a view of an “orders” queue – note how we now surface both the incoming and outgoing message flow rate, as well as the total queue length and queue size: To monitor pub/sub subscriptions you can use the ADD METRICS command within a topic and select a specific subscription to monitor. Support for Managing Co-Administrators You can now add co-administrators for your Windows Azure subscription using the new Windows Azure Portal. This allows you to share management of your Windows Azure services with other users. Subscription co-administrators share the same administrative rights and permissions that service administrator have - except a co-administrator cannot change or view billing details about the account, nor remove the service administrator from a subscription. In the SETTINGS section, click on the ADMINISTRATORS tab, and select the ADD button to add a co-administrator to your subscription: To add a co-administrator, you specify the email address for a Microsoft account (formerly Windows Live ID) or an organizational account, and choose the subscription you want to add them to: You can later update the subscriptions that the co-administrator has access to by clicking on the EDIT button, and then select or deselect the subscriptions to which they belong. Import/Export Support for SQL Databases The Windows Azure administration portal now supports importing and exporting SQL Databases to/from Blob Storage.  Databases can be imported/exported to blob storage using the same BACPAC file format that is supported with SQL Server 2012.  Among other benefits, this makes it easy to copy and migrate databases between on-premise and cloud environments. SQL Databases now have an EXPORT command in the bottom drawer that when pressed will prompt you to save your database to a Windows Azure storage container: The UI allows you to choose an existing storage account or create a new one, as well as the name of the BACPAC file to persist in blob storage: You can also now import and create a new SQL Database by using the NEW command.  This will prompt you to select the storage container and file to import the database from: The Windows Azure Portal enables you to monitor the progress of import and export operations. If you choose to log out of the portal, you can come back later and check on the status of all of the operations in the new history tab of the SQL Database server – this shows your entire import and export history and the status (success/fail) of each: Enhancements to the Virtual Machine Experience One of the common pain-points we have heard from customers using the preview of our new Virtual Machine support has been the inability to delete the associated VHDs when a VM instance (or VM drive) gets deleted. Prior to today’s release the VHDs would continue to be in your storage account and accumulate storage charges. You can now navigate to the Disks tab within the Virtual Machine extension, select a VM disk to delete, and click the DELETE DISK command: When you click the DELETE DISK button you have the option to delete the disk + associated .VHD file (completely clearing it from storage).  Alternatively you can delete the disk but still retain a .VHD copy of it in storage. Improved Cloud Service Status Notifications The Windows Azure portal now exposes more information of the health status of role instances.  If any of the instances are in a non-running state, the status at the top of the dashboard will summarize the status (and update automatically as the role health changes): Clicking the instance hyperlink within this status summary view will navigate you to a detailed role instance view, and allow you to get more detailed health status of each of the instances.  The portal has been updated to provide more specific status information within this detailed view – giving you better visibility into the health of your app: Monitoring Support for Media Services Windows Azure Media Services allows you to create media processing jobs (for example: encoding media files) in your Windows Azure Media Services account. In the Windows Azure Portal, you can now monitor the number of encoding jobs that are queued up for processing as well as active, failed and queued tasks for encoding jobs. On your media services account dashboard, you can visualize the monitoring data for last 6 hours, 24 hours or 7 days. Storage Container Creation and Access Control Support You can now create Windows Azure Storage storage containers from within the Windows Azure Portal.  After selecting a storage account, you can navigate to the CONTAINERS tab and click the ADD CONTAINER command: This will display a dialog that lets you name the new container and control access to it: You can also update the access setting as well as container metadata of existing containers by selecting one and then using the new EDIT CONTAINER command: This will then bring up the edit container dialog that allows you to change and save its settings: In addition to creating and editing containers, you can click on them within the portal to drill-in and view blobs within them.  Summary The above features are all now live in production and available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using them today.  Visit the Windows Azure Developer Center to learn more about how to build apps with it. We’ll have even more new features and enhancements coming later this month – including support for the recent Windows Server 2012 and .NET 4.5 releases (we will enable new web and worker role images with Windows Server 2012 and .NET 4.5, and support .NET 4.5 with Websites).  Keep an eye out on my blog for details as these new features become available. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• How to store Role Based Access rights in web application?

  - by JonH

  Currently working on a web based CRM type system that deals with various Modules such as Companies, Contacts, Projects, Sub Projects, etc. A typical CRM type system (asp.net web form, C#, SQL Server backend). We plan to implement role based security so that basically a user can have one or more roles. Roles would be broken down by first the module type such as: -Company -Contact And then by the actions for that module for instance each module would end up with a table such as this: Role1 Example: Module Create Edit Delete View Company Yes Owner Only No Yes Contact Yes Yes Yes Yes In the above case Role1 has two module types (Company, and Contact). For company, the person assigned to this role can create companies, can view companies, can only edit records he/she created and cannot delete. For this same role for the module contact this user can create contacts, edit contacts, delete contacts, and view contacts (full rights basically). I am wondering is it best upon coming into the system to session the user's role with something like a: List<Role> roles; Where the Role class would have some sort of List<Module> modules; (can contain Company, Contact, etc.).? Something to the effect of: class Role{ string name; string desc; List<Module> modules; } And the module action class would have a set of actions (Create, Edit, Delete, etc.) for each module: class ModuleActions{ List<Action> actions; } And the action has a value of whether the user can perform the right: class Action{ string right; } Just a rough idea, I know the action could be an enum and the ModuleAction can probably be eliminated with a List<x, y>. My main question is what would be the best way to store this information in this type of application: Should I store it in the User Session state (I have a session class where I manage things related to the user). I generally load this during the initial loading of the application (global.asax). I can simply tack onto this session. Or should this be loaded at the page load event of each module (page load of company etc..). I eventually need to be able to hide / unhide various buttons / divs based on the user's role and that is what got me thinking to load this via session. Any examples or points would be great.

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• keyboard is not working properly

  - by kumar shivam

  i installed ubuntu 12.04 and it was working perfectly, but from yesterday i have a problem, when i am pressing left ctrl key it doesn't responding but when i pressed Fn key it works as a ctrl key and loses its own functioning,same with the delete(del) key it works as a pause/break key and pause/break key is working as a delete key.numlock key is working as a print screen key, after that i updated my os but the problem is still happening. pls tell me what to do.

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• Sorting a Linked List [closed]

  - by Mohit Sehgal

  I want to sort a linked list. Here Node is class representing a node in a Linked List I have written a code to bubble sort a linked list. Program does not finishes execution. Kindly point out the mistakes. class Node { public: int data; public: Node *next; Node() { data=0;next=0; } Node(int d) { data=d; } void setData(int d) { data=d; } void print() { cout<<data<<endl; } bool operator==(Node n) { return this->data==n.data; } bool operator >(Node d) { if((this->data) > (d.data)) return true; return false; } }; class LList { public: int noOfNodes; Node *start;/*Header Node*/ LList() { start=new Node; noOfNodes=0;start=0; } void addAtFront(Node* n) { n->next=(start); start=n; noOfNodes++; } void addAtLast(Node* n) { Node *cur=(start); n->next=NULL; if(start==NULL) { start=n; noOfNodes++; return; } while(cur->next!=NULL) { cur=cur->next; } cur->next=n; noOfNodes++; } void addAtPos(Node *n,int pos) { if(pos==1) { addAtFront(n);return; } Node *cur=(start); Node *prev=NULL; int curPos=0; n->next=NULL; while(cur!=NULL) { curPos++; if(pos==curPos+1) { prev=cur; } if(pos==curPos) { n->next=cur; prev->next=n; break; } cur=cur->next; } noOfNodes++; } void removeFirst() { Node *del=start; start=start->next; delete del; noOfNodes--; return; } void removeLast() { Node *cur=start,*prev=NULL; while(cur->next!=NULL) { prev=cur; cur=cur->next; } prev->next=NULL; Node *del=cur->next; delete del; noOfNodes--; return; } void removeNodeAt(int pos) { if(pos<1) return; if(pos==1) { removeFirst();return;} int curPos=1; Node* cur=start->next; Node* prev=start; Node* del=NULL; while(curPos<pos&&cur!=NULL) { curPos++; if(curPos==pos) { del=cur; prev->next=cur->next; cur->next=NULL; delete del; noOfNodes--; break; } prev=prev->next; cur=cur->next; } } void removeNode(Node *d) { Node *cur=start; if(*d==*cur) { removeFirst();return; } cur=start->next; Node *prev=start,*del=NULL; while(cur!=NULL) { if(*cur==*d) { del=cur; prev->next=cur->next; delete del; noOfNodes--; break; } prev=prev->next; cur=cur->next; } } int getPosition(Node data) { int pos=0; Node *cur=(start); while(cur!=NULL) { pos++; if(*cur==data) { return pos; } cur=cur->next; } return -1;//not found } Node getNode(int pos) { if(pos<1) return -1;// not a valid position else if(pos>noOfNodes) return -1; // not a valid position Node *cur=(start); int curPos=0; while(cur!=NULL) { if(++curPos==pos) return *cur; cur=cur->next; } } void reverseList()//reverse the list { Node* cur=start->next; Node* d=NULL; Node* prev=start; while(cur!=NULL) { d=cur->next; cur->next=start; start=cur; prev->next=d; cur=d; } } void sortBubble() { Node *i=start,*j=start,*prev=NULL,*temp=NULL,*after=NULL; int count=noOfNodes-1;int icount=0; while(i->next!=NULL) { j=start; after=j->next; icount=0; while(++icount!=count) { if((*j)>(*after)) { temp=after->next; after->next=j; prev->next=j->next; j->next=temp; prev=after; after=j->next; } else{ prev=j; j=after; after=after->next; } } i=i->next; count--; } } void traverse() { Node *cur=(start); int c=0; while(cur!=NULL) { // cout<<"start"<<start; c++; cur->print(); cur=cur->next; } noOfNodes=c; } ~LList() { delete start; } }; int main() { int n; cin>>n; int d; LList list; Node *node; Node *temp=new Node(2123); for(int i=0;i<n;i++) { cin>>d; node=new Node(d); list.addAtLast(node); } list.addAtPos(temp,1); cout<<"traverse\n"; list.traverse(); temp=new Node(12); list.removeNode(temp); cout<<"12 removed"; list.traverse(); list.reverseList(); cout<<"\nreversed\n"; list.traverse(); cout<<"bubble sort\n"; list.sortBubble(); list.traverse(); getch(); delete node; return 0; }

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• C++11 Tidbits: access control under SFINAE conditions

  - by Paolo Carlini

  Lately I have been spending quite a bit of time on the SFINAE ("Substitution failure is not an error") features of C++, fixing and tweaking various bits of the GCC implementation. An important missing piece was the implementation of the resolution of DR 1170 which, in a nutshell, mandates that access checking is done as part of the substitution process. Consider: class C { typedef int type; }; template <class T, class = typename T::type> auto f(int) - char; template <class> auto f(...) -> char (&)[2]; static_assert (sizeof(f<C>(0)) == 2, "Ouch"); According to the resolution, the static_assert should not fire, and the snippet should compile successfully. The reason being that the first f overload must be removed from the candidate set because C::type is private to C. On the other hand, before the resolution of DR 1170, the expected behavior was for the first overload to remain in the candidate set, win over the second one, to eventually lead to an access control error (*). GCC mainline (would be 4.8) finally implements the DR, thus benefiting the many modern programming techniques heavily exploiting SFINAE, among which certainly the GNU C++ runtime library itself, which relies on it for the internals of <type_traits> and in several other places. Note that the resolution of the DR is active even in C++98 mode, not just in C++11 mode, because it turned out that the traditional behavior, as implemented in GCC, wasn't fully consistent in all the possible circumstances. (*) In practice, GCC didn't really implement this, the static_assert triggered instead.

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• mongoDB Management Studio

  - by Liam McLennan

  This weekend I have been in Sydney at the MS Web Camp, learning about web application development. At the end of the first day we came up with application ideas and pitched them. My idea was to build a web management application for mongoDB. mongoDB I pitched my idea, put down the microphone, and then someone asked, “what’s mongo?”. Good question. MongoDB is a document database that stores JSON style documents. This is a JSON document for a tweet from twitter: db.tweets.find()[0] { "_id" : ObjectId("4bfe4946cfbfb01420000001"), "created_at" : "Thu, 27 May 2010 10:25:46 +0000", "profile_image_url" : "http://a3.twimg.com/profile_images/600304197/Snapshot_2009-07-26_13-12-43_normal.jpg", "from_user" : "drearyclocks", "text" : "Does anyone know who has better coverage, Optus or Vodafone? Telstra is still too expensive.", "to_user_id" : null, "metadata" : { "result_type" : "recent" }, "id" : { "floatApprox" : 14825648892 }, "geo" : null, "from_user_id" : 6825770, "search_term" : "telstra", "iso_language_code" : "en", "source" : "&lt;a href=&quot;http://www.tweetdeck.com&quot; rel=&quot;nofollow&quot;&gt;TweetDeck&lt;/a&gt;" } A mongodb server can have many databases, each database has many collections (instead of tables) and a collection has many documents (instead of rows). Development Day 2 of the Sydney MS Web Camp was allocated to building our applications. First thing in the morning I identified the stories that I wanted to implement: Scenario: View databases Scenario: View Collections in a database Scenario: View Documents in a Collection Scenario: Delete a Collection Scenario: Delete a Database Scenario: Delete Documents Over the course of the day the team (3.5 developers) implemented all of the planned stories (except ‘delete a database’) and also implemented the following: Scenario: Create Database Scenario: Create Collection Lessons Learned I’m new to MongoDB and in the past I have only accessed it from Ruby (for my hare-brained scheme). When it came to implementing our MongoDB management studio we discovered that their is no official MongoDB driver for .NET. We chose to use NoRM, honestly just because it was the only one I had heard of. NoRM was a challenge. I think it is a fine library but it is focused on mapping strongly typed objects to MongoDB. For our application we had no prior knowledge of the types that would be in the MongoDB database so NoRM was probably a poor choice. Here are some screens (click to enlarge):

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• Should UTF-16 be considered harmful?

  - by Artyom

  I'm going to ask what is probably quite a controversial question: "Should one of the most popular encodings, UTF-16, be considered harmful?" Why do I ask this question? How many programmers are aware of the fact that UTF-16 is actually a variable length encoding? By this I mean that there are code points that, represented as surrogate pairs, take more than one element. I know; lots of applications, frameworks and APIs use UTF-16, such as Java's String, C#'s String, Win32 APIs, Qt GUI libraries, the ICU Unicode library, etc. However, with all of that, there are lots of basic bugs in the processing of characters out of BMP (characters that should be encoded using two UTF-16 elements). For example, try to edit one of these characters: 𝄞 (U+1D11E) MUSICAL SYMBOL G CLEF 𝕥 (U+1D565) MATHEMATICAL DOUBLE-STRUCK SMALL T 𝟶 (U+1D7F6) MATHEMATICAL MONOSPACE DIGIT ZERO 𠂊 (U+2008A) Han Character You may miss some, depending on what fonts you have installed. These characters are all outside of the BMP (Basic Multilingual Plane). If you cannot see these characters, you can also try looking at them in the Unicode Character reference. For example, try to create file names in Windows that include these characters; try to delete these characters with a "backspace" to see how they behave in different applications that use UTF-16. I did some tests and the results are quite bad: Opera has problem with editing them (delete required 2 presses on backspace) Notepad can't deal with them correctly (delete required 2 presses on backspace) File names editing in Window dialogs in broken (delete required 2 presses on backspace) All QT3 applications can't deal with them - show two empty squares instead of one symbol. Python encodes such characters incorrectly when used directly u'X'!=unicode('X','utf-16') on some platforms when X in character outside of BMP. Python 2.5 unicodedata fails to get properties on such characters when python compiled with UTF-16 Unicode strings. StackOverflow seems to remove these characters from the text if edited directly in as Unicode characters (these characters are shown using HTML Unicode escapes). WinForms TextBox may generate invalid string when limited with MaxLength. It seems that such bugs are extremely easy to find in many applications that use UTF-16. So... Do you think that UTF-16 should be considered harmful?

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• I installed the Nautilus Actions Configuration utility but I don't have the action configuration menu option

  - by userman

  I am tyring to set up my trash to securely delete items and I am following the instructions on this page. http://techthrob.com/2010/07/07/adding-a-secure-delete-option-to-nautilus-file-manager-in-linux/ I installed the Nautilus Actions Configuration utility and according to the previously listed page a new action configuration menu option should have shown up in the Nautilus preferences menu. It didn't. Any help would be appreciated. Thanks!

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• How to record streaming camera video and auto-erase old data before drive fills up?

  - by nLinked

  I'm interested in making my own home CCTV system using Ubuntu. I want to get network cameras similar to this: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260745150596 I want a way to dump or record the live stream to a large hard drive, but have Ubuntu automatically delete the oldest parts of the video while the drive fills, so it can continue recording new data continuously. How can this auto-delete while recording be accomplished? I've searched and searched.

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