altering tables - Page 303

How do I make software that preserves database integrity and correctness? Please help, confused.

- by user287745

i have made an application project in vs 08 c#, sql server from vs 08. the database has like 20 tables and many fields in each have made an interface for adding deleting editting and retrieving data according to predefined needs of the users. now i have to 1) make to project in to a software which i can deliver to professor. that is he can just double click the icon and the software simply starts. no vs 08 needed to start the debugging 2) the database will be on one powerful computer (dual core latest everything win xp) and the user will access it from another computer connected using LAN i am able to change the connection string to the shared database using vs 08/ debugger whenever the server changes but how am i supposed to do that when its a software? 3)there will by many clients am i supposed to give the same software to every one, so they all can connect to the database, how will the integrity and correctness of the database be maintained? i mean the db.mdf file will be in a folder which will be shared with read and write access. so its not necessary that only one user will write at a time. so is there any coding for this or? please help me out here i am stuck do not know what to do i have no practical experience, would appreciate all the help thank you

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How do I Order on common attribute of two models in the DB?

- by Will

If i have two tables Books, CDs with corresponding models. I want to display to the user a list of books and CDs. I also want to be able to sort this list on common attributes (release date, genre, price, etc.). I also have basic filtering on the common attributes. The list will be large so I will be using pagination in manage the load. items = [] items << CD.all(:limit => 20, :page => params[:page], :order => "genre ASC") items << Book.all(:limit => 20, :page => params[:page], :order => "genre ASC") re_sort(items,"genre ASC") Right now I am doing two queries concatenating them and then sorting them. This is very inefficient. Also this breaks down when I use paging and filtering. If I am on page 2 of how do I know what page of each table individual table I am really on? There is no way to determine this information without getting all items from each table. I have though that if I create a new Class called items that has a one to one relationship with either a Book or CD and do something like Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "genre ASC") However this gives back an ambiguous error. So can only be refined as Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "books.genre ASC") And does not interleave the books and CDs in a way that I want. Any suggestions.

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Help with create action in a different show page

- by Andrew

Hi, I'm a Rails newbie and want to do something but keep messing something up. I'd love some help. I have a simple app that has three tables. Users, Robots, and Recipients. Robots belong_to users and Recipients belong_to robots. On the robot show page, I want to be able to create recipients for that robot right within the robot show page. I have the following code in the robot show page which lists current recipients: <table> <% @robot.recipients.each do |recipient| %> <tr> <td><b><%=h recipient.chat_screen_name %></b> via <%=h recipient.protocol_name</td> <td><%= link_to 'Edit', edit_recipient_path(recipient) %> </td> <td><%= link_to 'Delete', recipient, :confirm => 'Are you sure?', :method => :delete %></td> </tr> <% end %> </table> What I'd like to do is have an empty field in which the user can add a new recipient, and have tried the following: I added this to the Robots Show view: <% form_for(@robot.recipient) do |f| %> Enter the screen name<br> <%= f.text_field :chat_screen_name %> <p> <%= f.submit 'Update' %> </p> <% end %> and then this to the Robot controller in the show action: @recipient = Recipient.new @recipients = Recipient.all Alas, I'm still getting a NoMethod error that says: "undefined method `recipient' for #" I'm not sure what I'm missing. Any help would be greatly appreciated. Thank you.

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NHibernate will not insert a record

- by Brian Beckham

I have an application that is now 4+ years old that is exhibiting some odd behavior on our latest deployment. The application uses nHibernate for all inserts / updates / selects, etc. We are currently using .NET 2.0, and nHibernate 1.2 (I know, we need to upgrade) This deployment is on Windows 2008 Server x64, IIS 7.5 - what I have seen so far is that the application runs, but is unable to insert or update records in the DB - reads seem fine so far, but writes are a problem. SOME writes actually work, inserts into some small tables, but most never even make it to the DB. Using SQL Profiler, the insert / updates never make it to the server, and turning log4net up to DEBUG, and show_sql true - the select statements appear, but the insert / update statements never make it into the log at all, and never show up at the server. What's even more odd is that the application seems to be oblivious to this - the commandandclose runs without exception (open session in view with an httpmodule), the domain objects come back with uuid's generated, etc. but never get persisted. Certainly an upgrade is due, but I would hate to try it during a deployment, and without time to accurately test the app. Any ideas?

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Why does the WCF 3.5 REST Starter Kit do this?

- by Brandon

I am setting up a REST endpoint that looks like the following: [WebInvoke(Method = "POST", UriTemplate = "?format=json", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json)] and [WebInvoke(Method = "DELETE", UriTemplate = "?token={token}&format=json", ResponseFormat = WebMessageFormat.Json)] The above throws the following error: UriTemplateTable does not support '?format=json' and '?token={token}&format=json' since they are not equivalent, but cannot be disambiguated because they have equivalent paths and the same common literal values for the query string. See the documentation for UriTemplateTable for more detail. I am not an expert at WCF, but I would imagine that it should map first by the HTTP Method and then by the URI Template. It appears to be backwards. If both of my URI templates are: ?token={token}&format=json This works because they are equivalent and it then appears to look at the HTTP Method where one is POST and the other is DELETE. Is REST supposed to work this way? Why are the URI Template Tables not being sorted first by HTTP Method and then by URI Template? This can cause some serious frustrations when 1 HTTP Method requires a parameter and another does not, or if I want to do optional parameters (e.g. if the 'format' parameter is not passed, default to XML).

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Do I need to write a trigger for such a simple constraint?

- by Paul Hanbury

I really had a hard time knowing what words to put into the title of my question, as I am not especially sure if there is a database pattern related to my problem. I will try to simplify matters as much as possible to get directly to the heart of the issue. Suppose I have some tables. The first one is a list of widget types: create table widget_types ( widget_type_id number(7,0) primary key, description varchar2(50) ); The next one contains icons: create table icons ( icon_id number(7,0) primary key, picture blob ); Even though the users get to select their preferred widget, there is a predefined subset of widgets that they can choose from for each widget type. create table icon_associations ( widget_type_id number(7,0) references widget_types, icon_id number(7,0) references icons, primary key (widget_type_id, icon_id) ); create table icon_prefs ( user_id number(7,0) references users, widget_type_id number(7,0), icon_id number(7,0), primary key (user_id, widget_type_id), foreign key (widget_type_id, icon_id) references icon_associations ); Pretty simple so far. Let us now assume that if we are displaying an icon to a user who has not set up his preferences, we choose one of the appropriate images associated with the current widget. I'd like to specify the preferred icon to display in such a case, and here's where I run into my problem: alter table icon_associations add ( is_preferred char(1) check( is_preferred in ('y','n') ) ) ; I do not see how I can enforce that for each widget_type there is one, and only one, row having is_preferred set to 'y'. I know that in MySQL, I am able to write a subquery in my check constraint to quickly resolve this issue. This is not possible with Oracle. Is my mistake that this column has no business being in the icon_associations table? If not where should it go? Is this a case where, in Oracle, the constraint can only be handled with a trigger? I ask only because I'd like to go the constraint route if at all possible. Thanks so much for your help, Paul

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can this problem be solved with a single SQL query?

- by PierrOz

I have the two following tables (with some sample datas) LOGS: ID | SETID | DATE ======================== 1 | 1 | 2010-02-25 2 | 2 | 2010-02-25 3 | 1 | 2010-02-26 4 | 2 | 2010-02-26 5 | 1 | 2010-02-27 6 | 2 | 2010-02-27 7 | 1 | 2010-02-28 8 | 2 | 2010-02-28 9 | 1 | 2010-03-01 STATS: ID | OBJECTID | FREQUENCY | STARTID | ENDID ============================================= 1 | 1 | 0.5 | 1 | 5 2 | 2 | 0.6 | 1 | 5 3 | 3 | 0.02 | 1 | 5 4 | 4 | 0.6 | 2 | 6 5 | 5 | 0.6 | 2 | 6 6 | 6 | 0.4 | 2 | 6 7 | 1 | 0.35 | 3 | 7 8 | 2 | 0.6 | 3 | 7 9 | 3 | 0.03 | 3 | 7 10 | 4 | 0.6 | 4 | 8 11 | 5 | 0.6 | 4 | 8 7 | 1 | 0.45 | 5 | 9 8 | 2 | 0.6 | 5 | 9 9 | 3 | 0.02 | 5 | 9 Every day new logs are analyzed on different sets of objects and stored in table LOGS. Among other processes, some statistics are computed on the objects contained into these sets and the result are stored in table STATS. These statistic are computed through several logs (identified by the STARTID and ENDID columns). So, what could be the SQL query that would give me the latest computed stats for all the objects with the corresponding log dates. In the given example, the result rows would be: OBJECTID | SETID | FREQUENCY | STARTDATE | ENDDATE ====================================================== 1 | 1 | 0.45 | 2010-02-27 | 2010-03-01 2 | 1 | 0.6 | 2010-02-27 | 2010-03-01 3 | 1 | 0.02 | 2010-02-27 | 2010-03-01 4 | 2 | 0.6 | 2010-02-26 | 2010-02-28 5 | 2 | 0.6 | 2010-02-26 | 2010-02-28 So, the most recent stats for set 1 are computed with logs from feb 27 to march 1 whereas stats for set 2 are computed from feb 26 to feb 28. object 6 is not in the results rows as there is no stat on it within the last period of time. Last thing, I use MySQL. Any Idea ?

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MySQL move data from one table to another, matching ID's

- by Reveller

I have (a.o.) two MySQL tables with (a.o.) the following columns: tweets: ------------------------------------- id text from_user_id from_user ------------------------------------- 1 Cool tweet! 13295354 tradeny 2 Tweeeeeeeet 43232544 bolleke 3 Yet another 13295354 tradeny 4 Something.. 53546443 janusz4 users: ------------------------------------- id from_user num_tweets from_user_id ------------------------------------- 1 tradeny 2235 2 bolleke 432 3 janusz4 5354 I now want to normalize the tweets table, replacing tweets.from_user with an integer that matches users.id. Secondly, I want to fill in the corresponding users.from_user_id, Finally, I want to delete tweets.from_user_id so that the end result would look like: tweets: ------------------------ id text from_user ------------------------ 1 Cool tweet! 1 2 Tweeeeeeeet 2 3 Yet another 1 4 Something.. 3 users: ------------------------------------- id from_user num_tweets from_user_id ------------------------------------- 1 tradeny 2235 13295354 2 bolleke 432 43232544 3 janusz4 5354 53546443 My question is whether one could help me form the proper queries for this. I have only come so far: UPDATE tweets SET from_user = (SELECT id FROM users WHERE from_user = tweets.from_user) WHERE... UPDATE users SET from_user_id = (SELECT from_user_id FROM tweets WHERE from_user = tweets.from_user) WHERE... ALTER TABLE tweets DROP from_user_id Any help would be greatly appreciated :-)

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cakephp hasMany through and multiselect form

- by Zoran Kalinic

I'm using cakephp 2.2.2 and I have a problem with the editing view Models and relationships are: Person hasMany OrganizationPerson Organization hasMany OrganizationPerson OrganizationPerson belongs to Person,Organization A basic hasMany through relationship as found within cake documentation. Tables are: people (id,...) organizations (id,...) organization_people (id, person_id,organization_id,...) In the person add and edit forms there is a select box allowing a user to select multiple organization. The problem I have is, when a user edits an existing person, the associated organizations aren't pre-selected. Here is the code in the PeopleController: $organizations = $this->Person->OrganizationPerson->Organization->find('list'); $this->set(compact('organizations')); Related part of the code in the People/edit code looks like: $this->Form->input('OrganizationPerson.organization_id', array('multiple' => true, 'empty' => false)); This will populate the select field, but it does not pre-select it with the Person's associated organizations. Format and content of the $this-data: Array ( [Person] => Array ( [id] => 1 ... ) [OrganizationPerson] => Array ( [0] => Array ( [id] => 1 [person_id] => 1 [organization_id] => 1 ... ) [1] => Array ( [id] => 2 [person_id] => 1 [organization_id] => 2 ... ) ) ) What I have to add/change in the code to get pre-selected organizations? Thanks in advance!

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Database contents setting themselves to 0

- by Luis Armando

I have a Database that contains 4 tables, however I'm using 1 of them which is separated from the others. In this table I have 4 fields which are varchar and the rest are ints (11 other fields), when the users fill up the DB everything gets saved correctly, however it has happened 3 times so far that the database values for the int's reset to 0 without any apparent reason. At first, I thought, it was because those fields (where the numbers should go) were varchars not ints. However since I changed it, it happened again. I've already double checked my code and I have nothing that even updates or inserts a 0 value. Also I'm using codeigniter and active records which protect against SQL injections AND have XSS filtering enabled, could anyone point out something I might be missing or a reason for this to be happening? Also, I'm pretty sure about the answer of this but, is there ANY way to recover some data?? Other than having to ask everyone to fill in everything again.. =/ ** EDIT ** The Storage Engine is MyISAM and Collation is latin1_swedish_ci, Pack Keys are default, for all intents and purposes it's a normal DB

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trouble connecting to MySql DB (PHP)

- by user332817

Hi I have the following PHP code to connect to my db. <?php ob_start(); $host="localhost"; // Host name $username="root"; // Mysql username $password=""; // Mysql password $db_name="test"; // Database name $tbl_name="members"; // Table name // Connect to server and select databse. mysql_connect("$host", "$username", "$password")or die("cannot connect"); ?> however I get the following error: Warning: mysql_connect() [function.mysql-connect]: [2002] A connection attempt failed because the connected party did not (trying to connect via tcp://localhost:3306) in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 Warning: mysql_connect() [function.mysql-connect]: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 Fatal error: Maximum execution time of 30 seconds exceeded in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 I am able to add a db/tables via phpmyadmin but I cant connect using php. here is a screenshot of my phpmyadmin page: http://img294.imageshack.us/img294/1589/sqls.jpg any help would be appreciated, thanks in advance.

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Linq. Help me tune this!

- by dtrick

I have a linq query that is causing some timeout issues. Basically, I have a query that is returning the top 100 results from a table that has approximately 500,000 records. Here is the query: using (var dc = CreateContext()) { var accounts = string.IsNullOrEmpty(searchText) ? dc.Genealogy_Accounts .Where(a => a.Genealogy_AccountClass.Searchable) .OrderByDescending(a => a.ID) .Take(100) : dc.Genealogy_Accounts .Where(a => (a.Code.StartsWith(searchText) || a.Name.StartsWith(searchText)) && a.Genealogy_AccountClass.Searchable) .OrderBy(a => a.Code) .Take(100); return accounts.Select(a => } } Oddly enough it is the first linq query that is causing the timeout. I thought that by doing a 'Take' we wouldn't need to scan all 500k of records. However, that must be what is happening. I'm guessing that the join to find what is 'searchable' is causing the issue. I'm not able to denormalize the tables... so I'm wondering if there is a way to rewrite the linq query to get it to return quicker... or if I should just write this query as a Stored Procedure (and if so, what might it look like). Thanks.

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Can a Snapshot transaction fail and only partially commit in a TransactionScope?

- by Travis Brooks

Greetings I stumbled onto a problem today that seems sort of impossible to me, but its happening...I'm calling some database code in c# that looks something like this: using(var tran = MyDataLayer.Transaction()) { MyDataLayer.ExecSproc(new SprocTheFirst(arg1, arg2)); MyDataLayer.CallSomethingThatEventuallyDoesLinqToSql(arg1, argEtc); tran.Commit(); } I've simplified this a bit for posting, but whats going on is MyDataLayer.Transaction() makes a TransactionScope with the IsolationLevel set to Snapshot and TransactionScopeOption set to Required. This code gets called hundreds of times a day, and almost always works perfectly. However after reviewing some data I discovered there are a handful of records created by "SprocTheFirst" but no corresponding data from "CallSomethingThatEventuallyDoesLinqToSql". The only way that records should exist in the tables I'm looking at is from SprocTheFirst, and its only ever called in this one function, so if its called and succeeded then I would expect CallSomethingThatEventuallyDoesLinqToSql would get called and succeed because its all in the same TransactionScope. Its theoretically possible that some other dev mucked around in the DB, but I don't think they have. We also log all exceptions, and I can find nothing unusual happening around the time that the records from SprocTheFirst were created. So, is it possible that a transaction, or more properly a declarative TransactionScope, with Snapshot isolation level can fail somehow and only partially commit?

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.net printing multiple reports in one document (architecture question)

- by LawsonM

I understand how to print a single document via the PrintDocument class. However, I want to print multiple reports in one document. Each "report" will consist of charts, tables, etc. I want to have two reports per page. I've studied the few examples I can find on how to combine multiple documents into one; however, they always seem to work by creating a collection of objects (e.g. customer or order) that are then iterated over and drawn in the OnPrintPage method. My problem and hence the "architecture" question is that I don't want to cache the objects required to produce the report since they are very large and memory intensive. I'd simply like the resulting "report". One thought I had was to print the report to a metafile, cache that instead in a "MultiplePrintDocument" class and then position those images appropriately two to a page in the OnPrintPage method. I think this would be a lot more efficient and scalable in my case. But I'm not a professional programmer and can't figure out if I'm barking up the wrong tree here. I think the Graphics.BeginContainer and Graphics.Save methods might be relevant, but can't figure out how to implement or if there is a better way. Any pointers would be greatly appreciated.

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In mysql, is "explain ..." always safe?

- by tye

If I allow a group of users to submit "explain $whatever" to mysql (via Perl's DBI using DBD::mysql), is there anything that a user could put into $whatever that would make any database changes, leak non-trivial information, or even cause significant database load? If so, how? I know that via "explain $whatever" one can figure out what tables / columns exist (you have to guess names, though) and roughly how many records are in a table or how many records have a particular value for an indexed field. I don't expect one to be able to get any information about the contents of unindexed fields. DBD::mysql should not allow multiple statements so I don't expect it to be possible to run any query (just explain one query). Even subqueries should not be executed, just explained. But I'm not a mysql expert and there are surely features of mysql that I'm not even aware of. In trying to come up with a query plan, might the optimizer actual execute an expression in order to come up with the value that an indexed field is going to be compared against? explain select * from atable where class = somefunction(...) where atable.class is indexed and not unique and class='unused' would find no records but class='common' would find a million records. Might 'explain' evaluate somefunction(...)? And then could somefunction(...) be written such that it modifies data?

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Looking for Simplified Overview of EJB3

- by sdoca

Hi I'm looking for a simplified overview of EJB3 components. I seem to understand most of the pieces of the puzzle, but can't quite get them to fit together in my brain as a full picture. I've developed numerous web applications (wars) that have been deployed on Tomcat before, but not a full-fledged EE application (ear). I would like the overview to be as generic as possible. I'm not looking for a tutorial on how to set up EJB3 on Glassfish built in NetBeans or some other vendor specific tutorial that's more about the IDE than the technology. I keep reading about Java, ejb-jar, web and ear modules but am not clear on what these different modules contain and how to use them to put together my app. In my case, I want to write a simple database CRUD web application. The first step is simple; create entity classes that model the database tables my app will be using. I plan on using annotations. Should I create a jar that contains just these enity classes? Is this the ejb-jar module (sometimes referred to as the Java module)? Next, I'll need some business logic classes that make use of the entity classes. These are the session beans (stateless or stateful) correct? Should these be packaged in the same jar as the entity classes or a separate jar? Finally, I'll need some sort of web interface (I'll be creating a JSF portlet) application that makes use of the both the session and entity beans. Together with the above jar(s), this will be my war? Assuming the above to be correct, what is involved in creating an ear? Forgive me if this post is vague, but I'm having a hard time defining what it is I don't understand. Thanks for any help!

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Best practices for (over)using Azure queues

- by John

Hi, I'm in the early phases of designing an Azure-based application. One of the things that attracts me to Azure is the scalability, given the variability of the demand I'm likely to expect. As such I'm trying to keep things loosely coupled so I can add instances when I need to. The recommendations I've seen for architecting an application for Azure include keeping web role logic to a minimum, and having processing done in worker roles, using queues to communicate and some sort of back-end store like SQL Azure or Azure Tables. This seems like a good idea to me as I can scale up either or both parts of the application without any issue. However I'm curious if there are any best practices (or if anyone has any experiences) for when it's best to just have the web role talk directly to the data store vs. sending data by the queue? I'm thinking of the case where I have a simple insert to do from the web role - while I could set this up as a message, send it on the queue, and have a worker role pick it up and do the insert, it seems like a lot of double-handling. However I also appreciate that it may be the case that this is better in the long run, in case the web role gets overwhelmed or more complex logic ends up being required for the insert. I realise this might be a case where the answer is "it depends entirely on the situation, check your perf metrics" - but if anyone has any thoughts I'd be very appreciative! Thanks John

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architecture - centraled location for different modules (cms, webapplications, ...) - best practise

- by NicoJuicy

Let's just say that i want to create a cms + other online applications. I want them all to integrate into a central location, but they also have to be available seperately (not everyone want's more than the cms solution). Would i create a huge central application that contains all the database, which communicates through a webserice with the "standalone - integrated" modules? Or would i create them seperately and the only thing that the "central" application would do is syncing the information (eg. the cms and another solution can have the same tables (eg. clients or employees). Or do you have another idea? (i know i'm a little vague, but i can't "give" a lot of details because of work - contract). If someone has all the "packages" it should be possible for the central application to integrate all the modules at one place! Or if someone has more than 1 module, it should combine this on the website. What i thought is best, is that the central location contains only the users and their rights (eg. cms - all rights, ...), and the information get synced with every change. (module cms, adding a new client - store locally and send data to the central location, central location - send to modules = table clients updated everywhere) This way it is easy if someone only "bought" a module, they can sync it easily through the complete architecture. I hope i made myself clear!

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How to fix this simple SQL query?

- by morpheous

I have a database with three tables: user_table country_table city_table I want to write ANSI SQL which will allow me to fetch all the user data (i.e. user details including the name of the country of the last school and the name of the city they live in now). The problem I am having is that I have to use a self join, and I am getting slightly confused. The schema is shown below: CREATE TABLE user_table (id int, first_name varchar(16), last_school_country_id int, city_id int); CREATE TABLE country_table (id int, name varchar(32)); CREATE TABLE city_table (id int, country_id int, name varchar(32)); This is the query I have come up with so far, but the results are wrong, and sometimes, the db engine (mySQL), asks me if I want to show all [HUGE NUMBER HERE] results - which makes me suspect that I am unintentionally creating a cartesian product somewhere. Can someone explain what is wrong with this SQL statement, and what I need to do to fix it? SELECT usr.id AS id, usr.first_name, ctry1.name as loc_country_name, ctry2.name as school_country_name, city.name as loc_city_name FROM user_table usr, country_table ctry1, country_table ctry2, city_table city WHERE usr.last_school_country_id=ctry2.id AND usr.city_id=city.id AND city.country_id=ctry1.id AND ctry1.id=ctry2.id;

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Query returning related assets

- by GMo

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Iteration over a linq to sql query is very slow.

- by devzero

I have a view, AdvertView in my database, this view is a simple join between some tables (advert, customer, properties). Then I have a simple linq query to fetch all adverts for a customer: public IEnumerable<AdvertView> GetAdvertForCustomerID(int customerID) { var advertList = from advert in _dbContext.AdvertViews where advert.Customer_ID.Equals(customerID) select advert; return advertList; } I then wish to map this to modelItems for my MVC application: public List<AdvertModelItem> GetAdvertsByCustomer(int customerId) { List<AdvertModelItem> lstAdverts = new List<AdvertModelItem>(); List<AdvertView> adViews = _dataHandler.GetAdvertForCustomerID(customerId).ToList(); foreach(AdvertView adView in adViews) { lstAdverts.Add(_advertMapper.MapToModelClass(adView)); } return lstAdverts; } I was expecting to have some performance issues with the SQL, but the problem seems to be with the .ToList() function. I'm using ANTS performance profiler and it reports that the total runtime of the function is 1.400ms, and 850 of those is with the ToList(). So my question is, why does the tolist function take such a long time here?

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Forming triangles from points and relations

- by SiN

Hello, I want to generate triangles from points and optional relations between them. Not all points form triangles, but many of them do. In the initial structure, I've got a database with the following tables: Nodes(id, value) Relations(id, nodeA, nodeB, value) Triangles(id, relation1_id, relation2_id, relation3_id) In order to generate triangles from both nodes and relations table, I've used the following query: INSERT INTO Triangles SELECT t1.id, t2.id , t3.id, FROM Relations t1, Relations t2, Relations t3 WHERE t1.id < t2.id AND t3.id > t1.id AND ( t1.nodeA = t2.nodeA AND (t3.nodeA = t1.nodeB AND t3.nodeB = t2.nodeB OR t3.nodeA = t2.nodeB AND t3.nodeB = t1.nodeB) OR t1.nodeA = t2.nodeB AND (t3.nodeA = t1.nodeB AND t3.nodeB = t2.nodeA OR t3.nodeA = t2.nodeA AND t3.nodeB = t1.nodeB) ) It's working perfectly on small sized data. (~< 50 points) In some cases however, I've got around 100 points all related to each other which leads to thousands of relations. So when the expected number of triangles is in the hundreds of thousands, or even in the millions, the query might take several hours. My main problem is not in the select query, while I see it execute in Management Studio, the returned results slow. I received around 2000 rows per minute, which is not acceptable for my case. As a matter of fact, the size of operations is being added up exponentionally and that is terribly affecting the performance. I've tried doing it as a LINQ to object from my code, but the performance was even worse. I've also tried using SqlBulkCopy on a reader from C# on the result, also with no luck. So the question is... Any ideas or workarounds?

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ASP.Net MVC - how can I easily serialize query results to a database?

- by Mortanis

I've been working on a little property search engine while I learn ASP.Net MVC. I've gotten the results from various property database tables and sorted them into a master generic property response. The search form is passed via Model Binding and works great. Now, I'd like to add pagination. I'm returning the chunk of properties for the current page with .Skip() and .Take(), and that's working great. I have a SearchResults model that has the paged result set and various other data like nextPage and prevPage. Except, I no longer have the original form of course to pass to /Results/2. Previously I'd have just hidden a copy of the form and done a POST each time, but it seems inelegant. I'd like to serialize the results to my MS SQL database and return a unique key for that results set - this also helps with a "Send this query to a friend!" link. Killing two birds with one stone. Is there an easy way to take an IQueryable result set that I have, serialize it, stick it into the DB, return a unique key and then reverse the process with said key? I'm using Linq to SQL currently on a MS SQL Express install, though in production it'll be on MS SQL 2008.

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Self organizing layouts

- by user613326

Quite a while ago i was more in websites building then i am now. In my time there where huge debates about what to use; tables or pure CSS alternatives. I went out of the webdesigning, but now an old question re-surfaces. What i would like to create is a web page design that depending on screensize, would self organize the page into columns, so that for example on a PDA it would show 1 column On an old computer monitor, it would show 2 colomns, and on a widescreen laptop it would show 3 columns. I forgot how this was called and how it was done in the past, it had to do with XML and storing data seperate from design (if i remember well), perhaps these days better methods exist to do that, does this, anyone ring this a bell ? Also i note a lot is possible with Jquery and and brouwser depending webkits. But i need to make sure that it would run on all (modern) brouwsers : Iexplorer, Firefox, chrome And Jquery is nice too, but i am kinda woried that some day one of these brouwser vendors decides that jscript like java isnt enabled by default (or is that very unlikely ?)11 Perhaps someone can point me to a method that is the prefered way to do this.

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Entity Framework 1:1 Relationship Identity Colums

- by Hupperware

I cannot for the life of me get two separate tables to save with a relationship and two identity columns. I keep getting errors like A dependent property in a ReferentialConstraint is mapped to a store-generated column. Column: 'OlsTerminalId'. I can't imagine that this setup is abnormal. [DataContract] public class OlsData { private static readonly DateTime theUnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc); [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int OlsDataId { get; set; } [DataMember(Name = "id")] public int Id { get; set; } public DateTime Timestamp { get; set; } [DataMember(Name = "created")] [NotMapped] public double Created { get { return (Timestamp - theUnixEpoch).TotalMilliseconds; } set { Timestamp = theUnixEpoch.AddMilliseconds(value); } } [InverseProperty("OlsData")] [DataMember(Name = "terminal")] public virtual OlsTerminal OlsTerminal { get; set; } } [DataContract] public class OlsTerminal { [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int OlsTerminalId { get; set; } public int OlsDataId { get; set; } [DataMember(Name = "account")] [NotMapped] public virtual OlsAccount OlsAccount { get; set; } [DataMember(Name = "terminalId")] public string TerminalId { get; set; } [DataMember(Name = "merchantId")] public string MerchantId { get; set; } public virtual OlsData OlsData { get; set; } } public class OlsDataContext : DbContext { protected override void OnModelCreating(DbModelBuilder aModelBuilder) { aModelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); } public OlsDataContext(string aConnectionString) : base(aConnectionString) {} public DbSet<OlsData> OlsData { get; set; } public DbSet<OlsTerminal> OlsTerminal { get; set; } public DbSet<OlsAccount> OlsAccount { get; set; } }

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