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• redoing object model construction to fit with asynchronous data fetching

  - by Andrew Patterson

  I have a modeled a set of objects that correspond with some real world concepts. TradeDrug, GenericDrug, TradePackage, DrugForm Underlying the simple object model I am trying to provide is a complex medical terminology that uses numeric codes to represent relationships and concepts, all accessible via a REST service - I am trying to hide away some of that complexity with an object wrapper. To give a concrete example I can call TradeDrug d = Searcher.FindTradeDrug("Zoloft") or TradeDrug d = new TradeDrug(34) where 34 might be the code for Zoloft. This will consult a remote server to find out some details about Zoloft. I might then call GenericDrug generic = d.EquivalentGeneric() System.Out.WriteLine(generic.ActiveIngredient().Name) in order to get back the generic drug sertraline as an object (again via a background REST call to the remote server that has all these drug details), and then perhaps find its ingredient. This model works fine and is being used in some applications that involve data processing. Recently however I wanted to do a silverlight application that used and displayed these objects. The silverlight environment only allows asynchronous REST/web service calls. I have no problems with how to make the asychhronous calls - but I am having trouble with what the design should be for my object construction. Currently the constructors for my objects do some REST calls sychronously. public TradeDrug(int code) { form = restclient.FetchForm(code) name = restclient.FetchName(code) etc.. } If I have to use async 'events' or 'actions' in order to use the Silverlight web client (I know silverlight can be forced to be a synchronous client but I am interested in asychronous approaches), does anyone have an guidance or best practice for how to structure my objects. I can pass in an action callback to the constructor public TradeDrug(int code, Action<TradeDrug> constructCompleted) { } but this then allows the user to have a TradeDrug object instance before what I want to construct is actually finished. It also doesn't support an 'event' async pattern because the object doesn't exist to add the event to until it is constructed. Extending that approach might be a factory object that itself has an asynchronous interface to objects factory.GetTradeDrugAsync(code, completedaction) or with a GetTradeDrugCompleted event? Does anyone have any recommendations?

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• Decompressing a very large serialized object and managing memory

  - by Mike_G

  I have an object that contains tons of data used for reports. In order to get this object from the server to the client I first serialize the object in a memory stream, then compress it using the Gzip stream of .NET. I then send the compressed object as a byte[] to the client. The problem is on some clients, when they get the byte[] and try to decompress and deserialize the object, a System.OutOfMemory exception is thrown. Ive read that this exception can be caused by new() a bunch of objects, or holding on to a bunch of strings. Both of these are happening during the deserialization process. So my question is: How do I prevent the exception (any good strategies)? The client needs all of the data, and ive trimmed down the number of strings as much as i can. edit: here is the code i am using to serialize/compress (implemented as extension methods) public static byte[] SerializeObject<T>(this object obj, T serializer) where T: XmlObjectSerializer { Type t = obj.GetType(); if (!Attribute.IsDefined(t, typeof(DataContractAttribute))) return null; byte[] initialBytes; using (MemoryStream stream = new MemoryStream()) { serializer.WriteObject(stream, obj); initialBytes = stream.ToArray(); } return initialBytes; } public static byte[] CompressObject<T>(this object obj, T serializer) where T : XmlObjectSerializer { Type t = obj.GetType(); if(!Attribute.IsDefined(t, typeof(DataContractAttribute))) return null; byte[] initialBytes = obj.SerializeObject(serializer); byte[] compressedBytes; using (MemoryStream stream = new MemoryStream(initialBytes)) { using (MemoryStream output = new MemoryStream()) { using (GZipStream zipper = new GZipStream(output, CompressionMode.Compress)) { Pump(stream, zipper); } compressedBytes = output.ToArray(); } } return compressedBytes; } internal static void Pump(Stream input, Stream output) { byte[] bytes = new byte[4096]; int n; while ((n = input.Read(bytes, 0, bytes.Length)) != 0) { output.Write(bytes, 0, n); } } And here is my code for decompress/deserialize: public static T DeSerializeObject<T,TU>(this byte[] serializedObject, TU deserializer) where TU: XmlObjectSerializer { using (MemoryStream stream = new MemoryStream(serializedObject)) { return (T)deserializer.ReadObject(stream); } } public static T DecompressObject<T, TU>(this byte[] compressedBytes, TU deserializer) where TU: XmlObjectSerializer { byte[] decompressedBytes; using(MemoryStream stream = new MemoryStream(compressedBytes)) { using(MemoryStream output = new MemoryStream()) { using(GZipStream zipper = new GZipStream(stream, CompressionMode.Decompress)) { ObjectExtensions.Pump(zipper, output); } decompressedBytes = output.ToArray(); } } return decompressedBytes.DeSerializeObject<T, TU>(deserializer); } The object that I am passing is a wrapper object, it just contains all the relevant objects that hold the data. The number of objects can be a lot (depending on the reports date range), but ive seen as many as 25k strings. One thing i did forget to mention is I am using WCF, and since the inner objects are passed individually through other WCF calls, I am using the DataContract serializer, and all my objects are marked with the DataContract attribute.

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• How to do an fetch request with expressions like this on the iPhone?

  - by dontWatchMyProfile

  The documentation has an example on how to retrieve simple values only, rather than managed objects. This remembers a lot SQL using aliases and functions to only retrieve calculated values. So, actually pretty geeky stuff. To get the minimum date from a bunch of records, this is used on the mac: NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:context]; [request setEntity:entity]; // Specify that the request should return dictionaries. [request setResultType:NSDictionaryResultType]; // Create an expression for the key path. NSExpression *keyPathExpression = [NSExpression expressionForKeyPath:@"creationDate"]; // Create an expression to represent the minimum value at the key path 'creationDate' NSExpression *minExpression = [NSExpression expressionForFunction:@"min:" arguments:[NSArray arrayWithObject:keyPathExpression]]; // Create an expression description using the minExpression and returning a date. NSExpressionDescription *expressionDescription = [[NSExpressionDescription alloc] init]; // The name is the key that will be used in the dictionary for the return value. [expressionDescription setName:@"minDate"]; [expressionDescription setExpression:minExpression]; [expressionDescription setExpressionResultType:NSDateAttributeType]; // Set the request's properties to fetch just the property represented by the expressions. [request setPropertiesToFetch:[NSArray arrayWithObject:expressionDescription]]; // Execute the fetch. NSError *error; NSArray *objects = [managedObjectContext executeFetchRequest:request error:&error]; if (objects == nil) { // Handle the error. } else { if ([objects count] > 0) { NSLog(@"Minimum date: %@", [[objects objectAtIndex:0] valueForKey:@"minDate"]; } } [expressionDescription release]; [request release]; Nice, I though - but having a deep look into NSExpression -expressionForFunction:arguments: it turns out that iPhone OS does NOT support the min: function. Well, probably there's a nifty way to use an own function for this kind of stuff on the iPhone as well? Because on thing I'm already worrying about is, how I'm gonna sort a table based on the calculated distance of targets on a map (location-based stuff).

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• G++, compiler warnings, c++ templates

  - by Ian

  During the compilatiion of the C++ program those warnings appeared: c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_algo.h:2317: instantiated from `void std::partial_sort(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Object<double>**, std::vector<Object<double>*, std::allocator<Object<double>*> > >, _Compare = sortObjects<double>]' c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_algo.h:2506: instantiated from `void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Object<double>**, std::vector<Object<double>*, std::allocator<Object<double>*> > >, _Size = int, _Compare = sortObjects<double>]' c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_algo.h:2589: instantiated from `void std::sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Object<double>**, std::vector<Object<double>*, std::allocator<Object<double>*> > >, _Compare = sortObjects<double>]' io/../structures/objects/../../algorithm/analysis/../../structures/list/ObjectsList.hpp:141: instantiated from `void ObjectsList <T>::sortObjects(unsigned int, T, T, T, T, unsigned int) [with T = double]' I do not why, because all objects have only template parameter T, their local variables are also T. The only place, where I am using double is main. There are objects of type double creating and adding into the ObjectsList... Object <double> o1; ObjectsList <double> olist; olist.push_back(o1); .... T xmin = ..., ymin = ..., xmax = ..., ymax = ...; unsigned int n = ...; olist.sortAllObjects(xmin, ymin, xmax, ymax, n); and comparator template <class T> class sortObjects { private: unsigned int n; T xmin, ymin, xmax, ymax; public: sortObjects ( const T xmin_, const T ymin_, const T xmax_, const T ymax_, const int n_ ) : xmin ( xmin_ ), ymin ( ymin_ ), xmax ( xmax_ ), ymax ( ymax_ ), n ( n_ ) {} bool operator() ( const Object <T> *o1, const Object <T> *o2 ) const { T dmax = (std::max) ( xmax - xmin, ymax - ymin ); T x_max = ( xmax - xmin ) / dmax; T y_max = ( ymax - ymin ) / dmax; ... return ....; } representing ObjectsList method: template <class T> void ObjectsList <T> ::sortAllObjects ( const T xmin, const T ymin, const T xmax, const T ymax, const unsigned int n ) { std::sort ( objects.begin(), objects.end(), sortObjects <T> ( xmin, ymin, xmax, ymax, n ) ); }

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• Wondering about a way to conserve memory in C# using List<> with structs

  - by Michael Ryan

  I'm not even sure how I should phrase this question. I'm passing some CustomStruct objects as parameters to a class method, and storing them in a List. What I'm wondering is if it's possible and more efficient to add multiple references to a particular instance of a CustomStruct if a equivalent instance it found. This is a dummy/example struct: public struct CustomStruct { readonly int _x; readonly int _y; readonly int _w; readonly int _h; readonly Enum _e; } Using the below method, you can pass one, two, or three CustomStruct objects as parameters. In the final method (that takes three parameters), it may be the case that the 3rd and possibly the 2nd will have the same value as the first. List<CustomStruct> _list; public void AddBackground(CustomStruct normal) { AddBackground(normal, normal, normal); } public void AddBackground(CustomStruct normal, CustomStruct hover) { AddBackground(normal, hover, hover); } public void AddBackground(CustomStruct normal, CustomStruct hover, CustomStruct active) { _list = new List<CustomStruct>(3); _list.Add(normal); _list.Add(hover); _list.Add(active); } As the method stands now, I believe it will create new instances of CustomStruct objects, and then adds a reference of each to the List. It is my understanding that if I instead check for equality between normal and hover and (if equal) insert normal again in place of hover, when the method completes, hover will lose all references and eventually be garbage collected, whereas normal will have two references in the List. The same could be done for active. That would be better, right? The CustomStruct is a ValueType, and therefore one instance would remain on the Stack, and the three List references would just point to it. The overall List size is determined not by the object Type is contains, but by its Capacity. By eliminating the "duplicate" CustomStuct objects, you allow them to be cleaned up. When the CustomStruct objects are passed to these methods, new instances are created each time. When the structs are added to the List, is another copy made? For example, if i pass just one CustomStruct, AddBackground(normal) creates a copy of the original variable, and then passes it three times to Addbackground(normal, hover, active). In this method, three copies are made of the original copy. When the three local variables are added to the List using Add(), are additional copies created inside Add(), and does that defeat the purpose of any equality checks as previously mentioned? Am I missing anything here?

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• should I ever put a major version number into a C#/Java namespace?

  - by Andrew Patterson

  I am designing a set of 'service' layer objects (data objects and interface definitions) for a WCF web service (that will be consumed by third party clients i.e. not in-house, so outside my direct control). I know that I am not going to get the interface definition exactly right - and am wanting to prepare for the time when I know that I will have to introduce a breaking set of new data objects. However, the reality of the world I am in is that I will also need to run my first version simultaneously for quite a while. The first version of my service will have URL of http://host/app/v1service.svc and when the times comes by new version will live at http://host/app/v2service.svc However, when it comes to the data objects and interfaces, I am toying with putting the 'major' version of the interface number into the actual namespace of the classes. namespace Company.Product.V1 { [DataContract(Namespace = "company-product-v1")] public class Widget { [DataMember] string widgetName; } public interface IFunction { Widget GetWidgetData(int code); } } When the time comes for a fundamental change to the service, I will introduce some classes like namespace Company.Product.V2 { [DataContract(Namespace = "company-product-v2")] public class Widget { [DataMember] int widgetCode; [DataMember] int widgetExpiry; } public interface IFunction { Widget GetWidgetData(int code); } } The advantages as I see it are that I will be able to have a single set of code serving both interface versions, sharing functionality where possible. This is because I will be able to reference both interface versions as a distinct set of C# objects. Similarly, clients may use both interface versions simultaneously, perhaps using V1.Widget in some legacy code whilst new bits move on to V2.Widget. Can anyone tell why this is a stupid idea? I have a nagging feeling that this is a bit smelly.. notes: I am obviously not proposing every single new version of the service would be in a new namespace. Presumably I will do as many non-breaking interface changes as possible, but I know that I will hit a point where all the data modelling will probably need a significant rewrite. I understand assembly versioning etc but I think this question is tangential to that type of versioning. But I could be wrong.

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• LINQ Query Returning Multiple Copies Of First Result

  - by Mike G

  I'm trying to figure out why a simple query in LINQ is returning odd results. I have a view defined in the database. It basically brings together several other tables and does some data munging. It really isn't anything special except for the fact that it deals with a large data set and can be a bit slow. I want to query this view based on a long. Two sample queries below show different queries to this view. var la = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).ToList(); var deDa = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).Select(p => new { p.AccountNumber, p.SecurityNumber, p.CUSIP }).ToList(); The first one should hand back a List. The second one will be a list of anonymous objects. When I do these queries in entities framework the first one will hand me back a list of results where they're all exactly the same. The second query will hand me back data where the account number is the one that I queried and the other values differ. This seems to do this on a per account number basis, ie if I were to query for one account number or another all the Position objects for one account would have the same value (the first one in the list of Positions for that account) and the second account would have a set of Position objects that all had the same value (again, the first one in it's list of Position objects). I can write SQL that is in effect the same as either of the two EF queries. They both come back with results (say four) that show the correct data, one account number with different securities numbers. Why does this happen??? Is there something that I could be doing wrong so that if I had four results for the first query above that the first record's data also appears in the 2-4th's objects??? I cannot fathom what would/could be causing this. I've searched Google for all kinds of keywords and haven't seen anyone with this issue. We partial class out the Positions class for added functionality (smart object) and some smart properties. There are even some constructors that provide some view model type support. None of this is invoked in the request (I'm 99% sure of this). However, we do this same pattern all over the app. The only thing I can think of is that the mapping in the EDMX is screwy. Is there a way that this would happen if the "primary keys" in the EDMX were not in fact unique given the way the view is constructed? I'm thinking that the dev who imported this model into the EDMX let the designer auto select what would be unique. Any help would give a haggered dev some hope!

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• How can I modify my classes to use it's collections in WPF TreeView

  - by Victor

  Hello, i'am trying to modify my objects to make hierarchical collection model. I need help. My objects are Good and GoodCategory: public class Good { int _ID; int _GoodCategory; string _GoodtName; public int ID { get { return _ID; } } public int GoodCategory { get { return _GoodCategory; } set { _GoodCategory = value; } } public string GoodName { get { return _GoodName; } set { _GoodName = value; } } public Good(IDataRecord record) { _ID = (int)record["ID"]; _GoodtCategory = (int)record["GoodCategory"]; } } public class GoodCategory { int _ID; string _CategoryName; public int ID { get { return _ID; } } public string CategoryName { get { return _CategoryName; } set { _CategoryName = value; } } public GoodCategory(IDataRecord record) { _ID = (int)record["ID"]; _CategoryName = (string)record["CategoryName"]; } } And I have two Collections of these objects: public class GoodsList : ObservableCollection<Good> { public GoodsList() { string goodQuery = @"SELECT `ID`, `ProductCategory`, `ProductName`, `ProductFullName` FROM `products`;"; using (MySqlConnection conn = ConnectToDatabase.OpenDatabase()) { if (conn != null) { MySqlCommand cmd = conn.CreateCommand(); cmd.CommandText = productQuery; MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Add(new Good(rdr)); } } } } } public class GoodCategoryList : ObservableCollection<GoodCategory> { public GoodCategoryList () { string goodQuery = @"SELECT `ID`, `CategoryName` FROM `product_categoryes`;"; using (MySqlConnection conn = ConnectToDatabase.OpenDatabase()) { if (conn != null) { MySqlCommand cmd = conn.CreateCommand(); cmd.CommandText = productQuery; MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Add(new GoodCategory(rdr)); } } } } } So I have two collections which takes data from the database. But I want to use thats collections in the WPF TreeView with HierarchicalDataTemplate. I saw many post's with examples of Hierarlichal Objects, but I steel don't know how to make my objects hierarchicaly. Please help.

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• LINQ Except operator and object equality

  - by Abhijeet Patel

  Here is an interesting issue I noticed when using the Except Operator: I have list of users from which I want to exclude some users: The list of users is coming from an XML file: The code goes like this: interface IUser { int ID { get; set; } string Name { get; set; } } class User: IUser { #region IUser Members public int ID { get; set; } public string Name { get; set; } #endregion public override string ToString() { return ID + ":" +Name; } public static IEnumerable<IUser> GetMatchingUsers(IEnumerable<IUser> users) { IEnumerable<IUser> localList = new List<User> { new User{ ID=4, Name="James"}, new User{ ID=5, Name="Tom"} }.OfType<IUser>(); var matches = from u in users join lu in localList on u.ID equals lu.ID select u; return matches; } } class Program { static void Main(string[] args) { XDocument doc = XDocument.Load("Users.xml"); IEnumerable<IUser> users = doc.Element("Users").Elements("User").Select (u => new User { ID = (int)u.Attribute("id"), Name = (string)u.Attribute("name") } ).OfType<IUser>(); //still a query, objects have not been materialized var matches = User.GetMatchingUsers(users); var excludes = users.Except(matches); // excludes should contain 6 users but here it contains 8 users } } When I call User.GetMatchingUsers(users) I get 2 matches as expected. The issue is that when I call users.Except(matches) The matching users are not being excluded at all! I am expecting 6 users ut "excludes" contains all 8 users instead. Since all I'm doing in GetMatchingUsers(IEnumerable users) is taking the IEnumerable and just returning the IUsers whose ID's match( 2 IUsers in this case), my understanding is that by default "Except" will use reference equality for comparing the objects to be excluded. Is this not how "Except" behaves? What is even more interesting is that if I materialize the objects using .ToList() and then get the matching users, and call "Except", everything works as expected! Like so: IEnumerable users = doc.Element("Users").Elements("User").Select (u = new User { ID = (int)u.Attribute("id"), Name = (string)u.Attribute("name") } ).OfType().ToList(); //explicity materializing all objects by calling ToList() var matches = User.GetMatchingUsers(users); var excludes = users.Except(matches); // excludes now contains 6 users as expected I don't see why I should need to materialize objects for calling "Except" given that its defined on IEnumerable? Any suggesstions / insights would be much appreciated.

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• EXC_MEMORY_ACCESS when trying to delete from Core Data ($cash solution)

  - by llloydxmas

  I have an application that downloads an xml file, parses the file, and creates core data objects while doing so. In the parse code I have a function called 'emptydatacontext' that removes all items from Core Data before creating replacements items from the xml data. This method looks like this: -(void) emptyDataContext { NSFetchRequest * allCon = [[NSFetchRequest alloc] init]; [allCon setEntity:[NSEntityDescription entityForName:@"Condition" inManagedObjectContext:managedObjectContext]]; NSError * error = nil; NSArray * conditions = [managedObjectContext executeFetchRequest:allCon error:&error]; DebugLog(@"ERROR: %@",error); DebugLog(@"RETRIEVED: %@", conditions); [allCon release]; for (NSManagedObject * condition in conditions) { [managedObjectContext deleteObject:condition]; } // Update the data model effectivly removing the objects we removed above. //NSError *error; if (![managedObjectContext save:&error]) { DebugLog(@"%@", [error domain]); } } The first time this runs it deletes all objects and functions as it should - creating new objects from the xml file. I created a 'update' button that starts the exact same process of retrieving the file the proceeding with the parse & build. All is well until its time to delete the core data objects. This 'deleteObject' call creates a "EXC_BAD_ACCESS" error each time. This only happens on the second time through. Captured errors return null. If I log the 'conditions' array I get a list of NSManagedObjects on the first run. On the second this log request causes a crash exactly as the deleteObject call does. I have a feeling it is something very simple I'm missing or not doing correctly to cause this behavior. The data works great on my tableviews - its only when trying to update I get the crashes. I have spent days & days on this trying numerous alternative methods. Whats left of my hair is falling out. I'd be willing to ante up some cash for anyone willing to look at my code and see what I'm doing wrong. Just need to get past this hurdle. Thanks in advance for the help!

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• What web platform is right for me?

  - by egervari

  I've been looking at web frameworks like Rails, Grails, etc. I'm used to doing applications in Spring Framework with Hibernate... and I want something more productive. One of the things I realized is that while some of the things in Grails is sexy, there are some serious problems with it. Grails' controllers: 1) are implemented awfully. They don't seem to be able to extend from super classes at runtime. I tried this to add base actions and helper methods, and this seems to cause grails to blow up. 2) are based on an obsolete request parameters model (rather than form backing objects, which are much nicer). 3) are hard to test. Command objects are treated totally differently... and it's actually MUCH harder to write the test than it is to write the controller code. 4) Command objects operate totally differently. They are pre-validated and bound, which causes a lot of inconsistencies than basic parameter model. 5) Command objects are not reusable, and it's a pain in the rear to reuse most of the stuff from the domain classes, like constraints and fields. This is TRIVIAL to do in basic Spring. Why the hell was it not trivial to do in Grails? 6) The scaffolding that is generated is pure crap. It doesn't generalize inserts and updates... and it actually copy/pastes a pile of code in two views: create.gsp and edit.gsp. The views themselves are gargantuan piles of doggie do-do. This is further compounded by the fact that it uses low-level parameters and not objects. Integration tests are 30x slower than a Spring integration test. It is disgusting. Some mocking tests are so hard to write and aren't guaranteed to work when it's deployed, that I think it discourages fast, tdd test cycles. Most things seem to screw up grails while it's running, like adding a taglib, or anything really. The server restart problem wasn't solved at all. I'm starting to think going with Spring/Hibernate/Java is the only way to go. While there is a pretty big cost at startup, I know it'll eventually smooth out. It sucks I can't use a language like Scala... because idiomatically, it is so incompatible with Hibernate. This app is also not a run-of-the-mill UI over a database. It's got some of that, but it's not going to be a slouch. I am deathly scared of Grails now because of how crap it is in the Controller layer. Suggestions on what I can do?

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• nodejs async.waterfall method

  - by user1513388

  Update 2 Complete code listing var request = require('request'); var cache = require('memory-cache'); var async = require('async'); var server = '172.16.221.190' var user = 'admin' var password ='Passw0rd' var dn ='\\VE\\Policy\\Objects' var jsonpayload = {"Username": user, "Password": password} async.waterfall([ //Get the API Key function(callback){ request.post({uri: 'http://' + server +'/sdk/authorize/', json: jsonpayload, headers: {'content_type': 'application/json'} }, function (e, r, body) { callback(null, body.APIKey); }) }, //List the credential objects function(apikey, callback){ var jsonpayload2 = {"ObjectDN": dn, "Recursive": true} request.post({uri: 'http://' + server +'/sdk/Config/enumerate?apikey=' + apikey, json: jsonpayload2, headers: {'content_type': 'application/json'} }, function (e, r, body) { var dns = []; for (var i = 0; i < body.Objects.length; i++) { dns.push({'name': body.Objects[i].Name, 'dn': body.Objects[i].DN}) } callback(null, dns, apikey); }) }, function(dns, apikey, callback){ // console.log(dns) var cb = []; for (var i = 0; i < dns.length; i++) { //Retrieve the credential var jsonpayload3 = {"CredentialPath": dns[i].dn, "Pattern": null, "Recursive": false} console.log(dns[i].dn) request.post({uri: 'http://' + server +'/sdk/credentials/retrieve?apikey=' + apikey, json: jsonpayload3, headers: {'content_type': 'application/json'} }, function (e, r, body) { // console.log(body) cb.push({'cl': body.Classname}) callback(null, cb, apikey); console.log(cb) }); } } ], function (err, result) { // console.log(result) // result now equals 'done' }); Update: I'm building a small application that needs to make multiple HTTP calls to a an external API and amalgamates the results into a single object or array. e.g. Connect to endpoint and get auth key - pass auth key to step 2 Connect to endpoint using auth key and get JSON results - create an object containing summary results and pass to step 3. Iterate over passed object summary results and call API for each item in the object to get detailed information for each summary line Create a single JSON data structure that contains the summary and detail information. The original question below outlines what I've tried so far! Original Question: Will the async.waterfall method support multiple callbacks? i.e. Iterate over an array thats passed from a previous item in the chain, then invoke multiple http requests each of which would have their own callbacks. e.g, sync.waterfall([ function(dns, key, callback){ var cb = []; for (var i = 0; i < dns.length; i++) { //Retrieve the credential var jsonpayload3 = {"Cred": dns[i].DN, "Pattern": null, "Recursive": false} console.log(dns[i].DN) request.post({uri: 'http://' + vedserver +'/api/cred/retrieve?apikey=' + key, json: jsonpayload3, headers: {'content_type': 'application/json'} }, function (e, r, body) { console.log(body) cb.push({'cl': body.Classname}) callback(null, cb, key); }); } }

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• Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

  - by Eye of Hell

  Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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• Java Flow Control Problem

  - by Kyle_Solo

  I am programming a simple 2d game engine. I've decided how I'd like the engine to function: it will be composed of objects containing "events" that my main game loop will trigger when appropriate. A little more about the structure: Every GameObject has an updateEvent method. objectList is a list of all the objects that will receive update events. Only objects on this list have their updateEvent method called by the game loop. I’m trying to implement this method in the GameObject class (This specification is what I’d like the method to achieve): /** * This method removes a GameObject from objectList. The GameObject * should immediately stop executing code, that is, absolutely no more * code inside update events will be executed for the removed game object. * If necessary, control should transfer to the game loop. * @param go The GameObject to be removed */ public void remove(GameObject go) So if an object tries to remove itself inside of an update event, control should transfer back to the game engine: public void updateEvent() { //object's update event remove(this); System.out.println("Should never reach here!"); } Here’s what I have so far. It works, but the more I read about using exceptions for flow control the less I like it, so I want to see if there are alternatives. Remove Method public void remove(GameObject go) { //add to removedList //flag as removed //throw an exception if removing self from inside an updateEvent } Game Loop for(GameObject go : objectList) { try { if (!go.removed) { go.updateEvent(); } else { //object is scheduled to be removed, do nothing } } catch(ObjectRemovedException e) { //control has been transferred back to the game loop //no need to do anything here } } // now remove the objects that are in removedList from objectList 2 questions: Am I correct in assuming that the only way to implement the stop-right-away part of the remove method as described above is by throwing a custom exception and catching it in the game loop? (I know, using exceptions for flow control is like goto, which is bad. I just can’t think of another way to do what I want!) For the removal from the list itself, it is possible for one object to remove one that is farther down on the list. Currently I’m checking a removed flag before executing any code, and at the end of each pass removing the objects to avoid concurrent modification. Is there a better, preferably instant/non-polling way to do this?

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• Hibernate/Spring: getHibernateTemplate().save(...) Freezes/Hangs

  - by ashes999

  I'm using Hibernate and Spring with the DAO pattern (all Hibernate dependencies in a *DAO.java class). I have nine unit tests (JUnit) which create some business objects, save them, and perform operations on them; the objects are in a hash (so I'm reusing the same objects all the time). My JUnit setup method calls my DAO.deleteAllObjects() method which calls getSession().createSQLQuery("DELETE FROM <tablename>").executeUpdate() for my business object table (just one). One of my unit tests (#8/9) freezes. I presumed it was a database deadlock, because the Hibernate log file shows my delete statement last. However, debugging showed that it's simply HibernateTemplate.save(someObject) that's freezing. (Eclipse shows that it's freezing on HibernateTemplate.save(Object), line 694.) Also interesting to note is that running this test by itself (not in the suite of 9 tests) doesn't cause any problems. How on earth do I troubleshoot and fix this? Also, I'm using @Entity annotations, if that matters. Edit: I removed reuse of my business objects (use unique objects in every method) -- didn't make a difference (still freezes). Edit: This started trickling into other tests, too (can't run more than one test class without getting something freezing) Transaction configuration: <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <tx:advice id="txAdvice" transaction-manager="txManager"> <!-- the transactional semantics... --> <tx:attributes> <!-- all methods starting with 'get' are read-only --> <tx:method name="get*" read-only="true" /> <tx:method name="find*" read-only="true" /> <!-- other methods use the default transaction settings (see below) --> <tx:method name="*" /> </tx:attributes> </tx:advice> <!-- my bean which is exhibiting the hanging behavior --> <aop:config> <aop:pointcut id="beanNameHere" expression="execution(* com.blah.blah.IMyDAO.*(..))" /> <aop:advisor advice-ref="txAdvice" pointcut-ref="beanNameHere" /> </aop:config>

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• Squid w/ SquidGuard fails w/ "Too few redirector processes are running"

  - by DKNUCKLES

  I'm trying to implement a Squid proxy in a quick and easy fashion and I'm receiving some errors I have been unable to resolve. The box is a pre-made appliance, however it seems to fail on launch.The following is the cache.log file when I attempt to launch the squid service. 2012/11/18 22:14:29| Starting Squid Cache version 3.0.STABLE20-20091201 for i686 -pc-linux-gnu... 2012/11/18 22:14:29| Process ID 12647 2012/11/18 22:14:29| With 1024 file descriptors available 2012/11/18 22:14:29| Performing DNS Tests... 2012/11/18 22:14:29| Successful DNS name lookup tests... 2012/11/18 22:14:29| DNS Socket created at 0.0.0.0, port 40513, FD 8 2012/11/18 22:14:29| Adding nameserver 192.168.0.78 from /etc/resolv.conf 2012/11/18 22:14:29| Adding nameserver 8.8.8.8 from /etc/resolv.conf 2012/11/18 22:14:29| helperOpenServers: Starting 5/5 'bin' processes 2012/11/18 22:14:29| ipcCreate: /opt/squidguard/bin: (13) Permission denied 2012/11/18 22:14:29| ipcCreate: /opt/squidguard/bin: (13) Permission denied 2012/11/18 22:14:29| ipcCreate: /opt/squidguard/bin: (13) Permission denied 2012/11/18 22:14:29| ipcCreate: /opt/squidguard/bin: (13) Permission denied 2012/11/18 22:14:29| ipcCreate: /opt/squidguard/bin: (13) Permission denied 2012/11/18 22:14:29| helperOpenServers: Starting 5/5 'squid-auth.pl' processes 2012/11/18 22:14:29| User-Agent logging is disabled. 2012/11/18 22:14:29| Referer logging is disabled. 2012/11/18 22:14:29| Unlinkd pipe opened on FD 23 2012/11/18 22:14:29| Swap maxSize 10240000 + 8192 KB, estimated 788322 objects 2012/11/18 22:14:29| Target number of buckets: 39416 2012/11/18 22:14:29| Using 65536 Store buckets 2012/11/18 22:14:29| Max Mem size: 8192 KB 2012/11/18 22:14:29| Max Swap size: 10240000 KB 2012/11/18 22:14:29| Version 1 of swap file with LFS support detected... 2012/11/18 22:14:29| Rebuilding storage in /opt/squid3/var/cache (DIRTY) 2012/11/18 22:14:29| Using Least Load store dir selection 2012/11/18 22:14:29| Set Current Directory to /opt/squid3/var/cache 2012/11/18 22:14:29| Loaded Icons. 2012/11/18 22:14:29| Accepting HTTP connections at 10.0.0.6, port 3128, FD 25. 2012/11/18 22:14:29| Accepting ICP messages at 0.0.0.0, port 3130, FD 26. 2012/11/18 22:14:29| HTCP Disabled. 2012/11/18 22:14:29| Ready to serve requests. 2012/11/18 22:14:29| Done reading /opt/squid3/var/cache swaplog (0 entries) 2012/11/18 22:14:29| Finished rebuilding storage from disk. 2012/11/18 22:14:29| 0 Entries scanned 2012/11/18 22:14:29| 0 Invalid entries. 2012/11/18 22:14:29| 0 With invalid flags. 2012/11/18 22:14:29| 0 Objects loaded. 2012/11/18 22:14:29| 0 Objects expired. 2012/11/18 22:14:29| 0 Objects cancelled. 2012/11/18 22:14:29| 0 Duplicate URLs purged. 2012/11/18 22:14:29| 0 Swapfile clashes avoided. 2012/11/18 22:14:29| Took 0.02 seconds ( 0.00 objects/sec). 2012/11/18 22:14:29| Beginning Validation Procedure 2012/11/18 22:14:29| WARNING: redirector #1 (FD 9) exited 2012/11/18 22:14:29| WARNING: redirector #2 (FD 10) exited 2012/11/18 22:14:29| WARNING: redirector #3 (FD 11) exited 2012/11/18 22:14:29| WARNING: redirector #4 (FD 12) exited 2012/11/18 22:14:29| Too few redirector processes are running FATAL: The redirector helpers are crashing too rapidly, need help! Squid Cache (Version 3.0.STABLE20-20091201): Terminated abnormally. CPU Usage: 0.112 seconds = 0.032 user + 0.080 sys Maximum Resident Size: 0 KB Page faults with physical i/o: 0 Memory usage for squid via mallinfo(): total space in arena: 2944 KB Ordinary blocks: 2857 KB 6 blks Small blocks: 0 KB 0 blks Holding blocks: 1772 KB 8 blks Free Small blocks: 0 KB Free Ordinary blocks: 86 KB Total in use: 4629 KB 157% Total free: 86 KB 3% The "permission denied" area is where I have been focusing my attention with no luck. The following is what I've tried. Chmod'ing the /opt/squidguard/bin folder to 777 Changing the user that squidguard runs under to root / nobody / www-data / squid3 Tried changing ownership of the /opt/squidguard/bin folder to all names listed above after assigning that user to run with squid. Any help with this would be greatly appreciated.

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• Measuring ASP.NET and SharePoint output cache

  - by DigiMortal

  During ASP.NET output caching week in my local blog I wrote about how to measure ASP.NET output cache. As my posting was based on real work and real-life results then I thought that this posting is maybe interesting to you too. So here you can read what I did, how I did and what was the result. Introduction Caching is not effective without measuring it. As MVP Henn Sarv said in one of his sessions then you will get what you measure. And right he is. Lately I measured caching on local Microsoft community portal to make sure that our caching strategy is good enough in environment where this system lives. In this posting I will show you how to start measuring the cache of your web applications. Although the application measured is built on SharePoint Server publishing infrastructure, all those counters have same meaning as similar counters under pure ASP.NET applications. Measured counters I used Performance Monitor and the following performance counters (their names are similar on ASP.NET and SharePoint WCMS): Total number of objects added – how much objects were added to output cache. Total object discards – how much objects were deleted from output cache. Cache hit count – how many times requests were served by cache. Cache hit ratio – percent of requests served from cache. The first three counters are cumulative while last one is coefficient. You can use also other counters to measure the full effect of caching (memory, processor, disk I/O, network load etc before and after caching). Measuring process The measuring I describe here started from freshly restarted web server. I measured application during 12 hours that covered also time ranges when users are most active. The time range does not include late evening hours and night because there is nothing to measure during these hours. During measuring we performed no maintenance or administrative tasks on server. All tasks performed were related to usual daily content management and content monitoring. Also we had no advertisement campaigns or other promotions running at same time. The results You can see the results on following graphic.   Total number of objects added   Total object discards   Cache hit count   Cache hit ratio You can see that adds and discards are growing in same tempo. It is good because cache expires and not so popular items are not kept in memory. If there are more popular content then the these lines may have bigger distance between them. Cache hit count grows faster and this shows that more and more content is served from cache. In current case it shows that cache is filled optimally and we can do even better if we tune caches more. The site contains also pages that are discarded when some subsite changes (page was added/modified/deleted) and one modification may affect about four or five pages. This may also decrease cache hit count because during day the site gets about 5-10 new pages. Cache hit ratio is currently extremely good. The suggested minimum is about 85% but after some tuning and measuring I achieved 98.7% as a result. This is due to the fact that new pages are most often requested and after new pages are added the older ones are requested only sometimes. So they get discarded from cache and only some of these will return sometimes back to cache. Although this may also indicate the need for additional SEO work the result is very well in technical means. Conclusion Measuring ASP.NET output cache is not complex thing to do and you can start by measuring performance of cache as a start. Later you can move on and measure caching effect to other counters such as disk I/O, network, processors etc. What you have to achieve is optimal cache that is not full of items asked only couple of times per day (you can avoid this by not using too long cache durations). After some tuning you should be able to boost cache hit ratio up to at least 85%.

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• Lies, damned lies, and statistics Part 2

  - by Maria Colgan

  There was huge interest in our OOW session last year on Managing Optimizer Statistics. It seems statistics and the maintenance of them continues to baffle people. In order to help dispel the mysteries surround statistics management we have created a two part white paper series on Optimizer statistics.  Part one of this series was released in November last years and describes in detail, with worked examples, the different concepts of Optimizer statistics. Today we have published part two of the series, which focuses on the best practices for gathering statistics, and examines specific use cases including, the fears that surround histograms and statistics management of volatile tables like Global Temporary Tables. Here is a quick look at the Introduction and the start of the paper. You can find the full paper here. Happy Reading! Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman","serif";} Introduction The Oracle Optimizer examines all of the possible plans for a SQL statement and picks the one with the lowest cost, where cost represents the estimated resource usage for a given plan. In order for the Optimizer to accurately determine the cost for an execution plan it must have information about all of the objects (table and indexes) accessed in the SQL statement as well as information about the system on which the SQL statement will be run. This necessary information is commonly referred to as Optimizer statistics. Understanding and managing Optimizer statistics is key to optimal SQL execution. Knowing when and how to gather statistics in a timely manner is critical to maintaining acceptable performance. This whitepaper is the second of a two part series on Optimizer statistics. The first part of this series, Understanding Optimizer Statistics, focuses on the concepts of statistics and will be referenced several times in this paper as a source of additional information. This paper will discuss in detail, when and how to gather statistics for the most common scenarios seen in an Oracle Database. The topics are · How to gather statistics · When to gather statistics · Improving the efficiency of gathering statistics · When not to gather statistics · Gathering other types of statistics How to gather statistics The preferred method for gathering statistics in Oracle is to use the supplied automatic statistics-gathering job. Automatic statistics gathering job The job collects statistics for all database objects, which are missing statistics or have stale statistics by running an Oracle AutoTask task during a predefined maintenance window. Oracle internally prioritizes the database objects that require statistics, so that those objects, which most need updated statistics, are processed first. The automatic statistics-gathering job uses the DBMS_STATS.GATHER_DATABASE_STATS_JOB_PROC procedure, which uses the same default parameter values as the other DBMS_STATS.GATHER_*_STATS procedures. The defaults are sufficient in most cases. However, it is occasionally necessary to change the default value of one of the statistics gathering parameters, which can be accomplished by using the DBMS_STATS.SET_*_PREF procedures. Parameter values should be changed at the smallest scope possible, ideally on a per-object bases. You can find the full paper here. Happy Reading! +Maria Colgan

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• Silverlight Cream for February 21, 2011 -- #1049

  - by Dave Campbell

  In this Issue: Rob Eisenberg(-2-), Gill Cleeren, Colin Eberhardt, Alex van Beek, Ishai Hachlili, Ollie Riches, Kevin Dockx, WindowsPhoneGeek(-2-), Jesse Liberty(-2-), and John Papa. Above the Fold: Silverlight: "Silverlight 4: Creating useful base classes for your views and viewmodels with PRISM 4" Alex van Beek WP7: "Google Sky on Windows Phone 7" Colin Eberhardt Shoutouts: My friends at SilverlightShow have their top 5 for last week posted: SilverlightShow for Feb 14 - 20, 2011 From SilverlightCream.com: Rob Eisenberg MVVMs Us with Caliburn.Micro! Rob Eisenberg chats with Carl and Richard on .NET Rocks episode 638 about Caliburn.Micro which takes Convention-over-Configuration further, utilizing naming conventions to handle a large number of data binding, validation and other action-based characteristics in your app. Two Caliburn Releases in One Day! Rob Eisenberg also announced that release candidates for both Caliburn 2.0 and Caliburn.Micro 1.0 are now available. Check out the docs and get the bits. Getting ready for Microsoft Silverlight Exam 70-506 (Part 6) Gill Cleeren has Part 6 of his series on getting ready for the Silverlight Exam up at SilverlightShow.... this time out, Gill is discussing app startup, localization, and using resource dictionaries, just to name a few things. Google Sky on Windows Phone 7 Colin Eberhardt has a very cool WP7 app described where he's using Google Sky as the tile source for Bing Maps, and then has a list of 110 Messier Objects.. interesting astronomical objects that you can look at... all with source! Silverlight 4: Creating useful base classes for your views and viewmodels with PRISM 4 Alex van Beek has some Prism4/Unity MVVM goodness up with this discussion of a login module using View and ViewModel base classes. Windows Phone 7 and WCF REST – Authentication Solutions Ishai Hachlili sent me this link to his post about WCF REST web service and authentication for WP7, and he offers up 2 solutions... from the looks of this, I'm also putting his blog on my watch list WP7Contrib: Isolated Storage Cache Provider Ollie Riches has a complete explanation and code example of using the IsolatedStorageCacheProvider in their WP7Contrib library. Using a ChannelFactory in Silverlight, part two: binary cows & new-born calves Kevin Dockx follows-up his post on Channel Factories with this part 2, expanding the knowledge-base into usin parameters and custom binding with binary encoding, both from reader suggestions. All about UriMapping in WP7 WindowsPhoneGeek has a post up about URI mappings in WP7 ... what it is, how to enable it in code behind or XAML, then using it either with a hyperlink button or via the NavigationService class... all with code. Passing WP7 Memory Consumption requirements with the Coding4Fun MemoryCounter tool WindowsPhoneGeek's latest is a tutorial on the use of the Memory Counter control from the Coding4Fun toolkit and WP7 Memory consumption. Getting Started With Linq Jesse Liberty gets into LINQ in his Episode 33 of his WP7 'From Scratch' series... looks like a good LINQ starting point, and he's going to be doing a series on it. Linq with Objects In his second post on LINQ, Jesse Liberty is looking at creating a Linq query against a collection of objects... always good stuff, Jesse! Silverlight TV Silverlight TV 62: The Silverlight 5 Triad Unplugged John Papa is joined by Sam George, Larry Olson, and Vijay Devetha (the Silverlight Triad) on this Silverlight TV episode 62 to discuss how the team works together, and hey... they're hiring! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Folders in SQL Server Data Tools

  - by jamiet

  Recently I have begun a new project in which I am using SQL Server Data Tools (SSDT) and SQL Server Integration Services (SSIS) 2012. Although I have been using SSDT & SSIS fairly extensively while SQL Server 2012 was in the beta phase I usually find that you don’t learn about the capabilities and quirks of new products until you use them on a real project, hence I am hoping I’m going to have a lot of experiences to share on my blog over the coming few weeks. In this first such blog post I want to talk about file and folder organisation in SSDT. The predecessor to SSDT is Visual Studio Database Projects. When one created a new Visual Studio Database Project a folder structure was provided with “Schema Objects” and “Scripts” in the root and a series of subfolders for each schema: Apparently a few customers were not too happy with the tool arbitrarily creating lots of folders in Solution Explorer and hence SSDT has gone in completely the opposite direction; now no folders are created and new objects will get created in the root – it is at your discretion where they get moved to: After using SSDT for a few weeks I can safely say that I preferred the older way because I never used Solution Explorer to navigate my schema objects anyway so it didn’t bother me how many folders it created. Having said that the thought of a single long list of files in Solution Explorer without any folders makes me shudder so on this project I have been manually creating folders in which to organise files and I have tried to mimic the old way as much as possible by creating two folders in the root, one for all schema objects and another for Pre/Post deployment scripts: This works fine until different developers start to build their own different subfolder structures; if you are OCD-inclined like me this is going to grate on you eventually and hence you are going to want to move stuff around so that you have consistent folder structures for each schema and (if you have multiple databases) each project. Moreover new files get created with a filename of the object name + “.sql” and often people like to have an extra identifier in the filename to indicate the object type: The overall point is this – files and folders in your solution are going to change. Some version control systems (VCSs) don’t take kindly to files being moved around or renamed because they recognise the renamed/moved file simply as a new file and when they do that you lose the revision history which, to my mind, is one of the key benefits of using a VCS in the first place. On this project we have been using Team Foundation Server (TFS) and while it pains me to say it (as I am no great fan of TFS’s version control system) it has proved invaluable when dealing with the SSDT problems that I outlined above because it is integrated right into the Visual Studio IDE. Thus the advice from this blog post is: If you are using SSDT consider using an Visual-Studio-integrated VCS that can easily handle file renames and file moves I suspect that fans of other VCSs will counter by saying that their VCS weapon of choice can handle renames/file moves quite satisfactorily and if that’s the case…great…let me know about them in the comments. This blog post is not an attempt to make people use one particular VCS, only to make people aware of this issue that might rise when using SSDT. More to come in the coming few weeks! @jamiet

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• Using the Script Component as a Conditional Split

  This is a quick walk through on how you can use the Script Component to perform Conditional Split like behaviour, splitting your data across multiple outputs. We will use C# code to decide what does flows to which output, rather than the expression syntax of the Conditional Split transformation. Start by setting up the source. For my example the source is a list of SQL objects from sys.objects, just a quick way to get some data: SELECT type, name FROM sys.objects type name S syssoftobjrefs F FK_Message_Page U Conference IT queue_messages_23007163 Shown above is a small sample of the data you could expect to see. Once you have setup your source, add the Script Component, selecting Transformation when prompted for the type, and connect it up to the source. Now open the component, but don’t dive into the script just yet. First we need to select some columns. Select the Input Columns page and then select the columns we want to uses as part of our filter logic. You don’t need to choose columns that you may want later, this is just the columns used in the script itself. Next we need to add our outputs. Select the Inputs and Outputs page.You get one by default, but we need to add some more, it wouldn’t be much of a split otherwise. For this example we’ll add just one more. Click the Add Output button, and you’ll see a new output is added. Now we need to set some properties, so make sure our new Output 1 is selected. In the properties grid change the SynchronousInputID property to be our input Input 0, and  change the ExclusionGroup property to 1. Now select Ouput 0 and change the ExclusionGroup property to 2. This value itself isn’t important, provided each output has a different value other than zero. By setting this property on both outputs it allows us to split the data down one or the other, making each exclusive. If we left it to 0, that output would get all the rows. It can be a useful feature allowing you to copy selected rows to one output whilst retraining the full set of data in the other. Now we can go back to the Script page and start writing some code. For the example we will do a very simple test, if the value of the type column is U, for user table, then it goes down the first output, otherwise it ends up in the other. This mimics the exclusive behaviour of the conditional split transformation. public override void Input0_ProcessInputRow(Input0Buffer Row) { // Filter all user tables to the first output, // the remaining objects down the other if (Row.type.Trim() == "U") { Row.DirectRowToOutput0(); } else { Row.DirectRowToOutput1(); } } The code itself is very simple, a basic if clause that determines which of the DirectRowToOutput methods we call, there is one for each output. Of course you could write a lot more code to implement some very complex logic, but the final direction is still just a method call. If we now close the script component, we can hook up the outputs and test the package. Your numbers will vary depending on the sample database but as you can see we have clearly split out input data into two outputs. As a final tip, when adding the outputs I would normally rename them, changing the Name in the Properties grid. This means the generated methods follow the pattern as do the path label shown on the design surface, making everything that much easier to recognise.

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• Requesting feedback on my OO design

  - by Prog

  I'm working on an application that creates music by itself. I'm seeking feedback for my OO design so far. This question will focus on one part of the program. The application produces Tune objects, that are the final musical products. Tune is an abstract class with an abstract method play. It has two subclasses: SimpleTune and StructuredTune. SimpleTune owns a Melody and a Progression (chord sequence). It's play implementation plays these two objects simultaneously. StructuredTune owns two Tune instances. It's own play plays the two Tunes one after the other according to a pattern (currently only ABAB). Melody is an abstract class with an abstract play method. It has two subclasses: SimpleMelody and StructuredMelody. SimpleMelody is composed of an array of notes. Invoking play on it plays these notes one after the other. StructuredMelody is composed of an array of Melody objects. Invoking play on it plays these Melodyies one after the other. I think you're starting to see the pattern. Progression is also an abstract class with a play method and two subclasses: SimpleProgression and StructuredProgression, each composed differently and played differently. SimpleProgression owns an array of chords and plays them sequentially. StructuredProgression owns an array of Progressions and it's play implementation plays them sequentially. Every class has a corresponding Generator class. Tune, Melody and Progression are matched with corresponding abstract TuneGenerator, MelodyGenerator and ProgressionGenerator classes, each with an abstract generate method. For example MelodyGenerator defines an abstract Melody generate method. Each of the generators has two subclasses, Simple and Structured. So for example MelodyGenerator has a subclasses SimpleMelodyGenerator, with an implementation of generate that returns a SimpleMelody. (It's important to note that the generate methods encapsulate complex algorithms. They are more than mere factory method. For example SimpleProgressionGenerator.generate() implements an algorithm to compose a series of Chord objects, which are used to instantiate the returned SimpleProgression). Every Structured generator uses another generator internally. It is a Simple generator be default, but in special cases may be a Structured generator. Parts of this design are meant to allow the end-user through the GUI to choose what kind of music is to be created. For example the user can choose between a "simple tune" (SimpleTuneGenerator) and a "full tune" (StructuredTuneGenerator). Other parts of the system aren't subject to direct user-control. What do you think of this design from an OOD perspective? What potential problems do you see with this design? Please share with me your criticism, I'm here to learn. Apart from this, a more specific question: the "every class has a corresponding Generator class" part feels very wrong. However I'm not sure how I could design this differently and achieve the same flexibility. Any ideas?

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• SQL SERVER – Solution – User Not Able to See Any User Created Object in Tables – Security and Permissions Issue

  - by pinaldave

  There is an old quote “A Picture is Worth a Thousand Words”. I believe this quote immensely. Quite often I get phone calls that something is not working if I can help. My reaction is in most of the cases, I need to know more, send me exact error or a screenshot. Until and unless I see the error or reproduce the scenario myself I prefer not to comment. Yesterday I got a similar phone call from an old friend, where he was not sure what is going on. Here is what he said. “When I try to connect to SQL Server, it lets me connect just fine as well let me open and explore the database. I noticed that I do not see any user created instances but when my colleague attempts to connect to the server, he is able to explore the database as well see all the user created tables and other objects. Can you help me fix it? “ My immediate reaction was he was facing security and permission issue. However, to make the same recommendation I suggested that he send me a screenshot of his own SSMS and his friend’s SSMS. After carefully looking at both the screenshots, I was very confident about the issue and we were able to resolve the issue. Let us reproduce the same scenario and many there is some learning for us. Issue: User not able to see user created objects First let us see the image of my friend’s SSMS screen. (Recreated on my machine) Now let us see my friend’s colleague SSMS screen. (Recreated on my machine) You can see that my friend could not see the user tables but his colleague was able to do the same for sure. Now I believed it was a permissions issue. Further to this I asked him to send me another image where I can see the various permissions of the user in the database. My friends screen My friends colleagues screen This indeed proved that my friend did not have access to the AdventureWorks database and because of the same he was not able to access the database. He did have public access which means he will have similar rights as guest access. However, their SQL Server had followed my earlier advise on having limited access for guest access, which means he was not able to see any user created objects. My next question was to validate what kind of access my friend’s colleague had. He replied that the colleague is the admin of the server. I suggested that if my friend was suppose to have admin access to the database, he should request of having admin access to his colleague. My friend promptly asked for the same to his colleague and on following screen he added him as an admin. You can do the same using following T-SQL script as well. USE [AdventureWorks2012] GO ALTER ROLE [db_owner] ADD MEMBER [testguest] GO Once my friend was admin he was able to access all the user objects just like he was expecting. Please note, this complete exercise was done on a development server. One should not play around with security on live or production server. Security is such an issue, which should be left with only senior administrator of the server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• How Do You Actually Model Data?

  Since the 1970’s Developers, Analysts and DBAs have been able to represent concepts and relations in the form of data through the use of generic symbols.  But what is data modeling?  The first time I actually heard this term I could not understand why anyone would want to display a computer on a fashion show runway. Hey, what do you expect? At that time I was a freshman in community college, and obviously this was a long time ago.  I have since had the chance to learn what data modeling truly is through using it. Data modeling is a process of breaking down information and/or requirements in to common categories called objects. Once objects start being defined then relationships start to form based on dependencies found amongst other existing objects.  Currently, there are several tools on the market that help data designer actually map out objects and their relationships through the use of symbols and lines.  These diagrams allow for designs to be review from several perspectives so that designers can ensure that they have the optimal data design for their project and that the design is flexible enough to allow for potential changes and/or extension in the future. Additionally these basic models can always be further refined to show different levels of details depending on the target audience through the use of three different types of models. Conceptual Data Model(CDM)Conceptual Data Models include all key entities and relationships giving a viewer a high level understanding of attributes. Conceptual data model are created by gathering and analyzing information from various sources pertaining to a project during the typical planning phase of a project. Logical Data Model (LDM)Logical Data Models are conceptual data models that have been expanded to include implementation details pertaining to the data that it will store. Additionally, this model typically represents an origination’s business requirements and business rules by defining various attribute data types and relationships regarding each entity. This additional information can be directly translated to the Physical Data Model which reduces the actual time need to implement it. Physical Data Model(PDMs)Physical Data Model are transformed Logical Data Models that include the necessary tables, columns, relationships, database properties for the creation of a database. This model also allows for considerations regarding performance, indexing and denormalization that are applied through database rules, data integrity. Further expanding on why we actually use models in modern application/database development can be seen in the benefits that data modeling provides for data modelers and projects themselves, Benefits of Data Modeling according to Applied Information Science Abstraction that allows data designers remove concepts and ideas form hard facts in the form of data. This gives the data designers the ability to express general concepts and/or ideas in a generic form through the use of symbols to represent data items and the relationships between the items. Transparency through the use of data models allows complex ideas to be translated in to simple symbols so that the concept can be understood by all viewpoints and limits the amount of confusion and misunderstanding. Effectiveness in regards to tuning a model for acceptable performance while maintaining affordable operational costs. In addition it allows systems to be built on a solid foundation in terms of data. I shudder at the thought of a world without data modeling, think about it? Data is everywhere in our lives. Data modeling allows for optimizing a design for performance and the reduction of duplication. If one was to design a database without data modeling then I would think that the first things to get impacted would be database performance due to poorly designed database and there would be greater chances of unnecessary data duplication that would also play in to the excessive query times because unneeded records would need to be processed. You could say that a data designer designing a database is like a box of chocolates. You will never know what kind of database you will get until after it is built.

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• Utility to Script SQL Server Configuration

  - by Bill Graziano

  I wrote a small utility to script some key SQL Server configuration information. I had two goals for this utility: Assist with disaster recovery preparation Identify configuration changes I’ve released the application as open source through CodePlex. You can download it from CodePlex at the Script SQL Server Configuration project page. The application is a .NET 2.0 console application that uses SMO. It writes its output to a directory that you specify.  Disaster Planning ScriptSqlConfig generates scripts for logins, jobs and linked servers.  It writes the properties and configuration from the instance to text files. The scripts are designed so they can be run against a DR server in the case of a disaster. The properties and configuration will need to be manually compared. Each job is scripted to its own file. Each linked server is scripted to its own file. The linked servers don’t include the password if you use a SQL Server account to connect to the linked server. You’ll need to store those somewhere secure. All the logins are scripted to a single file. This file includes windows logins, SQL Server logins and any server role membership.  The SQL Server logins are scripted with the correct SID and hashed passwords. This means that when you create the login it will automatically match up to the users in the database and have the correct password. This is the only script that I programmatically generate rather than using SMO. The SQL Server configuration and properties are scripted to text files. These will need to be manually reviewed in the event of a disaster. Or you could DIFF them with the configuration on the new server. Configuration Changes These scripts and files are all designed to be checked into a version control system.  The scripts themselves don’t include any date specific information. In my environments I run this every night and check in the changes. I call the application once for each server and script each server to its own directory.  The process will delete any existing files before writing new ones. This solved the problem I had where the scripts for deleted jobs and linked servers would continue to show up.  To see any changes I just need to query the version control system to show many any changes to the files. Database Scripting Utilities that script database objects are plentiful.  CodePlex has at least a dozen of them including one I wrote years ago. The code is so easy to write it’s hard not to include that functionality. This functionality wasn’t high on my list because it’s included in a database backup.  Unless you specify the /nodb option, the utility will script out many user database objects. It will script one object per file. It will script tables, stored procedures, user-defined data types, views, triggers, table types and user-defined functions. I know there are more I need to add but haven’t gotten around it yet. If there’s something you need, please log an issue and get it added. Since it scripts one object per file these really aren’t appropriate to recreate an empty database. They are really good for checking into source control every night and then seeing what changed. I know everyone tells me all their database objects are in source control but a little extra insurance never hurts. Conclusion I hope this utility will help a few of you out there. My goal is to have it script all server objects that aren’t contained in user databases. This should help with configuration changes and especially disaster recovery.

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