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  • Internal classes with ADO.NET Entity Framework

    - by Regent
    I'm using Entity Framework for creation of my Data Access Layer and I want for all of my classes to be internal. I know it is possible to manually assign it manually in the designer for each class. But looks like it also requires to set internal modifier for each single property in every class! I have about 30+ entities and it will be a huge work to do. Do you know any ideas how to set a 'default access' for the entire model?

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  • How to implement table-per-concrete-type using entity framework

    - by SDReyes
    Hello Guys! I'm mapping a set of tables that share a common set of fields: So as you can see I'm using a table-per-concrete-type strategy to map the inheritance. But... I have not could to relate them to an abstract type containing these common properties. It's possible to do it using EF? BONUS: The only non documented Entity Data Model Mapping Scenario is Table-per-concrete-type inheritance http://msdn.microsoft.com/en-us/library/cc716779.aspx : P

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  • Entity Framework 4 and Public Properties

    - by William
    I am working on a project and I am using Entity Framework 4 as my ORM. I am implementing POCO classes. Every example I see with EF 4 and POCOs implements all properties with public setters. Is that the only way I can use POCO classes with EF 4? Do all my setters need to be public?

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  • Using Joins vs Entity associations

    - by shivesh
    I am learning Entity framework and linq-to-entities. It's possible to get cross values from multiple tables using JOINS (join keyword) or using the navigation fields ( associations) in which case the framework knows how to reference the cross data. My question is what to use when?

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  • How to get address the object of an related entity with CoreData ?

    - by eemceebee
    Hi Ok, after I ran into a dead end modifieing an existing Apple example for CoreData, I started completely new creating my own project and that worked fine,..... until I tried to access a related entity. So here is what I did. I created 2 entities, where one is just the detail information of the other one, so there is a one-2-one relationship. Entity #1, Stocks: name value details -- relationship to Entity #2 Entity #2, StockDetails: bank published stock -- relationship to Entity #1 Now, I created the "Managed Object Class" for both of the Entities. Then I created a few lines to put some data into it NSManagedObjectContext *context = [self managedObjectContext]; Stocks *stockinfo= [NSEntityDescription insertNewObjectForEntityForName:@"Stocks" inManagedObjectContext:context]; stockinfo.name = @"Apple"; stockinfo.value = [NSNumber numberWithInt:200]; StockDetails *thestockdetails = [NSEntityDescription insertNewObjectForEntityForName:@"StockDetails" inManagedObjectContext:context]; thestockdetails.bank = @"Bank of America"; thestockdetails.published = [NSDate date]; thestockdetails.stock = stocks_; stockinfo.details = thestockdetails ; NSError *error; if (![context save:&error]) { NSLog(@"A Problem occured, couldn't save: %@", [error localizedDescription]); } Just want to mention here, that I do not get an error with this. Next I put everything into a UITableViewController for a preview and another for a detail view. The preview just shows infos form Entity #1 (Stocks) and when selected it shows the detail view. Now here I also display the infos form Entity #1 (Stocks) but I want to show the Entity #2 (StockDetails) aswell. This is how I try to access the data : StockDetails *details_ = [stockinfo details]; And this gives me a EXC_BAD_ACCESS. So any idea what I am doing wrong here ? Thanks

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  • Facial Recognition for Retail

    - by David Dorf
    My son decided to do his science project on how the brain recognizes faces.  Faces are so complicated and important that the brain has a dedicated area for just that purpose.  During our research, we came across some emerging uses for facial recognition in the retail industry. If you believe the movies, recognizing faces as they walk by a camera is easy for computers but that's not the reality.  Huge investments are being made by the U.S. government in this area, with a focus on airport security.  Now, companies like Eye See are leveraging that research for marketing purposes.  They do things like track eyes while viewing newspaper ads to see which ads get more "eye time."  This can help marketers make better placement and color decisions. But what caught my eye (that was too easy) was their new mannequins that watch shoppers.  These mannequins, being tested at European retailers like Benetton, watch shoppers that walk by and identify their gender, race, and age.  This helps the retailer better understand the types of customers being attracted to the outfit on the mannequin.  Of course to be most accurate, the software has pictures of the employees so they can be filtered out.  Since the mannequins are closer to the shoppers and at eye-level, they are more accurate than traditional in-ceiling LP cameras. Marketing agency RedPepper is offering retailers the ability to recognize loyalty shoppers at their doors using Facedeal.  For customers that have opted into the program, when they enter the store their face is recognized and they are checked in.  Then, as a reward, they are sent an offer on their smartphone. It won't be long before retailers begin to listen to shoppers are they walk the aisles, then keywords can be collected and aggregated to give the retailer an idea of what people are saying about their stores and products.  Sentiment analysis based on what's said or even facial expressions can't be far off. Clearly retailers need to be cautions and respect customer privacy.  That's why these technologies are emerging slowly.  But since the next generation of shoppers are less concerned about privacy, I expect these technologies to appear sporadically in the next five years then go mainstream.  Time will tell.

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  • how to define service runlevel order position?

    - by DmitrySemenov
    I setup bind-dlz and need mysql start prior NAMED when system starts here is what I have [root@semenov]# ./test.sh mysql 0:off 1:off 2:on 3:on 4:on 5:on 6:off named 0:off 1:off 2:off 3:on 4:on 5:on 6:off lrwxrwxrwx. 1 root root 15 Apr 15 18:57 /etc/rc3.d/S93mysql -> ../init.d/mysql lrwxrwxrwx. 1 root root 15 Apr 15 18:57 /etc/rc3.d/S90named -> ../init.d/named here is what I have in mysql init script # Comments to support chkconfig on RedHat Linux # chkconfig: 2345 84 16 # description: A very fast and reliable SQL database engine. # Comments to support LSB init script conventions ### BEGIN INIT INFO # Provides: mysql # Required-Start: $local_fs $network $remote_fs # Should-Start: ypbind nscd ldap ntpd xntpd # Required-Stop: $local_fs $network $remote_fs # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: start and stop MySQL # Description: MySQL is a very fast and reliable SQL database engine. ### END INIT INFO so when I remove named from chkconfig and have there just mysql, it starts with order number 84: /etc/rc3.d/S84mysql - ../init.d/mysql but when I add named inside chkconfig it's order changes to 93: /etc/rc3.d/S93mysql - ../init.d/mysql as a result mysql will be starting after named and named will fail (no sql available) any ideas what I'm doing wrong? here is what I have in named init script # chkconfig: 345 90 16 # description: named (BIND) is a Domain Name Server (DNS) \ # that is used to resolve host names to IP addresses. # probe: true ### BEGIN INIT INFO # Provides: $named # Required-Start: $local_fs $network $syslog # Required-Stop: $local_fs $network $syslog # Default-Start:2 3 4 # Default-Stop: 0 1 2 3 4 5 6 # Short-Description: start|stop|status|restart|try-restart|reload|force-reload DNS server # Description: control ISC BIND implementation of DNS server ### END INIT INFO thanks, Dmitry

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  • Entity Framework and multi-tenancy database design

    - by Junto
    I am looking at multi-tenancy database schema design for an SaaS concept. It will be ASP.NET MVC - EF, but that isn't so important. Below you can see an example database schema (the Tenant being the Company). The CompanyId is replicated throughout the schema and the primary key has been placed on both the natural key, plus the tenant Id. Plugging this schema into the Entity Framework gives the following errors when I add the tables into the Entity Model file (Model1.edmx): The relationship 'FK_Order_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderId, CompanyId}' of the table 'Order'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Order' uses the set of foreign keys '{OrderId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_Order_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderId, CompanyId}' of the table 'Order'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Order' uses the set of foreign keys '{OrderId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Product' uses the set of foreign keys '{ProductId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The question is in two parts: Is my database design incorrect? Should I refrain from these compound primary keys? I'm questioning my sanity regarding the fundamental schema design (frazzled brain syndrome). Please feel free to suggest the 'idealized' schema. Alternatively, if the database design is correct, then is EF unable to match the keys because it perceives these foreign keys as a potential mis-configured 1:1 relationships (incorrectly)? In which case, is this an EF bug and how can I work around it?

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  • Execute a SQlite command with Entity Framework

    - by Filimindji
    Hi everybody, I use a SQLite database and Entity Framework (with .net framework 3.5). I'm trying to execute a simple SQL non query command to create a new table in this datase. My Entity Framework already contains the object model for this table : I just want to generate the corresponding table using a command. (By the way, there is maybe a better way to do this. Any ideas someone :) My problem is that I'm not able to execute any command, even the simple commands. Here is my code : EntityConnection entityConnection = new EntityConnection(entitiesConnectionString); Entities db = new Entities(entityConnection); DbCommand command = db.Connection.CreateCommand(); command.CommandText ="CREATE TABLE MyTable (Id int NOT NULL, OtherTable_Id nchar(40) REFERENCES OtherTable (Id) On Delete CASCADE On Update NO ACTION, SomeData nvarchar(1024) NOT NULL, Primary Key(Id) );"; command.ExecuteNonQuery(); I got this error : System.Data.EntitySqlException: The query syntax is not valid., near identifier 'TABLE', line 1, column 8. at System.Data.Common.EntitySql.CqlParser.yyerror(String s) at System.Data.Common.EntitySql.CqlParser.yyparse() at System.Data.Common.EntitySql.CqlParser.Parse(String query) at System.Data.Common.EntitySql.CqlQuery.Parse(String query, ParserOptions parserOptions) at System.Data.Common.EntitySql.CqlQuery.Compile(String query, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables, Boolean validateTree) at System.Data.EntityClient.EntityCommand.MakeCommandTree() at System.Data.EntityClient.EntityCommand.CreateCommandDefinition() at System.Data.EntityClient.EntityCommand.TryGetEntityCommandDefinitionFromQueryCache(EntityCommandDefinition& entityCommandDefinition) at System.Data.EntityClient.EntityCommand.GetCommandDefinition() at System.Data.EntityClient.EntityCommand.InnerPrepare() at System.Data.EntityClient.EntityCommand.ExecuteReader(CommandBehavior behavior) at System.Data.EntityClient.EntityCommand.ExecuteScalar[T_Result](Func`2 resultSelector) It's seem to be a syntax error, but I can't figure where is the problem and how to resolve it. The entityConnection is ok because I can use any entities generated with EF. I tried with another simple command, but it throw another exception : DbCommand command = db.Connection.CreateCommand(); command.CommandText = "SELECT COUNT(Id) From OtherTable;"; int result = (int)command.ExecuteScalar(); And I got this error, witch is not the same, but may help : System.Data.EntitySqlException: 'Groupe' could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly., near simple identifier, line 1, column 23. at System.Data.Common.EntitySql.CqlErrorHelper.ReportIdentifierError(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertIdentifier(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.Convert(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessAliasedFromClauseItem(AliasExpr aliasedExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessFromClauseItem(FromClauseItem fromClauseItem, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessFromClause(FromClause fromClause, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertQuery(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.Convert(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertRootExpression(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertGeneralExpression(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.CqlQuery.AnalyzeSemantics(Expr astExpr, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables) at System.Data.Common.EntitySql.CqlQuery.Compile(String query, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables, Boolean validateTree) at System.Data.EntityClient.EntityCommand.MakeCommandTree() at System.Data.EntityClient.EntityCommand.CreateCommandDefinition() at System.Data.EntityClient.EntityCommand.TryGetEntityCommandDefinitionFromQueryCache(EntityCommandDefinition& entityCommandDefinition) at System.Data.EntityClient.EntityCommand.GetCommandDefinition() at System.Data.EntityClient.EntityCommand.InnerPrepare() at System.Data.EntityClient.EntityCommand.ExecuteReader(CommandBehavior behavior) at System.Data.EntityClient.EntityCommand.ExecuteScalar[T_Result](Func`2 resultSelector)

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  • Problem creating ObjectContext from different project inside solution.

    - by Levelbit
    I have two projects in my Solution. One implements my business logic and has defined entity model of entity framework. When I want to work with classes defined within this project from another project I have some problems in runtime. Actually, the most concerning thing is why I can not instantiate my, so called, TicketEntities(ObjectContext) object from other projects? when I catch following exception: The specified named connection is either not found in the configuration, not intended to be used with the EntityClient provider, or not valid. I found out it's brake at: public partial class TicketEntities : global::System.Data.Objects.ObjectContext { public TicketEntities() : base("name=TicketEntities", "TicketEntities") { this.OnContextCreated(); } with exception: Unable to load the specified metadata resource. Just to remind you everthing works fine from orginal project.

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  • Opening an SQL CE file at runtime with Entity Framework 4

    - by David Veeneman
    I am getting started with Entity Framework 4, and I an creating a demo app as a learning exercise. The app is a simple documentation builder, and it uses a SQL CE store. Each documentation project has its own SQL CE data file, and the user opens one of these files to work on a project. The EDM is very simple. A documentation project is comprised of a list of subjects, each of which has a title, a description, and zero or more notes. So, my entities are Subject, which contains Title and Text properties, and Note, which has Title and Text properties. There is a one-to-many association from Subject to Note. I am trying to figure out how to open an SQL CE data file. A data file must match the schema of the SQL CE database created by EF4's Create Database Wizard, and I will implement a New File use case elsewhere in the app to implement that requirement. Right now, I am just trying to get an existing data file open in the app. I have reproduced my existing 'Open File' code below. I have set it up as a static service class called File Services. The code isn't working quite yet, but there is enough to show what I am trying to do. I am trying to hold the ObjectContext open for entity object updates, disposing it when the file is closed. So, here is my question: Am I on the right track? What do I need to change to make this code work with EF4? Is there an example of how to do this properly? Thanks for your help. My existing code: public static class FileServices { #region Private Fields // Member variables private static EntityConnection m_EntityConnection; private static ObjectContext m_ObjectContext; #endregion #region Service Methods /// <summary> /// Opens an SQL CE database file. /// </summary> /// <param name="filePath">The path to the SQL CE file to open.</param> /// <param name="viewModel">The main window view model.</param> public static void OpenSqlCeFile(string filePath, MainWindowViewModel viewModel) { // Configure an SQL CE connection string var sqlCeConnectionString = string.Format("Data Source={0}", filePath); // Configure an EDM connection string var builder = new EntityConnectionStringBuilder(); builder.Metadata = "res://*/EF4Model.csdl|res://*/EF4Model.ssdl|res://*/EF4Model.msl"; builder.Provider = "System.Data.SqlServerCe"; builder.ProviderConnectionString = sqlCeConnectionString; var entityConnectionString = builder.ToString(); // Connect to the model m_EntityConnection = new EntityConnection(entityConnectionString); m_EntityConnection.Open(); // Create an object context m_ObjectContext = new Model1Container(); // Get all Subject data IQueryable<Subject> subjects = from s in Subjects orderby s.Title select s; // Set view model data property viewModel.Subjects = new ObservableCollection<Subject>(subjects); } /// <summary> /// Closes an SQL CE database file. /// </summary> public static void CloseSqlCeFile() { m_EntityConnection.Close(); m_ObjectContext.Dispose(); } #endregion }

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  • 'Generic' ViewModel

    - by Ian MacPherson
    Using EF 4, I have several subtypes of a 'Business' entity (customers, suppliers, haulage companies etc). They DO need to be subtypes. I am building a general viewmodel which calls into a service from which a generic repository is accessed. As I have 4 subtypes, it would be good to have a 'generic' viewmodel used for all of these. Problem is of course is that I have to call a specific type into my generic repository, for example: BusinessToRetrieve = _repository .LoadEntity<Customer>(o => o.CustomerID == customerID); It would be good to be able to call <SomethingElse>, somethingElse being one or other of the subtypes), otherwise I shall have to create 4 near identical viemodels, which seems a waste of course! The subtype entity name is available to the viewmodel but I've been unable to figure out how to make the above call convert this into a type. An issue with achieving what I want is that presumably the lambda expression being passed in wouldn't be able to resolve on a 'generic' call ?

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  • ASP.net MVC 2.0 using the same form for adding and editing.

    - by Chevex
    I would like to use the same view for editing a blog post and adding a blog post. However, I'm having an issue with the ID. When adding a blog post, I have no need for an ID value to be posted. When model binding binds the form values to the BlogPost object in the controller, it will auto-generate the ID in entity framework entity. When I am editing a blog post I DO need a hidden form field to store the ID in so that it accompanies the next form post. Here is the view I have right now. <% using (Html.BeginForm("CommitEditBlogPost", "Admin")) { %> <% if (Model != null) { %> <%: Html.HiddenFor(x => x.Id)%> <% } %> Title:<br /> <%: Html.TextBoxFor(x => x.Title, new { Style = "Width: 90%;" })%> <br /> <br /> Summary:<br /> <%: Html.TextAreaFor(x => x.Summary, new { Style = "Width: 90%; Height: 50px;" }) %> <br /> <br /> Body:<br /> <%: Html.TextAreaFor(x => x.Body, new { Style = "Height: 250px; Width: 90%;" })%> <br /> <br /> <input type="submit" value="Submit" /> <% } %> Right now checking if the model is coming in NULL is a great way to know if I'm editing a blog post or adding one, because when I'm adding one it will be null as it hasn't been created yet. The problem comes in when there is an error and the entity is invalid. When the controller renders the form after an invalid model the Model != null evaluates to false, even though we are editing a post and there is clearly a model. If I render the hidden input field for ID when adding a post, I get an error stating that the ID can't be null. Any help is appreciated. EDIT: I went with OJ's answer for this question, however I discovered something that made me feel silly and I wanted to share it just in case anyone was having a similar issue. The page the adds/edits blogs does not even need a hidden field for id, ever. The reason is because when I go to add a blog I do a GET to this relative URL BlogProject/Admin/AddBlogPost This URL does not contain an ID and the action method just renders the page. The page does a POST to the same URL when adding the blog post. The incoming BlogPost entity has a null Id and is generated by EF during save changes. The same thing happens when I edit blog posts. The URL is BlogProject/Admin/EditBlogPost/{Id} This URL contains the id of the blog post and since the page is posting back to the exact same URL the id goes with the POST to the action method that executes the edit. The only problem I encountered with this is that the action methods cannot have identical signatures. [HttpGet] public ViewResult EditBlogPost(int Id) { } [HttpPost] public ViewResult EditBlogPost(int Id) { } The compiler will yell at you if you try to use these two methods above. It is far too convenient that the Id will be posted back when doing a Html.BeginForm() with no arguments for action or controller. So rather than change the name of the POST method I just modified the arguments to include a FormCollection. Like this: [HttpPost] public ViewResult EditBlogPost(int Id, FormCollection formCollection) { // You can then use formCollection as the IValueProvider for UpdateModel() // and TryUpdateModel() if you wish. I mean, you might as well use the // argument since you're taking it. } The formCollection variable is filled via model binding with the same content that Request.Form would be by default. You don't have to use this collection for UpdateModel() or TryUpdateModel() but I did just so I didn't feel like that collection was pointless since it really was just to make the method signature different from its GET counterpart. Thanks for the help guys!

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  • Caching NHibernate Named Queries

    - by TStewartDev
    I recently started a new job and one of my first tasks was to implement a "popular products" design. The parameters were that it be done with NHibernate and be cached for 24 hours at a time because the query will be pretty taxing and the results do not need to be constantly up to date. This ended up being tougher than it sounds. The database schema meant a minimum of four joins with filtering and ordering criteria. I decided to use a stored procedure rather than letting NHibernate create the SQL for me. Here is a summary of what I learned (even if I didn't ultimately use all of it): You can't, at the time of this writing, use Fluent NHibernate to configure SQL named queries or imports You can return persistent entities from a stored procedure and there are a couple ways to do that You can populate POCOs using the results of a stored procedure, but it isn't quite as obvious You can reuse your named query result mapping other places (avoid duplication) Caching your query results is not at all obvious Testing to see if your cache is working is a pain NHibernate does a lot of things right. Having unified, up-to-date, comprehensive, and easy-to-find documentation is not one of them. By the way, if you're new to this, I'll use the terms "named query" and "stored procedure" (from NHibernate's perspective) fairly interchangeably. Technically, a named query can execute any SQL, not just a stored procedure, and a stored procedure doesn't have to be executed from a named query, but for reusability, it seems to me like the best practice. If you're here, chances are good you're looking for answers to a similar problem. You don't want to read about the path, you just want the result. So, here's how to get this thing going. The Stored Procedure NHibernate has some guidelines when using stored procedures. For Microsoft SQL Server, you have to return a result set. The scalar value that the stored procedure returns is ignored as are any result sets after the first. Other than that, it's nothing special. CREATE PROCEDURE GetPopularProducts @StartDate DATETIME, @MaxResults INT AS BEGIN SELECT [ProductId], [ProductName], [ImageUrl] FROM SomeTableWithJoinsEtc END The Result Class - PopularProduct You have two options to transport your query results to your view (or wherever is the final destination): you can populate an existing mapped entity class in your model, or you can create a new entity class. If you go with the existing model, the advantage is that the query will act as a loader and you'll get full proxied access to the domain model. However, this can be a disadvantage if you require access to the related entities that aren't loaded by your results. For example, my PopularProduct has image references. Unless I tie them into the query (thus making it even more complicated and expensive to run), they'll have to be loaded on access, requiring more trips to the database. Since we're trying to avoid trips to the database by using a second-level cache, we should use the second option, which is to create a separate entity for results. This approach is (I believe) in the spirit of the Command-Query Separation principle, and it allows us to flatten our data and optimize our report-generation process from data source to view. public class PopularProduct { public virtual int ProductId { get; set; } public virtual string ProductName { get; set; } public virtual string ImageUrl { get; set; } } The NHibernate Mappings (hbm) Next up, we need to let NHibernate know about the query and where the results will go. Below is the markup for the PopularProduct class. Notice that I'm using the <resultset> element and that it has a name attribute. The name allows us to drop this into our query map and any others, giving us reusability. Also notice the <import> element which lets NHibernate know about our entity class. <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <import class="PopularProduct, Infrastructure.NHibernate, Version=1.0.0.0"/> <resultset name="PopularProductResultSet"> <return-scalar column="ProductId" type="System.Int32"/> <return-scalar column="ProductName" type="System.String"/> <return-scalar column="ImageUrl" type="System.String"/> </resultset> </hibernate-mapping>  And now the PopularProductsMap: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <sql-query name="GetPopularProducts" resultset-ref="PopularProductResultSet" cacheable="true" cache-mode="normal"> <query-param name="StartDate" type="System.DateTime" /> <query-param name="MaxResults" type="System.Int32" /> exec GetPopularProducts @StartDate = :StartDate, @MaxResults = :MaxResults </sql-query> </hibernate-mapping>  The two most important things to notice here are the resultset-ref attribute, which links in our resultset mapping, and the cacheable attribute. The Query Class – PopularProductsQuery So far, this has been fairly obvious if you're familiar with NHibernate. This next part, maybe not so much. You can implement your query however you want to; for me, I wanted a self-encapsulated Query class, so here's what it looks like: public class PopularProductsQuery : IPopularProductsQuery { private static readonly IResultTransformer ResultTransformer; private readonly ISessionBuilder _sessionBuilder;   static PopularProductsQuery() { ResultTransformer = Transformers.AliasToBean<PopularProduct>(); }   public PopularProductsQuery(ISessionBuilder sessionBuilder) { _sessionBuilder = sessionBuilder; }   public IList<PopularProduct> GetPopularProducts(DateTime startDate, int maxResults) { var session = _sessionBuilder.GetSession(); var popularProducts = session .GetNamedQuery("GetPopularProducts") .SetCacheable(true) .SetCacheRegion("PopularProductsCacheRegion") .SetCacheMode(CacheMode.Normal) .SetReadOnly(true) .SetResultTransformer(ResultTransformer) .SetParameter("StartDate", startDate.Date) .SetParameter("MaxResults", maxResults) .List<PopularProduct>();   return popularProducts; } }  Okay, so let's look at each line of the query execution. The first, GetNamedQuery, matches up with our NHibernate mapping for the sql-query. Next, we set it as cacheable (this is probably redundant since our mapping also specified it, but it can't hurt, right?). Then we set the cache region which we'll get to in the next section. Set the cache mode (optional, I believe), and my cache is read-only, so I set that as well. The result transformer is very important. This tells NHibernate how to transform your query results into a non-persistent entity. You can see I've defined ResultTransformer in the static constructor using the AliasToBean transformer. The name is obviously leftover from Java/Hibernate. Finally, set your parameters and then call a result method which will execute the query. Because this is set to cached, you execute this statement every time you run the query and NHibernate will know based on your parameters whether to use its cached version or a fresh version. The Configuration – hibernate.cfg.xml and Web.config You need to explicitly enable second-level caching in your hibernate configuration: <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> <session-factory> [...] <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property> <property name="cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider,NHibernate.Caches.SysCache</property> <property name="cache.use_query_cache">true</property> <property name="cache.use_second_level_cache">true</property> [...] </session-factory> </hibernate-configuration> Both properties "use_query_cache" and "use_second_level_cache" are necessary. As this is for a web deployement, we're using SysCache which relies on ASP.NET's caching. Be aware of this if you're not deploying to the web! You'll have to use a different cache provider. We also need to tell our cache provider (in this cache, SysCache) about our caching region: <syscache> <cache region="PopularProductsCacheRegion" expiration="86400" priority="5" /> </syscache> Here I've set the cache to be valid for 24 hours. This XML snippet goes in your Web.config (or in a separate file referenced by Web.config, which helps keep things tidy). The Payoff That should be it! At this point, your queries should run once against the database for a given set of parameters and then use the cache thereafter until it expires. You can, of course, adjust settings to work in your particular environment. Testing Testing your application to ensure it is using the cache is a pain, but if you're like me, you want to know that it's actually working. It's a bit involved, though, so I'll create a separate post for it if comments indicate there is interest.

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  • ImportError: No module named gtk

    - by Rick_2047
    after the debacle a few hours back I managed to get a working desktop after using an ethernet cable and sudo apt-get install ubuntu-desktop But now when I try to run ubuntu software center from CLI this is what I get rick@Abigail:~$ sudo software-center Traceback (most recent call last): File "/usr/bin/software-center", line 34, in <module> import gtk ImportError: No module named gtk Any guesses how to fix this. The search box on synaptic is also missing. It has something to do with module named axi. I think the both are related.

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  • Named arguments (parameters) as a readability aid

    - by Damian Mehers
    A long time ago I programmed a lot in ADA, and it was normal to name arguments when invoking a function - SomeObject.DoSomething(SomeParameterName = someValue); Now that C# supports named arguments, I'm thinking about reverting to this habit in situations where it might not be obvious what an argument means. You might argue that it should always be obvious what an argument means, but if you have a boolean argument, and callers are passing in "true" or "false" then qualifying the value with the name makes the call site more readable. contentFetcher.DownloadNote(note, manual : true); I guess I could create Enums instead of using true or false (Manual, Automatic in this case). What do you think about occasionally using named arguments to make code easier to read?

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  • Entity Framework 5, separating business logic from model - Repository?

    - by bnice7
    I am working on my first public-facing web application and I’m using MVC 4 for the presentation layer and EF 5 for the DAL. The database structure is locked, and there are moderate differences between how the user inputs data and how the database itself gets populated. I have done a ton of reading on the repository pattern (which I have never used) but most of my research is pushing me away from using it since it supposedly creates an unnecessary level of abstraction for the latest versions of EF since repositories and unit-of-work are already built-in. My initial approach is to simply create a separate set of classes for my business objects in the BLL that can act as an intermediary between my Controllers and the DAL. Here’s an example class: public class MyBuilding { public int Id { get; private set; } public string Name { get; set; } public string Notes { get; set; } private readonly Entities _context = new Entities(); // Is this thread safe? private static readonly int UserId = WebSecurity.GetCurrentUser().UserId; public IEnumerable<MyBuilding> GetList() { IEnumerable<MyBuilding> buildingList = from p in _context.BuildingInfo where p.Building.UserProfile.UserId == UserId select new MyBuilding {Id = p.BuildingId, Name = p.BuildingName, Notes = p.Building.Notes}; return buildingList; } public void Create() { var b = new Building {UserId = UserId, Notes = this.Notes}; _context.Building.Add(b); _context.SaveChanges(); // Set the building ID this.Id = b.BuildingId; // Seed 1-to-1 tables with reference the new building _context.BuildingInfo.Add(new BuildingInfo {Building = b}); _context.GeneralInfo.Add(new GeneralInfo {Building = b}); _context.LocationInfo.Add(new LocationInfo {Building = b}); _context.SaveChanges(); } public static MyBuilding Find(int id) { using (var context = new Entities()) // Is this OK to do in a static method? { var b = context.Building.FirstOrDefault(p => p.BuildingId == id && p.UserId == UserId); if (b == null) throw new Exception("Error: Building not found or user does not have access."); return new MyBuilding {Id = b.BuildingId, Name = b.BuildingInfo.BuildingName, Notes = b.Notes}; } } } My primary concern: Is the way I am instantiating my DbContext as a private property thread-safe, and is it safe to have a static method that instantiates a separate DbContext? Or am I approaching this all wrong? I am not opposed to learning up on the repository pattern if I am taking the total wrong approach here.

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  • Where to generate data in an Entity-Component System?

    - by Mark Mandel
    So I'm making a small game where I generate 2D landscape using perlin noise when the game first loads. I've got it working in a OO way, but want to move over to an ES architecure, and I'm just struggling to work out the right place for the code that does the generation to go? In OO world, I have a World object which gets passes a coordinate value that is used as the seed for the perlin noise, and generates all the points for the land mass when the world is created. I'm thinking I need a World component with a coordinate field on it - that's an easy part. From there - is it right for a component to generate data when it's first initialised (or is that too OO?)? Or should a System be doing that instead, when the game first starts? Or... some other solution I'm not aware of? Thanks in advance for any guidance.

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