Search Results

Search found 9916 results on 397 pages for 'entity component'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 25/397 | < Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >

  • Entity Framework 4 missing features?

    - by Roger Alsing
    I'm well aware that similair topics have been brought up before e.g. http://stackoverflow.com/questions/1639043/entity-framework-4-vs-nhibernate But instead of arguments like: NHibernate have been around longer and is more mature EF4 is drag n drop and not enterprisy EF4 and LinqToSql are ... I would like to see a more detailed list of features that you consider missing from EF4. Personally, I think the lack of enum support is the biggest drawback of EF4.

    Read the article

  • Entity Data Model Wizzard not creating tables in EDMX file

    - by Shawn
    I'm trying the database first approach by creating an ADO.NET Entity Data Model using the Wizard with the Adventureworks2012 DB. Testing DB connection works, and the connection string is added to the App.Config. I'm selecting all the tables except the ones marked as (dbo) AWBuildVersion, DatabaseLog, and ErrorLog. When the Wizard finishes the .edmx file is blank, and if I view the file in XML view the EntityContainer is empty. I'm using VS 2010 & .NET Framework 4.0

    Read the article

  • Association end is not mapped in ADO entity framework

    - by Sean
    I am just starting out with ADO.net Entity Framework I have mapped two tables together and receive the following error: Error 1 Error 11010: Association End 'OperatorAccess' is not mapped. E:\Visual Studio\projects\Brandi II\Brandi II\Hospitals.edmx 390 11 Brandi II Not sure what it is I am doing wrong

    Read the article

  • select top 5 in entity framework

    - by fishiefishie
    I have [Person] PersonID, EmailAddress, FirstName, LastName [OnlineAccount] OnlineAccountID, PersonID, Nickname Each person is allowed to have 0-* OnlineAccount. In entity framework with C#, how do I select the top 5 Person that has the most accounts?

    Read the article

  • Repository Pattern: SaveOrUpdate() in Entity Framework and L2S

    - by JMSA
    These web articles uses separate Save() and Update() methods in the repository pattern. I am using repository pattern. How can I write a SaveOrUpdate() method in Entity Framework with the help of ObjectContext and in Linq-To-SQL with the help of DataContext? That is, how can I write a single method that shall do both save and update job?

    Read the article

  • one or more Entity models for one database for entity framework?

    - by KentZhou
    When use entity framework for DAL tier, VS 2010 can create edmx for each database. Question: If I have a database with many tables, should I create only one edmx for all tables or mutiple edmx files? for example, maybe all security tables for one edmx file, other tables for another edmx file. If there is more than one, then in other tiers, there will have more then on ObjectContext in code for business logic. Which one it the best solution for this case?

    Read the article

  • Entity Framework .. partial constructor

    - by adamjellyit
    Hi .. I intend to extend the constructors of some of the entities in my Entity Framework (4). However how do I ensure that my constructor is run after the model has run its. i.e. I want to ensure that the the object holds the data from the database before I work on it in my constructor.

    Read the article

  • 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?

    Read the article

  • 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

    Read the article

  • 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?

    Read the article

  • 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?

    Read the article

  • Row Number Transformation

    The Row Number Transformation calculates a row number for each row, and adds this as a new output column to the data flow. The column number is a sequential number, based on a seed value. Each row receives the next number in the sequence, based on the defined increment value. The final row number can be stored in a variable for later analysis, and can be used as part of a process to validate the integrity of the data movement. The Row Number transform has a variety of uses, such as generating surrogate keys, or as the basis for a data partitioning scheme when combined with the Conditional Split transformation. Properties Property Data Type Description Seed Int32 The first row number or seed value. Increment Int32 The value added to the previous row number to make the next row number. OutputVariable String The name of the variable into which the final row number is written post execution. (Optional). The three properties have been configured to support expressions, or they can set directly in the normal manner. Expressions on components are only visible on the hosting Data Flow task, not at the individual component level. Sometimes the data type of the property is incorrectly set when the properties are created, see the Troubleshooting section below for details on how to fix this. Installation The component is provided as an MSI file which you can download and run to install it. This simply places the files on disk in the correct locations and also installs the assemblies in the Global Assembly Cache as per Microsoft’s recommendations. You may need to restart the SQL Server Integration Services service, as this caches information about what components are installed, as well as restarting any open instances of Business Intelligence Development Studio (BIDS) / Visual Studio that you may be using to build your SSIS packages. For 2005/2008 Only - Finally you will have to add the transformation to the Visual Studio toolbox manually. Right-click the toolbox, and select Choose Items.... Select the SSIS Data Flow Items tab, and then check the Row Number transformation in the Choose Toolbox Items window. This process has been described in detail in the related FAQ entry for How do I install a task or transform component? We recommend you follow best practice and apply the current Microsoft SQL Server Service pack to your SQL Server servers and workstations, and this component requires a minimum of SQL Server 2005 Service Pack 1. Downloads The Row Number Transformation  is available for SQL Server 2005, SQL Server 2008 (includes R2) and SQL Server 2012. Please choose the version to match your SQL Server version, or you can install multiple versions and use them side by side if you have more than one version of SQL Server installed. Row Number Transformation for SQL Server 2005 Row Number Transformation for SQL Server 2008 Row Number Transformation for SQL Server 2012 Version History SQL Server 2012 Version 3.0.0.6 - SQL Server 2012 release. Includes upgrade support for both 2005 and 2008 packages to 2012. (5 Jun 2012) SQL Server 2008 Version 2.0.0.5 - SQL Server 2008 release. (15 Oct 2008) SQL Server 2005 Version 1.2.0.34 – Updated installer. (25 Jun 2008) Version 1.2.0.7 - SQL Server 2005 RTM Refresh. SP1 Compatibility Testing. Added the ability to reuse an existing column to hold the generated row number, as an alternative to the default of adding a new column to the output. (18 Jun 2006) Version 1.2.0.7 - SQL Server 2005 RTM Refresh. SP1 Compatibility Testing. Added the ability to reuse an existing column to hold the generated row number, as an alternative to the default of adding a new column to the output. (18 Jun 2006) Version 1.0.0.0 - Public Release for SQL Server 2005 IDW 15 June CTP (29 Aug 2005) Screenshot Code Sample The following code sample demonstrates using the Data Generator Source and Row Number Transformation programmatically in a very simple package. Package package = new Package(); package.Name = "Data Generator & Row Number"; // Add the Data Flow Task Executable taskExecutable = package.Executables.Add("STOCK:PipelineTask"); // Get the task host wrapper, and the Data Flow task TaskHost taskHost = taskExecutable as TaskHost; MainPipe dataFlowTask = (MainPipe)taskHost.InnerObject; // Add Data Generator Source IDTSComponentMetaData100 componentSource = dataFlowTask.ComponentMetaDataCollection.New(); componentSource.Name = "Data Generator"; componentSource.ComponentClassID = "Konesans.Dts.Pipeline.DataGenerator.DataGenerator, Konesans.Dts.Pipeline.DataGenerator, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b2ab4a111192992b"; CManagedComponentWrapper instanceSource = componentSource.Instantiate(); instanceSource.ProvideComponentProperties(); instanceSource.SetComponentProperty("RowCount", 10000); // Add Row Number Tx IDTSComponentMetaData100 componentRowNumber = dataFlowTask.ComponentMetaDataCollection.New(); componentRowNumber.Name = "FlatFileDestination"; componentRowNumber.ComponentClassID = "Konesans.Dts.Pipeline.RowNumberTransform.RowNumberTransform, Konesans.Dts.Pipeline.RowNumberTransform, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b2ab4a111192992b"; CManagedComponentWrapper instanceRowNumber = componentRowNumber.Instantiate(); instanceRowNumber.ProvideComponentProperties(); instanceRowNumber.SetComponentProperty("Increment", 10); // Connect the two components together IDTSPath100 path = dataFlowTask.PathCollection.New(); path.AttachPathAndPropagateNotifications(componentSource.OutputCollection[0], componentRowNumber.InputCollection[0]); #if DEBUG // Save package to disk, DEBUG only new Application().SaveToXml(String.Format(@"C:\Temp\{0}.dtsx", package.Name), package, null); #endif package.Execute(); foreach (DtsError error in package.Errors) { Console.WriteLine("ErrorCode : {0}", error.ErrorCode); Console.WriteLine(" SubComponent : {0}", error.SubComponent); Console.WriteLine(" Description : {0}", error.Description); } package.Dispose(); Troubleshooting Make sure you have downloaded the version that matches your version of SQL Server. We offer separate downloads for SQL Server 2005, SQL Server 2008 and SQL Server 2012. If you get an error when you try and use the component along the lines of The component could not be added to the Data Flow task. Please verify that this component is properly installed.  ... The data flow object "Konesans ..." is not installed correctly on this computer, this usually indicates that the internal cache of SSIS components needs to be updated. This is held by the SSIS service, so you need restart the the SQL Server Integration Services service. You can do this from the Services applet in Control Panel or Administrative Tools in Windows. You can also restart the computer if you prefer. You may also need to restart any current instances of Business Intelligence Development Studio (BIDS) / Visual Studio that you may be using to build your SSIS packages. Once installation is complete you need to manually add the task to the toolbox before you will see it and to be able add it to packages - How do I install a task or transform component? Please also make sure you have installed a minimum of SP1 for SQL 2005. The IDtsPipelineEnvironmentService was added in SQL Server 2005 Service Pack 1 (SP1) (See  http://support.microsoft.com/kb/916940). If you get an error Could not load type 'Microsoft.SqlServer.Dts.Design.IDtsPipelineEnvironmentService' from assembly 'Microsoft.SqlServer.Dts.Design, Version=9.0.242.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91'. when trying to open the user interface, it implies that your development machine has not had SP1 applied. Very occasionally we get a problem to do with the properties not being created with the correct data type. Since there is no way to programmatically to define the data type of a pipeline component property, it can only infer it. Whilst we set an integer value as we create the property, sometimes SSIS decides to define it is a decimal. This is often highlighted when you use a property expression against the property and get an error similar to Cannot convert System.Int32 to System.Decimal. Unfortunately this is beyond our control and there appears to be no pattern as to when this happens. If you do have more information we would be happy to hear it. To fix this issue you can manually edit the package file. In Visual Studio right click the package file from the Solution Explorer and select View Code, which will open the package as raw XML. You can now search for the properties by name or the component name. You can then change the incorrect property data types highlighted below from Decimal to Int32. <component id="37" name="Row Number Transformation" componentClassID="{BF01D463-7089-41EE-8F05-0A6DC17CE633}" … >     <properties>         <property id="38" name="UserComponentTypeName" …>         <property id="41" name="Seed" dataType="System.Int32" ...>10</property>         <property id="42" name="Increment" dataType="System.Decimal" ...>10</property>         ... If you are still having issues then contact us, but please provide as much detail as possible about error, as well as which version of the the task you are using and details of the SSIS tools installed.

    Read the article

  • 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

    Read the article

  • Creating, using and managing XML component dictionaries quick tutorials

    - by drrwebber
    XML Component Dictionary capabilities are provided in conjunction with the CAM Editor toolset.  These dictionaries accelerate the development of consistent XML information exchanges using standard sets of dictionary components. The quick tutorials are aimed at showing the 'how to' of the basic capabilities to jump start use of XML dictionaries with the CAM Editor. The collection of dictionary tutorials videos run for a total of approximately 20 minutes.  Each video can be reviewed individually also. Learn how to use the dictionary functions to create dictionaries by harvesting data model components from existing XSD schema, SQL database table schema, or simple Excel / Open Office spreadsheets with tables of components listed.Also included are tips and functions relating to use of NIEM exchange development, IEPD and EIEM techniques.These videos should be viewed in conjunction with reviewing the overall concepts and techniques described in the companion video on the CAM Editor and Dictionaries overview.  The approach is aligned with OASIS and Core Components Technical Specification (CCTS) standards specifications for XML components and dictionaries.Dictionary collections can be stored locally on the file system, or local network, or collaboratively on the web or cloud deployment, or can be shared and managed securely using the Oracle Enterprise Repository (OER) tool. Also included are techniques relating to the use of the NIEM approach for developing XML exchange schema and IEPD packages.  This includes generating reuse scores, wantlist, and cross reference spreadsheets. Included in the latest release of the CAM Editor is the ability to use the analyse dictionary tool to determine duplicate components, conflicting component definitions, missing component descriptions and so on.  This ensures high quality dictionary component specifications.  Using the CAM Editor you can also create MindMap models and UML physical models of your dictionary components sets. For a complete guide to using the CAM Editor see the main YouTube video tutorials website and the CAM Editor website.

    Read the article

  • 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?

    Read the article

  • 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)

    Read the article

  • 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.

    Read the article

  • 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 }

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >