System.Data.SQLite

Hi,

I am new to Entity Framework, and I am trying to create a new sqlite database. So I created the data model (edmx) file. Now how do I set the sqlite connection string that can talk to this edmx file? and how to do I create a new datacontext object that can create a new db? I have handled sqlite databases before, but never through entity framework.

I looked at the textlinq sample, but (I think) in that the database was already created and added as an 'existing item' and the corresponding connection string was written in the application config file.

Thanks.

 

Neither Entity Framework nor Visual Studio create databases from models ..... yet.

Thanks for the reply.

So how do I do these (if there is a way to do so)

- I can update the data model from the database, but can I do the reverse? i.e., if I make changes to the data model, e.g., add table, can I put those in the database?

- How do I programatically switch the database?

 

Amol

 

I could get the datacontext variable, but did not know what to do with it to achieve the above.

System.Data.SQLite.SQLiteConnection sq = new System.Data.SQLite.SQLiteConnection(@"Data Source=C:\dd.db;New=True;UTF8Encoding=True;Version=3");

System.Data.Linq.DataContext c = new System.Data.Linq.DataContext(sq);

Amol:

if I make changes to the data model, e.g., add table, can I put those in the database?

You need to do it manually. I would suggest you to change the database first, then update your model from database.

Amol:

How do I programatically switch the database?

You need to create another object context providing another connection string.

Amol:

System.Data.Linq.DataContext c = new System.Data.Linq.DataContext(sq);

DataContext is part of LINQ to SQL, which only officially supports SQL Server. You need to use Entity Framework. System.Data.Objects.ObjectContext is the Entity Framework equivalent to System.Data.Linq.DataContext. When you add a "ADO.NET Entity Data Model" item to your project, Visual Studio generates a class that inherits form System.Data.Object.ObjectContext.

Thanks a lot !! This helps a lot.

Just for  benefit for any other beginner (like me), here's how I did it:

 

System.Data.EntityClient.EntityConnectionStringBuilder ee = new System.Data.EntityClient.EntityConnectionStringBuilder();

ee.Provider = "System.Data.SQLite";

ee.Metadata = @"res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl";

ee.ProviderConnectionString = @"data source=C:\Mydata.db;Version=3;";

System.Data.EntityClient.EntityConnection my_entity = new System.Data.EntityClient.EntityConnection(ee.ConnectionString);

 

using (MydataEntities temp = new MydataEntities(my_entity))

{

}

 Something is not working out 100% for me with this. Can anyone provide a .zip of working code or a tutorial web page? I've made a few web search queries and have not found a full example yet.

 

 

Thanks.

 

I've made a class can easily create connect. Hope this can help you. Public Class iSqliteEntity Public Shared ReadOnly Property ConnectionString(ByVal Model As String, ByVal DataFilePath As String) Get Dim csBuilder As New System.Data.EntityClient.EntityConnectionStringBuilder csBuilder.Provider = "System.Data.SQLite" csBuilder.Metadata = "res://*/world.csdl|res://*/world.ssdl|res://*/world.msl".Replace("world", Model) csBuilder.ProviderConnectionString = "data source=" + DataFilePath + ";Version=3;" Return csBuilder.ConnectionString End Get End Property Public Shared ReadOnly Property Connect(ByVal Model As String, ByVal DataFilePath As String) As EntityClient.EntityConnection Get Return New EntityClient.EntityConnection(ConnectionString(Model, DataFilePath)) End Get End Property End Class