c# Entity Framework EF 4.1 Wijzig schema en databasenaam tijdens runtime

Eigenlijk had ik hier ook een oplossing voor nodig. Ik heb snel een oplossing bedacht, die goed werkt. Ik heb hier niet veel informatie over gevonden op internet, dus ik ben niet zeker van de "EF 4.1 wordt geleverd met betere ondersteuningstools om dit te doen".

Het concrete voorbeeld "Schemanaam wijzigen in runtime - Entiteitsframework" werkte niet helemaal voor mij, maar met enkele kleine aanpassingen kreeg ik het werkend.

Hier is een DatabaseUtils-klasse die het kan:

internal static class DatabaseUtils
{
    /// <summary>
    /// Builds the connection string for Entity framework.
    /// </summary>
    /// <returns></returns>
    public static EntityConnection BuildConnection(BuildConnectionParams buildConnectionParams)
    {
        var sqlBuilder = new SqlConnectionStringBuilder
            {
                DataSource = buildConnectionParams.ServerName,
                InitialCatalog = buildConnectionParams.DatabaseName,
                IntegratedSecurity = true
            };

        var providerString = sqlBuilder.ToString();
        var entityBuilder = new EntityConnectionStringBuilder
        {
            Provider = buildConnectionParams.ProviderName,
            ProviderConnectionString = providerString,
            Metadata = string.Format(@"res://*/{0}.csdl|
                        res://*/{0}.ssdl|
                        res://*/{0}.msl", buildConnectionParams.ModelName)
        };

        return CreateConnection(buildConnectionParams.SchemaName, entityBuilder, buildConnectionParams.ModelName);
    }


    /// <summary>
    /// Creates the EntityConnection, based on new schema & existing connectionString
    /// </summary>
    /// <param name="schemaName">Name of the schema.</param>
    /// <param name="connectionBuilder"></param>
    /// <param name="modelName">Name of the model.</param>
    /// <returns></returns>
    private static EntityConnection CreateConnection(string schemaName, EntityConnectionStringBuilder connectionBuilder, string modelName)
    {
        Func<string, Stream> generateStream =
            extension => Assembly.GetExecutingAssembly().GetManifestResourceStream(string.Concat(modelName, extension));

        Action<IEnumerable<Stream>> disposeCollection = streams =>
        {
            if (streams == null)
                return;

            foreach (var stream in streams.Where(stream => stream != null))
                stream.Dispose();
        };

        var conceptualReader = generateStream(".csdl");
        var mappingReader = generateStream(".msl");
        var storageReader = generateStream(".ssdl");

        if (conceptualReader == null || mappingReader == null || storageReader == null)
        {
            disposeCollection(new[] { conceptualReader, mappingReader, storageReader });
            return null;
        }

        var storageXml = XElement.Load(storageReader);

        foreach (var entitySet in storageXml.Descendants())
        {
            var schemaAttribute = entitySet.Attributes("Schema").FirstOrDefault();
            if (schemaAttribute != null)
                schemaAttribute.SetValue(schemaName);
        }

        storageXml.CreateReader();

        var workspace = new MetadataWorkspace();

        var storageCollection = new StoreItemCollection(new[] { storageXml.CreateReader() });
        var conceptualCollection = new EdmItemCollection(new[] { XmlReader.Create(conceptualReader) });
        var mappingCollection = new StorageMappingItemCollection(conceptualCollection, 
                                                                storageCollection,
                                                                new[] { XmlReader.Create(mappingReader) });

        workspace.RegisterItemCollection(conceptualCollection);
        workspace.RegisterItemCollection(storageCollection);
        workspace.RegisterItemCollection(mappingCollection);

        var connection = DbProviderFactories.GetFactory(connectionBuilder.Provider).CreateConnection();
        if (connection == null)
        {
            disposeCollection(new[] { conceptualReader, mappingReader, storageReader });
            return null;
        }

        connection.ConnectionString = connectionBuilder.ProviderConnectionString;
        return new EntityConnection(workspace, connection);
    }
}

Gebruik:

/// <summary>
/// Initializes a new instance of the <see cref="DynamicAQDContext"/> class.
/// </summary>
public DynamicAQDContext()
{
    var entityConnection = DatabaseUtils.BuildConnection(new BuildConnectionParams
    {
        ProviderName = "System.Data.SqlClient",
        ServerName = "localhost\\",
        DatabaseName = "",
        ModelName = "YOURMODEL",
        SchemaName = "SCHEMA"
    });

    if(entityConnection == null)
        throw new Exception("Can't create EntityConnection");

    _entities = new LINKEntities(entityConnection);
}

meer info is hier te vinden:http:/ /bestplayah.com/entity-framework-dynamic-schema-changes-using-database-first-approach/