c# Entity Framework EF 4.1 Ubah Skema dan nama Database saat runtime

Sebenarnya, saya juga butuh solusi untuk ini. Saya dengan cepat menyiapkan solusi, yang berfungsi dengan baik. Saya tidak menemukan banyak informasi tentang ini di Internet, jadi saya tidak yakin tentang "EF 4.1 dilengkapi dengan alat pendukung yang lebih baik untuk melakukannya".

Contoh konkret "Mengubah nama skema saat runtime - Entity framework" tidak sepenuhnya berhasil untuk saya, namun dengan beberapa modifikasi kecil saya berhasil.

Berikut adalah kelas DatabaseUtils yang dapat melakukannya:

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);
    }
}

Penggunaan:

/// <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);
}

info lebih lanjut dapat ditemukan di sini:http:/ /bestplayah.com/entity-framework-dynamic-schema-changes-using-database-first-approach/