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I need to change the storage schema of the entities on runtime. I've followed a wonderful post, available here: http://blogs.microsoft.co.il/blogs/idof/archive/2008/08/22/change-entity-framework-storage-db-schema-in-runtime.aspx?CommentPosted=true#commentmessage
This works perfectly, but only for queries, not for modifications.
Any idea why?
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First step is to create a partial class that allows you to pass a value to the constructor of your entities, by default it uses the values from your config file. Next create the function that will modify your store schema . ssdl file in memory.
You must own the schema to use ALTER SCHEMA . To rename a schema you must also have the CREATE privilege for the database. To alter the owner, you must also be a direct or indirect member of the new owning role, and you must have the CREATE privilege for the database.
When a schema is changed, it creates a ripple through all the applications that depend on that schema. With relational databases, a schema change can take weeks for developers to deal with while they adapt their code to the new model.
Well, I was looking for this piece of code all around the Internet. In the end I had to do it myself. It's based on Brandon Haynes adapter, but this function is all you need to change the schema on runtime - and you don't need to replace the autogenerated context constructors.
public static EntityConnection Create( string schema, string connString, string model) { XmlReader[] conceptualReader = new XmlReader[] { XmlReader.Create( Assembly .GetExecutingAssembly() .GetManifestResourceStream(model + ".csdl") ) }; XmlReader[] mappingReader = new XmlReader[] { XmlReader.Create( Assembly .GetExecutingAssembly() .GetManifestResourceStream(model + ".msl") ) }; var storageReader = XmlReader.Create( Assembly .GetExecutingAssembly() .GetManifestResourceStream(model + ".ssdl") ); XNamespace storageNS = "http://schemas.microsoft.com/ado/2009/02/edm/ssdl"; var storageXml = XElement.Load(storageReader); foreach (var entitySet in storageXml.Descendants(storageNS + "EntitySet")) { var schemaAttribute = entitySet.Attributes("Schema").FirstOrDefault(); if (schemaAttribute != null) { schemaAttribute.SetValue(schema); } } storageXml.CreateReader(); StoreItemCollection storageCollection = new StoreItemCollection( new XmlReader[] { storageXml.CreateReader() } ); EdmItemCollection conceptualCollection = new EdmItemCollection(conceptualReader); StorageMappingItemCollection mappingCollection = new StorageMappingItemCollection( conceptualCollection, storageCollection, mappingReader ); var workspace = new MetadataWorkspace(); workspace.RegisterItemCollection(conceptualCollection); workspace.RegisterItemCollection(storageCollection); workspace.RegisterItemCollection(mappingCollection); var connectionData = new EntityConnectionStringBuilder(connString); var connection = DbProviderFactories .GetFactory(connectionData.Provider) .CreateConnection(); connection.ConnectionString = connectionData.ProviderConnectionString; return new EntityConnection(workspace, connection); } The resulting EntityConnection should be passed as a parameter when instantiating the context. You can modify it, so all ssdl models are modified by this function, not only the specified one.
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