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Migration : Changes related to IDocumentSession

Namespace

IDocumentSession can be referenced using Raven.Client.Documents.Session (previously Raven.Client).

Load

Loading by value type ID

Since an entity identifier can be only string in RavenDB 4.0 the Load<T>(ValueType id) method overload accepting value types (int, Guid etc.) is no longer available. In order to load an entity having value type identifier you need to use a document identifier, that is a collection name concatenated with the value type ID.

3.x
User user = session.Load<User>(id);
4.0
User user = session.Load<User>("users/" + id);

Also User.Id property should be string.

Loading multiple documents

The signature of T[] Load<T>(IEnumerable<string> ids) method has been changed to Dictionary<string, T> Load<T>(IEnumerable<string> ids). The keys in the returned dictionary are identifiers of documents requested to be loaded. If a document with was not found then null is set in the dictionary under a given ID.

3.x
User[] users = session.Load<User>(new[] 
                    {
                        "users/1", "users/2" 
                    });
4.0
Dictionary<string, User> users = session.Load<User>(new[]
                                    {
                                        "users/1", "users/2"
                                    });

Loading with transformer

The Load method overloads accepting transformer name parameter and transformer types as generic have been removed since transformers was completely replaced by projections in RavenDB 4.0. You need to perform a query and specify a projection instead. The query will be handled very efficiently, directly by a collection storage index, it won't create regular RavenDB index.

3.x
var users = session.Load<Transformer, ProjectedUser>("users/1");
4.0
var users = session.Query<User>().Where(x => x.Id == "users/1")
                                 .Select(x => new ProjectedUser
                                 {
                                     FullName = x.Name,
                                 }).First();

Delete

Delete by value type ID

Also the Delete method no longer have the following overload Delete<T>(ValueType id). Please pass entity instance that you want to delete or the document identifier including collection name.

3.x
session.Delete<User>(id);
4.0
session.Delete(user);
session.Delete("users/" + id);

Delete by index

The method session.Advanced.DeleteByIndex has been removed. Use DeleteByQueryOperation operation instead.

3.x
Operation operation = 
    session
        .Advanced
        .DeleteByIndex<Person, Person_ByAge>(x => x.Age < 35);
4.0
Operation operation =
    store
        .Operations
        .Send(new DeleteByQueryOperation<Person, Person_ByAge>(x => x.Age < 35));

Streaming

The document streaming method accepting the document etag as the first parameter session.Advanced.Stream<T>(Etag fromEtag) no longer exists. As the streaming request can be processed by any node available in the cluster, the solution is to use Data Subscriptions in order to guarantee reliable processing of documents in the cluster environment.