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Marten as Document Db Edit on GitHub


Many of the Marten contributors were fans of the existing RavenDb database, but wanted a more robust underlying technology. To that end, Marten was largely conceived of as a way to efficiently use the proven Postgresql database engine as a document database and act as a near drop-in replacement for RavenDb in several existing applications. As such, you may clearly see some influence from RavenDb on the Marten services and API's.

Document Store

To use Marten as a document database, you first need a Postgresql schema that will store your documents. Once you have that, getting started with Marten can be as simple as opening a DocumentStore to your new Postgresql schema:


var store = DocumentStore
    .For("host=localhost;database=marten_test;password=mypassword;username=someuser");

The code sample above sets up document storage against the Postgresql at the connection string you supplied. In this "quickstart" configuration, Marten will build new database tables and functions for each new document type as needed if those database schema objects do not already exist.

As of Marten v0.6, document storage tables will also be dropped and rebuilt if the actual database table does not match up with the document storage configuration. So if you add a searchable field or change the id type of a document type, Marten will regenerate the database schema objects when running with AutoCreateSchemaObjects = true.

While the default "auto-create" database schema objects is fantastic for a development time experience, you may not want Marten to be building out new database schema objects at production time. You might also want to override the default JSON serialization, tweak the document storage for performance, or opt into Postgresql 9.5's fancy new "upsert" capability. For customization, you have a different syntax for bootstrapping a DocumentStore:


var store = DocumentStore.For(_ =>
{
    // Turn this off in production 
    _.AutoCreateSchemaObjects = AutoCreate.None;

    // This is still mandatory
    _.Connection("some connection string");

    // Override the JSON Serialization
    _.Serializer<TestsSerializer>();
});

For more information on using the IDocumentStore and configuring document storage, see:

Querying and Loading Documents

Now that we've got a document store, we can use that to create a new IQuerySession object just for querying or loading documents from the database:


using (var session = store.QuerySession())
{
    var internalUsers = session
        .Query<User>().Where(x => x.Internal).ToArray();
}

For more information on the query support within Marten, see:

Persisting Documents

The main service for updating and persisting documents is the IDocumentSession. An IDocumentSession is created by your IDocumentStore from above in one of three ways:


// Open a session for querying, loading, and 
// updating documents 
using (var session = store.LightweightSession())
{
    var user = new User {FirstName = "Han", LastName = "Solo"};
    session.Store(user);

    session.SaveChanges();
}

// Open a session for querying, loading, and 
// updating documents with a backing "Identity Map"
using (var session = store.OpenSession())
{
    var existing = session
        .Query<User>()
        .Where(x => x.FirstName == "Han" && x.LastName == "Solo")
        .Single();
}

// Open a session for querying, loading, and 
// updating documents that performas automated
// "dirty" checking of previously loaded documents
using (var session = store.DirtyTrackedSession())
{
    
}

In all cases, IDocumentSession has the same query and loading functions as the read only IQuerySession.

For more information on persisting documents and the different underlying behavior of the three flavors of IDocumentSession above, see: