Adminstration

The administration operations exist in multiple places in the driver’s API. Database-related operations exist on the database object and collection-related operations exist on the collection object. If there isn’t a method for the admin operation you want to use, you can run a command directly using the RunCommand or RunCommandAsync methods on IMongoDatabase is available.

Databases

These operations exist on the IMongoClient interface.

Getting a database

To get a database, use the GetDatabase.

// get the test database
var db = client.GetDatabase("test");

Dropping a database

Use the DropDatabase or DropDatabaseAsync methods.

// drops the test database
client.DropDatabase("test");

// drops the test database
await client.DropDatabaseAsync("test");

Listing the databases

Use the ListDatabases or ListDatabasesAsync methods.

using (var cursor = client.ListDatabase())
{
    var list = cursor.ToList();
    // do something with the list
}

using (var cursor = await client.ListDatabaseAsync())
{
    var list = await cursor.ToListAsync();
    // do something with the list
}

Collections

These operations exist on the IMongoDatabase interface.

Getting a collection

The GetCollection<TDocument> method returns an IMongoCollection<TDocument>.

The generic parameter on the method defines the schema your application will use when working with the collection. Generally, this type will either be a BsonDocument which provides no schema enforcement or a mapped class (POCO).

// gets a collection named "foo" using a BsonDocument
var collection = db.GetCollection<BsonDocument>("foo");

For more information on working with collections, see the CRUD Operations section.

Creating a collection

Just like databases, there is no need to create a collection before working with it. It will be created upon first use. However, certain features of collections require explicit creation. The CreateCollection and CreateCollectionAsync methods allows you to specify not only a name, but also CreateCollectionOptions.

var options = new CreateCollectionOptions
{
    Capped = true,
    MaxSize = 10000
};

// creates a capped collection named "foo" with a maximum size of 10,000 bytes
db.CreateCollection("foo", options); 

// creates a capped collection named "foo" with a maximum size of 10,000 bytes
await db.CreateCollectionAsync("foo", options); 

Creating a clustered collection

New in MongoDB 5.3. Clustered collections are collections created with a clustered index. Documents in a clustered collection are ordered by the clustered index key value. To create a clustered collection:

var options = new CreateCollectionOptions<Product>
{
    ClusteredIndex = new ClusteredIndexOptions<Product>()
};
db.CreateCollection("product", options);

Dropping a collection

Use the DropCollection or DropCollectionAsync methods.

// drops the "foo" collection
db.DropCollection("test");

// drops the "foo" collection
await db.DropCollectionAsync("test");

Listing the collections

Use the ListCollections or ListCollectionsAsync methods.

using (var cursor = db.ListCollections())
{
    var list = cursor.ToList();
    // do something with the list
}

using (var cursor = await db.ListCollectionsAsync())
{
    var list = await cursor.ToListAsync();
    // do something with the list
}

Renaming a collection

Use the RenameCollection or RenameCollectionAsync methods.

// rename the "foo" collection to "bar"
db.RenameCollection("foo", "bar");

// rename the "foo" collection to "bar"
await db.RenameCollectionAsync("foo", "bar");

Indexes

IMongoCollection<T> contains an Indexes property which gives access to all the index-related operations for a collection.

A number of the methods take an IndexKeysDefinition<TDocument>. See the documentation on the index keys builder for more information.

Creating an index

Use the CreateOne or CreateOneAsync methods to create a single index. For instance, to create an ascending index on the “x” and “y” fields,

collection.Indexes.CreateOne("{ x : 1, y : 1 }");

// or

collection.Indexes.CreateOne(new BsonDocument("x", 1).Add("y", 1));

// or

collection.Indexes.CreateOne(Builders<BsonDocument>.IndexKeys.Ascending("x").Ascending("y"));

await collection.Indexes.CreateOneAsync("{ x : 1, y : 1 }");

// or

await collection.Indexes.CreateOneAsync(new BsonDocument("x", 1).Add("y", 1));

// or

await collection.Indexes.CreateOneAsync(Builders<BsonDocument>.IndexKeys.Ascending("x").Ascending("y"));

In addition, there are a number of options available when creating index. These are present on the optional CreateIndexOptions parameter. For instance, to create a unique ascending index on “x”:

var options = new CreateIndexOptions { Unique = true };

collection.Indexes.CreateOne("{ x : 1 }", options);

await collection.Indexes.CreateOneAsync("{ x : 1 }", options);

Also, there is a generic CreateIndexOptions<TDocument> which extends the non-generic version and provides a number of additional options available when creating an index. For example, to create a wildcard projection index on “name” and “description.text”, do the following:

Given the following classes:

public class Description
{
    [BsonElement("text")]
    public string Text { get; set; }
}

public class Widget
{
    public ObjectId Id { get; set; }

    [BsonElement("name")]
    public int Name { get; set; }

    [BsonElement("description")]
    public Description Description { get; set; }
}

The wildcard projection value can be implicitly convertible from both a JSON string as well as a BsonDocument.

var options = new CreateIndexOptions<Widget>();

options.WildcardProjection = "{ 'name' : 1, 'description.text' : 1 }";

//or

options.WildcardProjection = new BsonDocument { { "name", 1 }, { "description.text", 1 } };

We can achieve the same result with using a projection builder:

options.WildcardProjection = Builders<Widget>.Projection.Include(x => x.Name).Include(x => x.Description.Text);

Dropping an index

To drop a single index use the DropOne or DropOneAsync methods.

// drop the index named "x_1";
collection.Indexes.DropOne("x_1");

// drop the index named "x_1";
await collection.Indexes.DropOneAsync("x_1");

To drop all indexes use the DropAll or DropAllAsync methods

// drop all indexes
collection.Indexes.DropAll();

// drop all indexes
await collection.Indexes.DropAllAsync();

Listing indexes

To list all the indexes in a collection, use the List or ListAsync methods.

using (var cursor = collection.Indexes.List())
{
    var list = cursor.ToList();
    // do something with the list...
}

using (var cursor = await collection.Indexes.ListAsync())
{
    var list = await cursor.ToListAsync();
    // do something with the list...
}