How to create indexes in MongoDB via .NET

问题

I've programmatically created a new document collection using the MongoDB C# driver.

At this point I want to create and build indexes programmatically. How can I do that?

回答1:

Starting from v2.0 of the driver there's a new async-only API. The old API should no longer be used as it's a blocking facade over the new API and is deprecated.

The currently recommended way to create an index is by calling and awaiting CreateOneAsync with an IndexKeysDefinition you get by using Builders.IndexKeys:

static async Task CreateIndex()
{
    var client = new MongoClient();
    var database = client.GetDatabase("HamsterSchool");
    var collection = database.GetCollection<Hamster>("Hamsters");
    await collection.Indexes.CreateOneAsync(Builders<Hamster>.IndexKeys.Ascending(_ => _.Name));
}

回答2:

you should use CreateIndex as EnsureIndex is marked obsolete for future compatibility with the next versions of MongoDB:

var client = new MongoClient("mongodb://localhost");
var db = client.GetServer().GetDatabase("db");
var collection = db.GetCollection<Hamster>("Hamsters");

collection.CreateIndex(IndexKeys<Hamster>.Ascending(_ => _.Name));

回答3:

Something like this should do:

var server = MongoServer.Create("mongodb://localhost");
var db = server.GetDatabase("myapp");

var users = db.GetCollection<User>("users");

users.EnsureIndex(new IndexKeysBuilder().Ascending("EmailAddress"));

Please see the following bits in the documentation:

http://api.mongodb.org/csharp/current/html/06bcd201-8844-3df5-d170-15f2b423675c.htm

回答4:

The overload of CreateOneAsync in the currently accepted answer is now marked as obsolete with the message "Use CreateOneAsync with a CreateIndexModel instead." Here's how you do it:

static async Task CreateIndex(string connectionString)
{
    var client = new MongoClient(connectionString);
    var database = client.GetDatabase("HamsterSchool");
    var collection = database.GetCollection<Hamster>("Hamsters");
    var indexOptions = new CreateIndexOptions();
    var indexKeys = Builders<Hamster>.IndexKeys.Ascending(hamster => hamster.Name);
    var indexModel = new CreateIndexModel<Hamster>(indexKeys, indexOptions);
    await collection.Indexes.CreateOneAsync(indexModel);
}

回答5:

There is an entire area on Indexing under the Definitions and Builders documentation page:

http://mongodb.github.io/mongo-csharp-driver/2.4/reference/driver/definitions/#index-keys

Example:

IndexKeysDefinition<MyModel> keys = "{ Reference: 1 }";
var indexModel = new CreateIndexModel<MyModel>(keys);
await _context.Indexes.CreateOneAsync(indexModel);

回答6:

the easiest way to create indexes in c# is by using the driver wrapper library MongoDB.Entities. here's an example of creating a text index:

    DB.Index<Author>()
      .Key(a => a.Name, Type.Text)
      .Key(a => a.Surname, Type.Text)
      .Create();

and to do a full-text search, you simply do:

    DB.SearchText<Author>("search term");

haven't seen anything else that makes it simpler than that.

来源：https://stackoverflow.com/questions/17807577/how-to-create-indexes-in-mongodb-via-net

标签

.net

mongodb

indexing

mongodb-.net-driver