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MongoDB C驱动程序创建索引

mongodb-.net-driver c#

StuiterSlurf Marius · 技术社区 · 6 年前

我刚把MongoDB从2.5.0版更新到2.7.0版。Visual Studio告诉我以下创建索引的方法已过时:

protected override Task OnPerformMaintenanceAsync(CancellationToken cancellationToken) =>
  NotificationLogs.Indexes.CreateOneAsync(Builders<NotificationLog>.IndexKeys.Ascending(_ => _.TimestampUtc));

它建议我使用 CreateIndexModel .

唯一的问题是,我找不到一个能起到同样作用的例子。

我试过:

protected Task OnPerformMaintenanceTestAsync(CancellationToken cancellationToken)
{
  // Old approach
  // var builder = Builders<NotificationLog>.IndexKeys.Ascending(x => x.TimestampUtc);

  // New approach
  var indexModel = new CreateIndexModel<NotificationLog>(nameof(NotificationLog.TimestampUtc));

  return NotificationLogs.Indexes.CreateOneAsync(indexModel);
}

但我有个例外:

System.FormatException: 'JSON reader was expecting a value but found 'TimestampUtc'.'

2 回复 | 直到 6 年前

StuiterSlurf Marius 6 年前

MongoDB 2.7驱动程序中的新方法是执行以下操作:

var notificationLogBuilder = Builders<NotificationLog>.IndexKeys;
var indexModel = new CreateIndexModel<NotificationLog>(notificationLogBuilder.Ascending(x => x.TimestampUtc));
await IMongoCollection.Indexes.CreateOneAsync(indexModel, cancellationToken: cancellationToken).ConfigureAwait(false);

-1

petey m 6 年前

以下是我的工作。

public async Task CreateIndexOnCollection(IMongoCollection<BsonDocument> collection, string field)
{
    var keys = Builders<BsonDocument>.IndexKeys.Ascending(field);
    await collection.Indexes.CreateOneAsync(keys);
}

或者,如果我们事先知道索引是什么,我们可以使用如下强类型实现:

public async Task CreateIndexOnNameField()
{
    var keys = Builders<User>.IndexKeys.Ascending(x => x.Name);
    await _usersCollection.Indexes.CreateOneAsync(keys);
}