# db.collection.ensureIndex()

在本页面

* [定义](#definition)
* [附加信息](#additional-information)

## 定义

* `db.collection.` `ensureIndex`(键，选项)
  * *从3.0.0版开始不推荐使用：*`db.collection.ensureIndex()`现在是的别名 `db.collection.createIndex()`。

如果索引尚不存在，则在指定字段上创建索引。

## 附加信息

* 使用db.collection.createIndex()而不是db.collection.ensureIndex()来创建新索引。
* 本手册的索引部分用于 MongoDB 中索引和索引的完整文档。
* db.collection.getIndexes()查看集合的现有索引的规范。

译者：李冠飞

校对：


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