Introduction to MongoDB collection.getIndexes() Method

The getIndexes() method is a built-in method of MongoDB that can return all index information in a collection. It can be used to view all indexes defined in a collection, including default indexes and user-defined indexes. Additionally, it can be used to check the status of indexes and to verify that a collection has been correctly indexed.

Syntax

The syntax of the getIndexes() method is as follows:

db.collection.getIndexes()

Here, db.collection represents the name of the collection you want to query.

Use Cases

The getIndexes() method is suitable for the following use cases:

• To view all index information defined in a collection.
• To check the status of indexes and to verify that a collection has been correctly indexed.
• To optimize query performance.

Example

Suppose we have a collection named sales that contains the following documents:

{ "_id" : ObjectId("5f9d365e1c19d70914e3e3c3"), "item" : "apple", "price" : 0.5, "quantity" : 20 }
{ "_id" : ObjectId("5f9d365e1c19d70914e3e3c4"), "item" : "banana", "price" : 0.25, "quantity" : 10 }
{ "_id" : ObjectId("5f9d365e1c19d70914e3e3c5"), "item" : "orange", "price" : 0.75, "quantity" : 30 }

Now we can use the getIndexes() method to view all indexes in the sales collection:

> db.sales.getIndexes()
[
  {
    "v": 2,
    "key": {
      "_id": 1
    },
    "name": "_id_",
    "ns": "test.sales"
  }
]

In the above example, we can see that there is only one default index _id_ in the sales collection.

Conclusion

By using the getIndexes() method, you can view all index information defined in a collection. This can help you understand the status of indexes and verify that a collection has been correctly indexed. Additionally, it can be used to optimize query performance, especially when dealing with large amounts of data.