Introduction to MongoDB cursor.isClosed() Method

cursor.isClosed() is a cursor method in MongoDB that is used to check whether a cursor is closed or not.

Syntax

The syntax of cursor.isClosed() is as follows:

cursor.isClosed()

Use Cases

When querying MongoDB data with a cursor, there are often situations where we need to interrupt the query, such as filtering specific data in the query results for processing or passing the query results as a parameter to other methods. In these cases, we need to manually close the cursor after processing the data to release resources, and the cursor.isClosed() method provides a convenient way to check whether the cursor is closed or not, so that we can take appropriate action when necessary.

Example

Suppose we have a database named test that contains a collection named users, and each document in the collection contains a name field and an age field. We can create a cursor object and perform a query using the following code:

cursor = db.users.find({ age: { $gt: 20 } })

Next, we use the cursor.isClosed() method to check whether the cursor is closed, as shown below:

print(cursor.isClosed())

When the cursor is not closed, the above code will output False, otherwise it will output True.

To demonstrate how to manually close a cursor and use the cursor.isClosed() method to check whether the cursor is closed, we can modify the above code as follows:

cursor = db.users.find({ age: { $gt: 20 } })

...
cursor.close()
print(cursor.isClosed())

In the above code, we manually close the cursor and use the cursor.isClosed() method to check whether the cursor is closed. If the cursor is closed, the above code will output True, otherwise it will output False.

Conclusion

The cursor.isClosed() method is a cursor method in MongoDB that is used to check whether a cursor is closed or not. When querying MongoDB data with a cursor, we often need to manually close the cursor to release resources, and the cursor.isClosed() method can help us conveniently check whether the cursor is closed or not, so that we can take appropriate action when necessary.