In computer science, a database cursor is a control structure that enables traversal over the records in a database.Cursors facilitate subsequent processing in conjunction with the traversal, such as retrieval, addition and removal of database records.You cannot specify multiple collations for an operation.For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort.
You cannot have an array filter document for an identifier if the identifier is not included in the update document.
The database cursor characteristic of traversal makes cursors akin to the programming language concept of iterator.
Cursors are used by database programmers to process individual rows returned by database system queries.
With a non-scrollable (or forward-only) cursor, you can each row at most once, and the cursor automatically moves to the next row.
After you fetch the last row, if you fetch again, you will put the cursor after the last row and get the following code: SQLSTATE 02000 (SQLCODE 100).