Restrictions on server side cursors in MySQL databases
- 2020-05-07 20:35:21
- OfStack
For example, if the client executes a query but is only interested in the first row, the remaining rows are not transmitted.
The cursor is read-only and cannot be used to update rows.
UPDATE WHERE CURRENT OF and DELETE WHERE CURRENT OF were not implemented because an updatable cursor was not supported.
The cursor is not maintained (it is no longer kept open after submission).
The cursor is insensitive.
The cursor is not scrollable.
The cursor is unnamed. The statement handler ACTS as the cursor ID.
Only one cursor can be opened for each preprocessing statement. If multiple cursors are required, multiple statements must be processed.
If statements are not supported in preprocessing mode, the cursor cannot be used on statements that generate result sets. Include CHECK TABLES, HANDLER READ and SHOW BINLOG EVENTS statements.
The cursor is read-only and cannot be used to update rows.
UPDATE WHERE CURRENT OF and DELETE WHERE CURRENT OF were not implemented because an updatable cursor was not supported.
The cursor is not maintained (it is no longer kept open after submission).
The cursor is insensitive.
The cursor is not scrollable.
The cursor is unnamed. The statement handler ACTS as the cursor ID.
Only one cursor can be opened for each preprocessing statement. If multiple cursors are required, multiple statements must be processed.
If statements are not supported in preprocessing mode, the cursor cannot be used on statements that generate result sets. Include CHECK TABLES, HANDLER READ and SHOW BINLOG EVENTS statements.