Cursor Declaration
Before a cursor can be used in an application, it must be declared. The syntax for declaring a cursor is:
EXEC SQL DECLARE cursor_name CURSOR FOR
select_statement;
The DECLARE CURSOR statement assigns a name to the cursor and associates the cursor with a SELECT statement to use to retrieve data. A cursor is always associated with a particular SELECT statement. The select is executed when the cursor is opened.
Updates can be performed only if the cursor's SELECT statement does not include any of the following elements:
• Aggregates
• Union clause
• Group by clause
• Having clause
• Distinct
These elements can be present in subselects within the SELECT statement, but must not occur in the outermost SELECT statement.
The
cursor_name can be specified using a string literal or a host language string variable. Cursor names can be assigned dynamically. For details, see
Example of Dynamically Specified Cursor Names.
Last modified date: 01/30/2023