To process SQL statements, the stored procedure process assigns a memory segment to store context association. Cursors are handles or pointers to context regions. With cursors, stored procedures can control alterations in context regions.
If JDBC is used to call a stored procedure whose returned value is a cursor, the returned cursor cannot be used.
Cursors are classified into explicit cursors and implicit cursors. Table 1 shows the usage conditions of explicit and implicit cursors for different SQL statements.