WHENEVER
Name
WHENEVER -- specify the action to be taken when an SQL statement causes a specific class condition to be raisedDescription
Define a behavior which is called on the special cases (Rows not found, SQL warnings or errors) in the result of SQL execution.
Examples
EXEC SQL WHENEVER NOT FOUND CONTINUE;EXEC SQL WHENEVER NOT FOUND DO BREAK;EXEC SQL WHENEVER SQLWARNING SQLPRINT;EXEC SQL WHENEVER SQLWARNING DO warn();EXEC SQL WHENEVER SQLERROR sqlprint;EXEC SQL WHENEVER SQLERROR CALL print2();EXEC SQL WHENEVER SQLERROR DO handle_error("select");EXEC SQL WHENEVER SQLERROR DO sqlnotice(NULL, NONO);EXEC SQL WHENEVER SQLERROR DO sqlprint();EXEC SQL WHENEVER SQLERROR GOTO error_label;EXEC SQL WHENEVER SQLERROR STOP;
A typical application is the use ofWHENEVER NOT FOUND BREAK to handle looping through result sets:
intmain(void){ EXEC SQL CONNECT TO testdb AS con1; EXEC SQL ALLOCATE DESCRIPTOR d; EXEC SQL DECLARE cur CURSOR FOR SELECT current_database(), 'hoge', 256; EXEC SQL OPEN cur; /* when end of result set reached, break out of while loop */ EXEC SQL WHENEVER NOT FOUND DO BREAK; while (1) { EXEC SQL FETCH NEXT FROM cur INTO SQL DESCRIPTOR d; ... } EXEC SQL CLOSE cur; EXEC SQL COMMIT; EXEC SQL DEALLOCATE DESCRIPTOR d; EXEC SQL DISCONNECT ALL; return 0;}