## WHENEVER WHENEVER — specify the action to be taken when an SQL statement causes a specific class condition to be raised ## Synopsis ``` WHENEVER { NOT FOUND | SQLERROR | SQLWARNING } action ``` ## Description Define a behavior which is called on the special cases (Rows not found, SQL warnings or errors) in the result of SQL execution. ## Parameters See [Section 36.8.1](ecpg-errors.html#ECPG-WHENEVER) for a description of the parameters. ## Examples ``` EXEC SQL WHENEVER NOT FOUND CONTINUE; EXEC SQL WHENEVER NOT FOUND DO BREAK; EXEC SQL WHENEVER NOT FOUND DO CONTINUE; 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 of `WHENEVER NOT FOUND BREAK` to handle looping through result sets: ``` int main(void) { EXEC SQL CONNECT TO testdb AS con1; EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT; 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; } ``` ## Compatibility `WHENEVER` is specified in the SQL standard, but most of the actions are PostgreSQL extensions.