Postgresql 中文操作指南
Parameters
请参阅 Section 36.8.1 以了解参数的说明。
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;
典型应用程序是使用 WHENEVER NOT FOUND BREAK 来处理结果集中的循环:
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;
}