Implicit Status Checking

You can use the WHENEVER command, as at 6 in Figure 3-1, to have ALLBASE/SQL examine SQLCA values and cause a specific action to be taken. The WHENEVER command is a preprocessor directive that specifies the action to be taken if an error or warning condition occurs during each execution of the SQL command:

   EXEC SQL WHENEVER SQLERROR CONTINUE;

                     |        |

                     |        |

                     |        |

                     |        the action

                     |

                     the condition

Each WHENEVER command affects all ALLBASE/SQL commands that follow it in the source listing until another WHENEVER command is encountered.

If execution of the COMMIT WORK RELEASE command at 7 or the SELECT command at 8 causes an error condition, ALLBASE/SQL takes no special action. This occurs because the WHENEVER command shown above precedes the COMMIT WORK RELEASE and SELECT commands in the source listing.

The WHENEVER SQLERROR command at 6 turns off the implicit status checking of the WHENEVER SQLERROR command that appears earlier in the source listing:

   EXEC SQL WHENEVER SQLERROR goto 1000;

This WHENEVER command specifies where to pass control when an error occurs during execution of the CONNECT, BEGIN WORK, or COMMIT WORK commands.

Although you can use a WHENEVER command to have ALLBASE/SQL examine the values in certain fields of the SQLCA, you can also examine the values yourself, as discussed under "Explicit Status Checking" later in this chapter.