> Why sometimes tableupdate could not commit successfully? especially in the network environment?i already did all the possibility to make the network in safe. like i issue RLOCK and UNLOCK before issuing REPLACE or any other command that need to lock a record when it issued.What are the lists of the possibility why the tableupdate(.T.) could not commit successfully?

Use aerror(), as Armin mentions.

Common causes for not being able to save are:

Conflict update (another user edited the record in the meantime).

Trigger failed. This is often caused by a Referential Integrity rule.

Duplicate key (as defined by a primary or candidate index).

Violation of field-level or record-level rule.

Hilmar.

Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)