You can check the validity of a single table either from Sybase Central or using a SQL statement. You must have either DBA or VALIDATE authority to validate a table.
Open the Tables folder.
Right-click the table and choose Validate from the popup menu.
A message box indicates whether the table is valid or not.
Execute the VALIDATE TABLE statement:
VALIDATE TABLE table-name;
If errors are reported, you can drop all of the indexes and keys on a table and recreate them. Any foreign keys to the table also need to be recreated. If you suspect a particular index, you can execute an ALTER INDEX ... REBUILD statement to rebuild the corrupted index. Another solution to errors reported by VALIDATE TABLE is to unload and reload your entire database. You should use the dbunload -u option so that it does not try to use a possibly corrupt index to order the data.
For more information about using the REBUILD clause of the ALTER INDEX statement, see ALTER INDEX statement.