FREE TABLE Command Removes Table from Corrupted Database

MORE INFORMATION

If FREE TABLE is used to remove a table from a database that is not corrupted, the Table Designer window still displays the table. However, the table is no longer really part of the database, and issuing the VALIDATE DATABASE command causes the following error message to be displayed: Also, attempting to browse or modify the table causes the error message to be displayed: Answering Yes to this question recreates the back link of the table to the database and issuing the VALIDATE DATABASE command returns the message "Database container is valid". The table is now part of the database again.

Example Usage of the FREE TABLE Command

CAUTION: Performing this example will corrupt the TESTDATA.DBC database in the SAMPLE subdirectory.

1. First corrupt a database by running the following:

         SET DEFAULT TO c:\vfp\samples\data
         USE testdata.dbc
         GO TOP
         DELETE            && Delete one record of the .DBC.
         USE               && Now TESTDATA cannot be opened as a database
   							

2. Run the following program which has an on error routine to trap for a damaged database. If this program is run without the error routine, the message "Testdata.DBC is not a database" will be returned.

         SET PROCEDURE TO freetabl      && FREETABL is the name of the program
   
         ON ERROR DO errhand WITH ERROR()
         * The next line should cause an error because the first record
         * was deleted from TESTDATA.DBC
   
         OPEN DATA testdata
         USE customer
         USE products IN 0
         USE orders IN 0
         USE orditems IN 0
         USE employee IN 0
   
         ON ERROR  && restore system error handler
   
         PROCEDURE errhand
           PARAMETER merror
           WAIT WINDOW STR(merror)
           IF merror=1552
             FREE TABLE customer      && Allows the tables to be opened
             FREE TABLE orders        && by freeing them from the corrupted
             FREE TABLE products      && DATABASE
             FREE TABLE orditems
             FREE TABLE employee
           ENDIF