HP 3000 Manuals

QUERY/V Reference Manual

UNDO 

Restores the previous select file.

Syntax 

     UN[DO]

Discussion 

The UNDO command clears the last SUBSET retrieval and returns you to the
previous level of data retrieval.  Each group of retrieved entries is
stored in a temporary internal file known as a select file.  Entering the
UNDO command removes the last group of retrieved entries (select file)
and restores the previous group of retrieved entries as the current
select file.  The restored select file can be the result of a previous
SUBSET, FIND, or MULTIFIND command, but UNDO must follow a SUBSET
command.  After each SUBSET retrieval, QUERY prints the number of
qualified entries retrieved.

Examples 

Example 1 

     +-> >FIND ALL PERIODICAL.JOURNAL 
     |   USING SERIAL READ
     |   60 ENTRIES QUALIFIED
     |   >SUBSET PERIODICAL.JOURNAL = CALIFORNIA 
     |   30 ENTRIES QUALIFIED
     +-- >UNDO 

In this example, the previous 60 entries are in the current select file
again.

Example 2 

         >FIND ALL PERIODICAL.JOURNAL
         USING SERIAL READ
         60 ENTRIES QUALIFIED
     +-> >SUBSET PERIODICAL.JOURNAL = CALIFORNIA 
     |   30 ENTRIES QUALIFIED
     |   >SUBSET PERIODICAL.YEAR = 85 
     |   10 ENTRIES QUALIFIED
     +-- >UNDO 

In example 2, the previous 30 entries are in the current select file
again.

MPE/iX 5.0 Documentation