HP 3000 Manuals

HP Transact Reference Manual

Match Register 

The match register contains the selection criteria for data retrieval
operations.  It holds a set of data item names and selection criteria for
each data item name in the set.  The match criteria determine which
records are selected for retrieval from a data set or file.  Only those
records that meet the criteria are retrieved.

To use the match criteria, the match items must be in the list register,
and they also must be retrieved by the data management statement that
uses the match criteria.  Therefore, you must add match items to the
match register, add each data item to the list register, and include each
data item in a LIST= option of the data management statement.  If a match
item is not specified in the LIST= option, or the LIST= option is omitted
and the match item is not in the list register, the data management
statement ignores the match criteria associated with that data item.

You can specify as many match criteria as you want.  Also, you can assign
different criteria to the same data item or to different data items, or
specify the same criteria for different data items.  By default, a
Boolean AND connects selection criteria gathered from different
PROMPT(MATCH) or DATA(MATCH) statements.  A Boolean AND also connects
selection criteria from multiple SET(MATCH) statements unless the
statements use the same data item name and specify equality as the
connector; such statements are joined by a Boolean OR.

For example, consider the following match register that contains four
separate match criteria:


            

Entries in the match register can be cleared or selectively deleted by
using the RESET verb with the MATCH option.  Users can also override the
specific defaults with their responses to a PROMPT(MATCH) or a
DATA(MATCH) prompt.  See "Responding to a MATCH Prompt" in Chapter 5.

MPE/iX 5.0 Documentation