Difference between revisions of "REFERENCES()"

Latest revision as of 09:00, 28 October 2019

Purpose

Function to perform a cross-table lookup for a specified key expression

Syntax

REFERENCES(<key expression>, <workarea | alias> [,<tag name>])

See Also

ALIAS(), INDEX, KEY(), KEYMATCH(), LOOKUP(), RLOOKUP(), SEEK, SEEK(), SET RELATION, TAG(), TAGCOUNT(), TAGNO()

Description

The REFERENCES() function looks up the specified <key expression> in the master tag index of the specified <workarea | alias>. The <workarea | alias> is the workarea or alias name of an open table. To search in a tag index which is not the current master index, the optional <tag name> parameter can be used. The tag name must be specified as a string.

If the target table is not open, but is in the active database, it can be specified as a string: <table name>. The tag name <tag name> string must also be specified.

The REFERENCES() function returns True (.T.) or False (.F.), depending on the success of the lookup operation.

Please see the RLOOKUP() function for cross-table lookups using single indexes (.ndx).

Example

open database southwind
use customers order customerid in 2
use orders in 1
? references(customerid,2)
.T.
? references(customerid,customers)
.T.
 
select customers
set order to address
select orders
// Specify the index tag string to search in non-master index
? references(customerid,2,"customerid")
.T.
? references(customerid,customers,"customerid")
.T.
 
select customers
use
select orders
// customers table is not currently open
? references(customerid,"customers","customerid")
.T.