The information in this article applies to:
SUMMARY
The LOOKUP() function searches a database for the first occurrence of
a specified expression. If FoxPro finds the expression, it moves the
record pointer to the record that corresponds to the expression and
returns the contents of the specified field in the record. If no
matching record is found, the function returns the NULL string and
leaves the record pointer at the end of the file.
MORE INFORMATION
The syntax of the LOOKUP() function is as follows
where:
ExamplesThe following code searches the CUSTOMER.DBF file for the first occurrence of "Mark Cummings" in the CONTACT field. If LOOKUP() finds a matching record, it returns the contents of the COMPANY field.
The following code uses both the CUSTOMER.DBF and INVOICES.DBF files. LOOKUP() moves the record pointer through the CUSTOMER database until it finds a record that matches the current CNO field in INVOICES. LOOKUP() returns the contents of the COMPANY field in the CUSTOMER database.
If LOOKUP() includes the name of a compact index tag in the optional character expression <expC>, the search expression should match the index expression for the compact index tag. You can search the database for the contents of one field or a combination of fields by including the name of a compact index tag. The following code adds the CONTACT tag to the first example above:
When the LOOKUP() expression does not specify a tag and the database is indexed, FoxPro searches the primary index for the expression. If no index is available, the LOCATE command is used to search the database. NOTE: The Rushmore query-optimization system cannot optimize a LOOKUP() call. Additional query words: VFoxWin FoxDos FoxWin 2.50 2.50a 2.50b 2.60 2.60a lookup look up
Keywords : FxprgRushmore |
Last Reviewed: December 29, 1999 © 2000 Microsoft Corporation. All rights reserved. Terms of Use. |