Difference between revisions of "KEYLOOKUP()"
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==Syntax== | ==Syntax== | ||
− | KEYLOOKUP(<workarea | alias>, <"tagname">, < | + | KEYLOOKUP(<workarea | alias | table>, <"tagname">, <keyExpr>, <valueExpr>) |
==See Also== | ==See Also== | ||
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==Description== | ==Description== | ||
− | The KEYLOOKUP() function looks up the specified index < | + | The KEYLOOKUP() function looks up the specified index <keyExpr> in the index <tagname> of the specified <workarea | alias | table>. The KEYLOOKUP() function then evaluates the expression <valueExpr>, and returns the value of the <valueExpr> if the <key expression> is found. The KEYLOOKUP() function returns a null string if the <key expression> is not found. |
− | The current record position in the specified <workarea | alias> cursor is not moved so this function can also safely be used in SQL queries. If the specified < | + | The current record position in the specified <workarea | alias | table> cursor is not moved so this function can also safely be used in SQL queries. |
+ | |||
+ | If the specified <table> is not already open then Lianja will open the table automatically. | ||
+ | |||
+ | This function can be used to dynamically lookup foreign key values in target tables. | ||
+ | |||
+ | It can also be used to lookup NoSQL key/value pairs. | ||
==Example== | ==Example== |
Revision as of 07:59, 8 December 2012
Contents
Purpose
Function to perform a cross-table lookup
Syntax
KEYLOOKUP(<workarea | alias | table>, <"tagname">, <keyExpr>, <valueExpr>)
See Also
LOOKUP(), RLOOKUP(), SEEK(), SET RELATION
Description
The KEYLOOKUP() function looks up the specified index <keyExpr> in the index <tagname> of the specified <workarea | alias | table>. The KEYLOOKUP() function then evaluates the expression <valueExpr>, and returns the value of the <valueExpr> if the <key expression> is found. The KEYLOOKUP() function returns a null string if the <key expression> is not found.
The current record position in the specified <workarea | alias | table> cursor is not moved so this function can also safely be used in SQL queries.
If the specified