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ORDSCOPE()
Set or clear the boundaries for scoping key values in the controlling order
------------------------------------------------------------------------------
Syntax
ORDSCOPE(<nScope>, [<expNewValue>]) --> uCurrentValue
Arguments
<nScope> is a number specifying the top (TOPSCOPE) or bottom
(BOTTOMSCOPE) boundary.
Note: To use the TOPSCOPE and BOTTOMSCOPE constants, you must
include (#include) the Ord.ch header file in your application.
<expNewValue> is the top or bottom range of key values that will be
included in the controlling order's current scope. <expNewValue> can be
an expression that matches the data type of the key expression in the
controlling order or a code block that returns the correct data type.
Omitting <expNewValue> or specifying it as NIL has the special effect of
resetting the specified scope to its original default. The default top
range is the first logical record in the controlling order, and the
default bottom range is the last logical record.
Returns
If <expNewValue> is not specified, ORDSCOPE() returns and clears the
current setting. If <expNewValue> is specified, the function sets it
and the previous setting is returned.
Description
The range of values specified using ORDSCOPE() is inclusive. In other
words, the keys included in the scope will be greater than or equal to
the top boundary and less than or equal to the bottom boundary.
Note: To return current settings without changing them, call the
DBORDERINFO() function using the DBOI_SCOPETOP and DBOI_SCOPEBOTTOM
constants.
Examples
. This example illustrates using ORDSCOPE() to set various
scoping limitations on an order:
USE Friends
SET INDEX TO Age
// Make 25 the lowest age in range
ORDSCOPE(TOPSCOPE, 25)
// Make 30 the highest age in range
ORDSCOPE(BOTTOMSCOPE, 30)
LIST Age // Shows records with
// 25 <= Age <= 30
// Change highest age to 35
ORDSCOPE(BOTTOMSCOPE, 35)
LIST Age // Shows records with
// 25 <= Age <= 35
// Reset top boundary
ORDSCOPE(TOPSCOPE, NIL)
LIST Age // Shows records with
// Age <= 35
// Reset bottom boundary
ORDSCOPE(BOTTOMSCOPE, NIL)
LIST Age // Shows all records
Files Library is CLIPPER.LIB, header file is Ord.ch.
See Also:
SET SCOPE
SET SCOPEBOTTOM
SET SCOPETOP
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