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REPLACE
Assign new values to field variables
------------------------------------------------------------------------------
Syntax
REPLACE <idField> WITH <exp>
[, <idField2> WITH <exp2>...]
[<scope>] [WHILE <lCondition>] [FOR <lCondition>]
Arguments
<idField> is the name of the field variable to be assigned a new
value. If <idField> is prefaced with an alias, the assignment takes
place in the designated work area.
WITH <exp> defines the value to assign to <idField>.
<scope> is the portion of the current database file to REPLACE. The
default is the current record, or NEXT 1. Specifying a condition
changes the default to ALL records in the current work area.
WHILE <lCondition> specifies the set of records meeting the
condition from the current record until the condition fails.
FOR <lCondition> specifies the conditional set of records to REPLACE
within the given scope.
Description
REPLACE is a database command that assigns new values to the contents of
one or more field variables in the current record in the specified work
areas. The target field variables can be character, date, logical,
memo, or numeric. REPLACE performs the same function as the assignment
operator (:=) except that it assumes that an unaliased reference is to a
field variable. This means that you can assign new values to field
variables using assignment statements provided that the field variable
references are prefaced with an alias, the FIELD alias, or declared
using the FIELD declaration statement.
The default scope of REPLACE is the current record unless a scope or
condition is specified. If a scope or condition is specified, the
replace operation is performed on each record matching the scope and/or
condition.
Warning! When you REPLACE a key field, the index is updated and the
relative position of the record pointer within the index is changed.
This means that REPLACEing a key field with a scope or a condition may
yield an erroneous result. To update a key field, SET ORDER TO 0 before
the REPLACE. This ensures that the record pointer moves sequentially in
natural order. All open indexes, however, are updated if the key field
is REPLACEd.
In a network environment, REPLACEing the current record requires an
RLOCK(). REPLACEing with a scope and/or condition requires an FLOCK()
or EXCLUSIVE USE of the current database file. If a field is being
REPLACEd in another work area by specifying its alias, that record must
also be locked with an RLOCK(). Refer to the "Network Programming"
chapter in the Programming and Utilities Guide for more information.
Examples
. This example shows a simple use of REPLACE:
USE Customer NEW
APPEND BLANK
USE Invoices NEW
APPEND BLANK
//
REPLACE Charges WITH Customer->Markup * Cost,;
Custid WITH Customer->Custid,;
Customer->TranDate WITH DATE()
. This example uses assignment statements in place of the
REPLACE command:
FIELD->Charges := Customer->Markup * FIELD->Cost
FIELD->Custid := Customer->Custid
Customer->TranDate := DATE()
Files Library is CLIPPER.LIB.
See Also:
COMMIT
FLOCK()
RLOCK()
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