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MEMOSETSUPER()
Set an RDD inheritance chain for the DBFMEMO database driver
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Syntax
MEMOSETSUPER([<cSuperRDD>]) --> cOldSuperName
Arguments
<cSuperRDD> is a character string representing the name of the RDD
from which DBFMEMO will inherit.
Returns
MEMOSETSUPER() always returns NIL.
Description
The DBFMEMO driver is only capable of handling commands and functions
that relate to memo fields. Therefore, it must inherit the non-memo
database characteristics (such as SKIP, REPLACE, SEEK, etc.) from a
"super" driver (such as DBFNTX).
For example, the DBFCDX RDD is nothing more than the DBFMEMO RDD
hardwired to inherit database characteristics from the _DBFCDX RDD.
That is, when you use the DBFCDX RDD, you are using the DBFMEMO driver
to handle the memo field operations and you are using the _DBFCDX driver
to handle the other database and index operations as the "super" driver.
At times, you may want to use a database driver such as DBFNTX instead
of DBFCDX but, at the same time, have the efficient and enhanced memo
field capabilities of the DBFMEMO RDD instead of the DBT memo file
format. In order to do this, you would use MEMOSETSUPER().
Warning! The MEMOSETSUPER() function can only set one inheritance
chain per application instance. That is, once you have set
MEMOSETSUPER() in an application, MEMOSETSUPER() cannot be changed.
Doing so will have unpredictable results.
Examples
. This example uses MEMOSETSUPER() to create a database (.dbf)
file with an .fpt/.dbv memo field:
REQUEST DBFMEMO
// Set the default to DBFMEMO
RDDSETDEFAULT( "DBFMEMO" )
// Make DBFMEMO inherit from DBFNTX
MEMOSETSUPER( "DBFNTX" )
// Create a DBF with an FPT/DBV not DBT
dbCreate( "test.dbf", {{"notes", "M", 10, 0}} )
// Open DBF with FPT/DBV
// Indexes created would be NTX if created
USE test NEW
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