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OPEN_DBF() Opens a DBF file and all its NTX files
Description:
OPEN_DBF() uses a database dictionary to open a specified database and
all its associated index files.
Syntax:
OPEN_DBF( <expC> )
Pass:
<expC> = Name of database to open. i.e. "MYFILE"
Return:
<expL> = .T. if successful, otherwise .F.
Notes:
You must have properly setup the database and index dictionary.
Sample database and index dictionaries have been provided with this
library (DBF_DICT.DBF and NTX_DICT.DBF). Please study these examples
to see how to properly setup a database/index dictionary.
*** WARNING!! EXTREMELY IMPORTANT *** OPEN_DBF() requires that you
do not open any database file in work area 10 (J). If you do, you will
experience unpredictable results!
Example:
OPEN_DBF( "CLIENTS" )
.
.
.
Usage:
OPEN_DBF() is primarily used to allow several different database
applications to access common databases and maintain common index
files without having to re-compile and link each application.
In other words, the database structures and index keys are maintained
outside of **ALL** applications and thus can be used by all
applications.
Example: Let's assume that you are writing a program that maintains an
inventory database and you main file is called INVENT.DBF. You have
an index called INV_NMBR.NTX with a key of "PROD_CODE+WHSE".
Let's further assume that a co-worker of yours is writing a program
that produces a listing of inventory based on its sales volume.
He/She needs an index file called INV_VOL.NTX with a key of
"TOT_SALES+PROC_CODE".
All that needs to take place so that both index files are maintained
is... the index file and its key are added to the index dictionary.
In this fashion your inventory maintenance program will open and
maintain the index file needed by your co-worker and vice-versa.
See Also:
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