Siemens V 4.0 Benutzerhandbuch

34

GINA V4.0 System Administrator Guide – September 2000

Customizing the database layout

The description file that is called using the

 -r

option, the so-called pfx file, handles the

specification of class-wide attribute names.

The attribute names used for the mapping to the database consist of the following compo-
nents:

classPrefix_attributCounter_extension

classPrefix

is the part of the field name that is common to all fields in a class. Neither does
inheritance change it, i.e. it has the same value in the subclass as in the superclass.
It can be specified by the user with the help of the

specified below.

When using identical views, this prefix is used to generate the attribute names of
both the table and also the view belonging to the class.

attributCounter

and

 extension

are always created by

mgen2

.

The description file consists of formatted lines with the following line format.

classname prefix

Classname

represents a valid C++ identifier.

prefix

represents a valid SQL identifier. The prefix entries must differ for all classes and
can be a maximum of 6 characters in length.

Please note that all entries in the description file are case-sensitive.

If no prefix is found for a specific class, it is automatically generated by the

 mgen2

gener-

ator. The created prefixes have the following format:

X

dddd

or

 X

ddddd

with

d=0,1,2,..,9

The generation starts at

 X

dddd=X1024

or

X

mmmm

, where

 mmmm

represents the highest

value for

dddd+1

found in the description file. That means that if

X10200

was found in the

description file, the generation starts at

 X10201

.

Once prefixes have been specified by the

 mgen2

for all classes, both those found in the

description file and the newly generated prefixes are output to the specified description file.
The old version of the pfx file is first backed up to a file with the extension

.bak

. An empty

or non-existent description file can be specified for use in the creation of the first description
file.