iX V6.5 (30391-90011)

130 Chapter4

Using the Database

Obtaining Database Structure Information

set is a detail set, the information includes the master data set number of the related

master data set, the detail search item number and sort item number for each path.

• Determine the key item number of a master data set or the search item number for the

primary path of the detail and the data set number of the related master. In either case,

if the search item is inaccessible to the current user, no information is returned.

Special Uses of DBINFO

If the application program uses data items and data set numbers when calling the other

TurboIMAGE/XL procedures, it is good practice to determine these numbers by calling

DBINFO at the beginning of the program to set up the numbers. It is not practical to code

the numbers into the program because a change to the database structure might require

extensive changes to the application programs. Likewise, it is inefﬁcient and time

consuming to call DBINFO throughout the program to determine these numbers. Many

application programmers prefer the convenience and ﬂexibility of using the data item and

data set names in procedure calls.

DBINFO is useful when writing general inquiry applications similar to the QUERY/3000

database inquiry facility. DBINFO can also be used to obtain information regarding the

logging facility, dynamic transactions, third-party indexing, and the critical item update

(CIUPDATE) option settings for a database and the current process. In relation to Native

Language Support (NLS), DBINFO can be used to get the MPE/iX numeric code that deﬁnes

the native language supported by the database. (Refer to "Database Description

Language" and "Schema Structure" in chapter 3.)

Checking Subsystem Flag

A subsystem ﬂag can be set with the DBUTIL >>SET command. This ﬂag indicates whether

subsystems, including user programs, can access the TurboIMAGE/XL database and, if

access is allowed, whether it is read only or both read and write. Because the ﬂag does not

actually allow or prevent access, the subsystem or user program must include a call to

DBINFO to test this ﬂag. QUERY/3000 is the primary subsystem which uses the subsystem

ﬂag.