ALLBASE/SQL Reference Manual (36216-90216)

Chapter 1 47
Introduction
ALLBASE/SQL Databases
A DBEnvironment, illustrated in Figure 1-4., houses the DBEFiles for one or more
ALLBASE/SQL databases, plus the following, which contain information for
all databases
in the DBEnvironment:
•ADBECon file. This file contains information about the DBEnvironment
configuration, such as the size of various buffers and other startup parameters. The
name of the DBECon file is the same as the name of the DBEnvironment.
•Asystem catalog. The system catalog is a collection of tables and views that contain
data describing DBEnvironment structure and activity. The parts of the system catalog
necessary for DBEnvironment startup reside in a DBEFile known by default as
DBEFile0. All system catalog DBEFiles are associated with a DBEFileSet called
SYSTEM.
• One or two log files. A log file contains a log of DBEnvironment changes.
ALLBASE/SQL uses log files to undo (roll back) or redo (roll forward) changes made
in the DBEnvironment. The log files are known by default as DBELog1 and
DBELog2.
Figure 1-4. Elements of an ALLBASE/SQL DBEnvironment
Most database users need not be concerned with the physical aspects of ALLBASE/SQL
databases beyond knowing which DBEnvironment contains the databases they want to
access.