IBM 000-8697 Manual Do Utilizador

IBM Informix OnLine Database Server Administrator’s Guide

Each database tblspace entry includes four components:

■

Database name

■

Database owner

■

Date and time the database was created

■

The tblspace number of the systables system catalog table for this
database

The database tblspace includes a unique index on the database name to
ensure that every database is uniquely named. For any database, the
systables

table describes each permanent table in the database. Therefore, the

database tblspace only points to the detailed database information located
elsewhere. When the root dbspace is initialized, the database tblspace first
extent is allocated. The initial extent size and the next extent size for the
database tblspace are four pages. You cannot modify these values.

After the root dbspace exists, users can create a database. The

SQL

statement

CREATE DATABASE

allows users to specify the dbspace where the database is

to reside. This dbspace is the location for the database system catalog tables
and all data and corresponding index information. (Blob data can be stored
in a separate blobspace.)

By default, the database is created in the root dbspace. Users can place the
database in another dbspace by specifying the dbspace name in the

CREATE

DATABASE

 statement.

The paragraphs that follow describe the major events that occur on disk
when OnLine adds a new database.