When you define a DB2® database, you name an eventual collection of tables, associated indexes, and the table spaces in which they are to reside.

When you decide whether to define a new database for a new set of objects or use an existing database, consider the following facts:

• You can start and stop an entire database as a unit. You can display the status of all objects in the database by using a single command that names only the database. Therefore, place a set of related tables into the same database. (The same database holds all indexes on those tables.)
• If you want to improve concurrency and memory use, keep the number of tables in a single database relatively small (maximum of 20 tables). For example, with fewer tables, DB2 performs a reorganization in a shorter length of time.
• Having separate databases allows data definitions to run concurrently and also uses less space for control blocks.

To create a database, use the CREATE DATABASE statement. A name for a database is an unqualified identifier of up to eight characters. A DB2 database name must not be the same as the name of any other DB2 database.

In new-function mode, if you do not specify the IN clause on the CREATE TABLE statement, DB2 implicitly creates a database. The following list shows the names for an implicit database:

DSN00001, DSN00002, DSN00003, ..., DSN10000

CREATE DATABASE MYDB
  STOGROUP MYSTOGRP
  BUFFERPOOL BP8K4
  INDEXBP BP4;