A schema is a collection of named objects (tables and views, for example). A schema provides a logical classification of objects in the database.
A schema is created implicitly when you create a table, a view or any other named object. Or, you can create it explicitly using the CREATE SCHEMA statement.
When you create a named object, you can qualify (associate) its name with the name of the particular schema. Named objects have two-part names, where the first part of the name is the schema name to which the object is assigned. If you do not specify a schema name, the object is assigned to the default schema. (The name of the default schema is the authorization ID of the user executing the statement.)
For interactive SQL, the method used to execute the examples in this book, the authorization ID is the user ID specified with the CONNECT statement. For example, if the name of a table is STAFF, and the user ID specified is USERXYZ, then the qualified table name is USERXYZ.STAFF. See Connecting to a Database for details on the CONNECT statement.
Some schema names are reserved. For example, built-in functions are in the SYSIBM schema while the preinstalled user-defined functions belong to the SYSFUN schema. Refer to the SQL Reference for details on the CREATE SCHEMA statement.