Additional information for DB2 SQL

These topics contain additional information for DB2® SQL.

Limits in DB2 for z/OS
DB2 for z/OS® has system limits, object and SQL limits, length limits for identifiers and strings, and limits for certain data type values.
Reserved schema names and reserved words
Restrictions exist on the use of certain names that are used by DB2. In some cases, names are reserved and cannot be used by application programs. In other cases, certain names are not recommended for use by application programs though not prevented by the database manager.
Characteristics of SQL statements in DB2 for z/OS
DB2 allows specific actions on each SQL statement, and only certain SQL statements are allowed in external routines and SQL procedures.
SQL control statements for external SQL procedures
SQL control statements for external SQL procedures can be used only with SQL procedures that are created with the FENCED or EXTERNAL clause. SQL control statements provide the capability to control the logic flow, declare and set variables, and handle warnings and exceptions. Some SQL control statements include other nested SQL statements.
SQL communication area (SQLCA)
An SQLCA is a structure or collection of variables that is updated after each SQL statement executes. An application program that contains executable SQL statements must provide exactly one SQLCA, with a few exceptions.
SQL descriptor area (SQLDA)
An SQLDA is a collection of variables that is required for execution of the SQL DESCRIBE statement, and can be optionally used by the PREPARE, OPEN, FETCH, EXECUTE, and CALL statements. An SQLDA can be used in a DESCRIBE or PREPARE INTO statement, modified with the addresses of host variables, and then reused in a FETCH statement.
DB2 directory tables
DB2 for z/OS maintains a set of tables (in database DSNDB01) called the DB2 directory. Authorized users can query the directory; however, it is primarily intended for use by DB2 and is therefore subject to change.
DB2 XML schema repository tables
The DB2 for z/OS XML schema repository (XSR) is a set of DB2 tables where you can store XML schemas.
Sample user-defined functions
Some sample user-defined functions are provided with DB2. You can use the functions in your applications just as you would use other user-defined functions, or as examples to help you define your own user-defined functions.

Parent topic: SQL: The language of DB2