Data definition language

1. A language enabling the structure and instances of a database to be defined in a human-, and machine-readable form.

SQL contains DDL commands that can be used either interactively, or within programming language source code, to define databases and their components, e.g. CREATE and DROP.

2. A specification language for databases, based on the entity-relationship model. It is used in the Eli compiler-compiler to manage type definitions.

["DDL Reference Manual", ECE Dept U Colorado, 1991].