Data definition language

[1] Later it was used to refer to a subset of Structured Query Language (SQL) for declaring tables, columns, data types and constraints.

The term DDL is also used in a generic sense to refer to any formal language for describing data or information structures.

Structured Query Language (SQL), however, uses a collection of imperative verbs whose effect is to modify the schema of the database by adding, changing, or deleting definitions of tables or other elements.

In the SQL 1992 specification, the types of components that can be created are schemas, tables, views, domains, character sets, collations, translations, and assertions.

Some systems, such as PostgreSQL and SQL Server, allow CREATE, and other DDL commands, inside a database transaction and thus they may be rolled back.

An ALTER statement in SQL changes the properties of an object inside of a relational database management system (RDBMS).