<P> The concept of the data definition language and its name was first introduced in relation to the Codasyl database model, where the schema of the database was written in a language syntax describing the records, fields, and sets of the user data model . Later it was used to refer to a subset of Structured Query Language (SQL) for declaring tables, columns, data types and constraints . SQL - 92 introduced a schema manipulation language and schema information tables to query schemas . These information tables were specified as SQL / Schemata in SQL: 2003 . The term DDL is also used in a generic sense to refer to any formal language for describing data or information structures . </P> <P> Many data description languages use a declarative syntax to define columns and data types . Structured query language (e.g., 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 . These statements can be freely mixed with other SQL statements, making the DDL not a separate language . </P> <P> The create command is used to establish a new database, table, index, or stored procedure . </P> <P> The CREATE statement in SQL creates a component in a relational database management system (RDBMS). In the SQL 1992 specification, the types of components that can be created are schemas, tables, views, domains, character sets, collations, translations, and assertions . Many implementations extend the syntax to allow creation of additional elements, such as indexes and user profiles . 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 . </P>

Which is not part of data definition language