Data Definition Language(DDL) Specification notation for defining the database schema Example: create table instructor ID char(5), name varchar(20), dept name varchar(20), salary numeric(8,2)) DDL compiler generates a set of table templates stored in a data dictionary Data dictionary contains metadata (i.e.,data about data) Database schema Integrity constraints Primary key (ID uniquely identifies instructors) Authorization Who can access what Database System Concepts-6th Edition 1.13 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 1.13 ©Silberschatz, Korth and Sudarshan th Edition Data Definition Language (DDL) Specification notation for defining the database schema Example: create table instructor ( ID char(5), name varchar(20), dept_name varchar(20), salary numeric(8,2)) DDL compiler generates a set of table templates stored in a data dictionary Data dictionary contains metadata (i.e., data about data) Database schema Integrity constraints  Primary key (ID uniquely identifies instructors) Authorization  Who can access what