Data Definition Language

DDL is the notation used for creating the database schema

Example:

CREATE TABLE Customers (
    ID char(5),
    name varchar(20),
    city varchar(20),
    balance numeric(8,2)
);

The Data Dictionary

• The DDL compiler stores a set of table templates in a data dictionary
• The data dictionary contains metadata including:
  • Database schemas
  • Integrity constraints, notably the primary key
  • Authorisation details