Data Definition Language (DDL) & Data Manipulation Language (DML), What is Metadata?

Data Definition Language (DDL) & Data Manipulation Language (DML), What is Metadata?

Data Definition Language (DDL)
It is the specification notation for defining the database schema
E.g.
create table account (
account-number char(10),
balance integer)
DDL compiler generates a set of tables stored in a data dictionary


Data dictionary contains metadata (i.e data about the data)
1.)database schema
2.)Data storage and definition language

• language in which the storage structure and access methods used by the database system are specified
• Usually an extension of the data definition language
  

Data Manipulation Language (DML)

It is the Language for accessing and manipulating the data organized by the appropriate data model

DML also known as query language

Two classes of languages

Procedural – user specifies what data is required and how to get those data

Non-procedural – user specifies what data is required without

specifying how to get those data

SQL is the most widely used query language