Question

Differentiate between:-
1. char and varchar data type
2. DDL and DML

Answer 1

CHAR is fixed length and VARCHAR is variable length. ... Because varchar is a variable-length data type, the storage size of the varchar value is the actual length of the data entered, not the maximum size for this column. You can use char when the data entries in a column are expected to be the same size.

The basic difference between DDL and DML is that DDL (Data Definition Language) is used to Specify the database schema database structure. On the other hand, DML (Data Manipulation Language) is used to access, modify or retrieve the data from the database.

Answer 2

VARCHAR is variable-length.

CHAR is fixed length.

If your content is a fixed size, you'll get better performance with CHAR.



DDL is Data Definition Language : it is used to define data structures.

For example, with SQL, it would be instructions such as create table, alter table, ...


DML is Data Manipulation Language : it is used to manipulate data itself.