Create table BOOK
BOOK ID Char (4)
Bname Varchar (15)
Author Varchar (20)
Price Decimal
a) Identify the primary key of the Book Table, also mention the suitable reason for
choosing it as a Primary Key
b) Differentiate between
i. char and varchar data type
ii. DDL and DML
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Answer:
a) A primary key identifies all table records uniquely. It can be the ID columns in general cases. Therefore, we can select the BOOK ID column as a primary key in this case.
b) Char data type has fixed length, and Varchar data type has a variable length, which means that the length of data is not fixed.
c) DDL is Data Definition Language whereas DML is Data Manipulation Language. The distinction between the two is that DDL consists of commands which let us define data. On the other hand, DML lets us manipulate data by using insert, delete and such commands.
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