Diploma in Computer Science & Engineering
Subject: DBMS
DBMS - GA 2
Max.Marks:05
Q1) Explain the Normalization in full detail.
Ans- Normalization is a database design technique that reduces data
redundancy and eliminates undesirable characteristics like Insertion,
Update and Deletion Anomalies. Normalization rules divides larger
tables into smaller tables and links them using relationships. The
purpose of Normalisation in SQL is to eliminate redundant (repetitive)
data and ensure data is stored logically.
Q2) Write the Characteristics of SQL.
Ans- 1. SQL is oriented specifically around relational databases.
2. SQL commands can operate on several groups of tables as single
objects. It also processes any quantity of information, retrieved from
these tables as a single unit.
3. SQL allows the use of temporary tables. Temporary tables are used
for storing intermediate results. They are useful only for the duration
the program is in execution, and get deleted when the program
terminates.
4. SQL is well suited to a client-server environment, where the DBMS
resides on a server and services the client’s requests.
5. SQL can execute the queries against the database.
6. SQL provides flexible transaction management. A transaction is a
group of SQL statements that succeed or fail as a group. That is if any
one of the SQL statements fails, the whole transaction is aborted.
7.SQL allows users to create domains as objects in a schema. The users
can then declare table columns to be of domains rather than data
types.
8. SQL allows one to specify constraints. Constraints are rules for
restricting the values that can be placed in a table column.
9. Privileges can be granted or denied using SQL commands. Privileges
are the rights to perform actions on database objects.
10. SQL used to create a view, stored procedure, function in a database
Q3) Write the storage organizations for relations.
Ans- Storage organise means how data is stored in database.in data
base data is stored inform of table,which is also known as relation.some
organisation are known as
*table
*row
*tuple
*degree
*cardinality
Q4) Write the difference between relational algebra &
relational calculus.
Ans- Difference between Relational Algebra and Relational Calculus
Relational Algebra:
Relational Algebra is a procedural language. In Relational Algebra, The
order is specified in which the operations have to be performed. In
Relational Algebra, frameworks are created to implement the queries.
The basic operation included in relational algebra are:
1. Select (σ)
2. Project (Π)
3. Union (U)
4. Set Difference (-)
5. Cartesian product (X)
6. Rename (ρ)
Q5) Write the Types of SQL commands in detail.
Ans- Relational Calculus:
Relational Calculus is the formal query language. It is also known as
Declarative language. In Relational Calculus, the order is not specified in
which the operation has to be performed. Relational Calculus means
what result we have to obtain.
Relational Calculus has two variations:
Tuple Relational Calculus (TRC)
Domain Relational Calculus (DRC)
Relational Calculus is denoted as:
{ t | P(t) } Where,
t: the set of tuples
p: is the condition which is true for the given set of tuples.
