12th CMS || Database Concept || Questions Lists!

 Q1) What is a Database System? What it’s need?

Q2) Define the following terms:-

a) Data    b) Information     c) DBMS   d) RDBMS

Q3) How many types of users works on database system?

Q4) What are various levels of data abstraction in database system?

Q5) How many different types of data independence?

Q6) What are various supported data models of database system?

Q7) Define the following relational model terminology:-

a)Tuple   b)Attribute  c)Degree  d)Cardinality e)Relation   f)Field   g)Table  h)File

Q8) Explain the following types of key with example:-

a)Primary Key b)Candidate Key c)Alternate Key d)Foreign Key

Q9) What do you mean by DBA? Explain the role of DBA.

Q10) What do you mean by SQL? Categorised the following SQL Condition.

Q11) Define the terms:

i. Database Abstraction

Ans: Database system provides the users only that much information that is required

by them, and hides certain details like, how the data is stored and maintained in database at hardware level. This concept/process is Database abstraction.

ii. Data inconsistency

Ans: When two or more entries about the same data do not agree i.e. when one of

them stores the updated information and the other does not, it results in data inconsistency in the database.

iii. Conceptual level of database implementation/abstraction

Ans: It describes what data are actually stored in the database. It also describes the relationships existing among data. At this level the database is described logically in terms of simple data-structures.

iv. Primary Key

Ans : It is a key/attribute or a set of attributes that can uniquely identify tuples within the relation.

v. Candidate Key

Ans : All attributes combinations inside a relation that can serve as primary key are candidate key as they are candidates for being as a primary key or a part of it.

vi. Relational Algebra

Ans : It is the collections of rules and operations on relations(tables). The various operations 

are selection, projection, Cartesian product, union, set difference and intersection, and joining of relations.

vii. Domain

Ans : it is the pool or collection of data from which the actual values appearing in a given column are drawn.

Q12) What is relation? What is the difference between a tuple and an attribute?

Q13) Define the following terminologies used in Relational Algebra:

(i) selection (ii) projection (iii) union (iv) Cartesian product

Q14) What are DDL and DML?

Q15) Differentiate between primary key and candidate key in a relation?

Q16) What do you understand by the terms Cardinality and Degree of a relation in relational database?

Q17) Differentiate between DDL and DML. Mention the 2 commands for each category.

Q18) What is a Constrains? Explain the different types of constraints.