Question 1,C10 marks total, 2 marks each) Short questions: in the fir a (True) i

Question

Question 1,C10 marks total, 2 marks each) Short questions: in the fir a (True) if it is completely correct, otherwise write choose the most correct answer , False). In the remaining () A database is a collection of related data. ) 2)A DBMS catalog stores the meta-data describing the structure of the 3)A DBMS is responsible for enforcing all the constraints of a data model. ( k in a three-schema architecture, change other schemas or applications is known as ) the capacity to change one schema a. Normal form b. Schema evolution c. Data independence d. Access path h R and S have the he (5) (A,B,C) is : The tuple relational calculus equivalent of R us, where both R and

Explanation / Answer

1. True

Database is a collection of related Data i.e., collection of related rows or records.

2. True

DBMS catalog stores metadata describing structure of database consists of database objects like tables, views, synonyms, indexes user groups etc.

3. False

Constraint specifications add additional restrictions on the contents of the table. They are automatically
enforced by the DBMS. DBMS is responsible for specification of integrity constrainsts like Entity integrity and referential integrity constraints.

But we cannot say DBMS is responsbile for enforcing all constraints of a data model. Based on the usablity and availability corresponding constraints will be used.

4.

Data Independence

Data independence is a concept which says changing one schema without changing another schema in a three schema architecture.

Explanation: Data Independence is divided as Physical Data Indepence and Logical Data Independence.

Physical Data independence: Changing physical level without effecting conceptual or external view of the data.

Logical Data Independence: Changing logical schema without causing change in external view(application Program).

5.

Option1 : {t|R(t) S(t)}

{t|R(t) S(t)} is equivalent to R U S in Relational Calculus

for every tuple in R i.e., R(t) v(or) and for every tuple in S i.e., S(t).

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