Database Management System MCQs

A primary key is combined with a foreign key creates

The entity set person is classified as student and employee. This process is called _________

Which relationship is used to represent a specialization entity?

The refinement from an initial entity set into successive levels of entity subgroupings represents a ________ design process in which distinctions are made explicit.

There are similarities between the instructor entity set and the secretary entity set in the sense that they have several attributes that are conceptually the same across the two entity sets: namely, the identifier, name, and salary attributes. This process is called

If an entity set is a lower-level entity set in more than one ISA relationship, then the entity set has

A _____________ constraint requires that an entity belong to no more than one lower-level entity set.

The completeness constraint may be one of the following: Total generalization or specialization, Partial generalization or specialization. Which is the default?

Functional dependencies are a generalization of

Which of the following is another name for a weak entity?

Which is the main relation which is used in the university database which is referenced by all other relation of the university?

The department relation has the an entry budget whose type has to be replaced by

In the course relation, the title field should throw an error in case of any missing title. The command to be added in title is

In the above DDL command the foreign key entries are got by using the keyword

Identify the error in the section relation

The following entry is given in to the instructor relation . (100202,Drake,Biology,30000)

In the section relation which of the following is used as a foreign key?

In order to include an attribute Name to the teaches relation which of the following command is used?

To replace the relation section with some other relation the initial step to be carried out is

Which of the following command is used to display the departments of the instructor relation?

How can we select the elements which have common Dept_name in both the relation ?

Select distinct Dept_name from instructor ; How many row(s) are displayed ?

If a person all the people in Music department gets fired which of the following has to be performed on the instructor relation ?

Which function is used to find the count of distinct departments?

Which function is used to identify the title with Least scope?

A domain is ______ if elements of the domain are considered to be indivisible units.

Identify the composite attributes

Consider the relation given below and ind the maximum normal form applicable to them i. R(A, B) WITH productions { A --> B } ii. R(A, B) WITH productions { B --> A } iii. R(A, B) WITH productions {A —> B, B --> A } iv. R(A, B, C) WITH productions {A -->B, B --> A, AB --> C }

Which one is based on multi-valued dependency:

If a relation is in BCNF, then it is also in

If an attribute of a composite key is dependent on an attribute of the other composite key, a normalization called _____ is needed.

The term for information that describes what type of data is available in a database is:

A data type that creates unique numbers for key columns in Microsoft Access is:

A dependency exist between two columns when

In the __________ normal form, a composite attribute is converted to individual attributes.

A table on the many side of a one to many or many to many relationship must:

Tables in second normal form (2NF):

Which-one ofthe following statements about normal forms is FALSE?

Functional Dependencies are the types of constraints that are based on______

Which is a bottom-up approach to database design that design by examining the relationship between attributes:

Which forms has a relation that possesses data about an individual entity:

Which forms are based on the concept of functional dependency:

We can use the following three rules to find logically implied functional dependencies. This collection of rules is called

Which of the following is not Armstrong’s Axiom?

The relation employee(ID,name,street,Credit,street,city,salary) is decomposed into employee1 (ID, name) employee2 (name, street, city, salary)

Inst_dept (ID, name, salary, dept name, building, budget) is decomposed into instructor (ID, name, dept name, salary) department (dept name, building, budget)

There are two functional dependencies with the same set of attributes on the left side of the arrow: A->BC A->B This can be combined as

Suppose we wish to find the ID’s of the employees that are managed by people who are managed by the employee with ID 123. Here are two possible queries: I.SELECT ee.empID FROM Emps ee, Emps ff WHERE ee.mgrID = ff.empID AND ff.mgrID = 123; II.SELECT empID FROM Emps WHERE mgrID IN (SELECT empID FROM Emps WHERE mgrID = 123);

Suppose relation R(A,B) currently has tuples {(1,2), (1,3), (3,4)} and relation S(B,C) currently has {(2,5), (4,6), (7,8)}. Then the number of tuples in the result of the SQL query: <i>SELECT * FROM R NATURAL OUTER JOIN S; </i>IS:

Suppose now that R(A,B) and S(A,B) are two relations with r and s tuples, respectively (again, not necessarily distinct). If m is the number of (not necessarily distinct) tuples in the result of the SQL query: R intersect S;