Computer Database Management (DBMS) MCQ's




Question 1 :
If the attribute of relation schema R is not a member of some candidate key then this type of attribute is classified as

  1. nonprime attribute
  2. prime attribute
  3. atomic attribute
  4. candidate attribute
  

Question 2 :
__________is an example of a multi-valued attribute .

  1. Adhar card number
  2. PAN number
  3. Roll number
  4. Phone Number
  

Question 3 :
Select ________ project_name from project; replace _______with suitable value to print the unique values of the column ?

  1. All
  2. From
  3. Distinct
  4. Name
  

Question 4 :
Which one statement about keys is correct out of the following?

  1. Candidate key is a subset of super key
  2. Super key is a subset of candidate key
  3. Candidate key is a subset of primary key
  4. A relation can have only one candidate key
  

Question 5 :
A relation is in this form if it is in BCNF and has no multivalued dependencies:

  1. second normal form.
  2. third normal form.
  3. fourth normal form.
  4. domain/key normal form.
  

Question 6 :
Relationships in a relational model between relations or tables are created by using:

  1. composite keys.
  2. determinants.
  3. candidate keys.
  4. foreign keys.
  

Question 7 :
Identify the use of HAVING clause.

  1. Acts like a WHERE clause but is used for groups rather than rows.
  2. Acts like a WHERE clause but is used for rows rather than columns.
  3. Acts like a WHERE clause but is used for columns rather than groups.
  4. Acts EXACTLY like a WHERE clause.
  

Question 8 :
___________is used to remove all rows from a table without logging the individual row deletions.

  1. DELETE
  2. REMOVE
  3. DROP
  4. TRUNCATE
  

Question 9 :
Identify the one which is not a valid binary operation in the relational algebra.

  1. Project
  2. Union
  3. Set Difference
  4. Cartesian Product
  

Question 10 :
Designer specified dependency rules in database design are known as _______

  1. Designer dependencies
  2. Database rules
  3. Functional dependencies
  4. Data Integrity
  

Question 11 :
The availability of same data at multiple places is known as

  1. Atomicity problem
  2. Data Inconsistency
  3. Data Isolation
  4. Data Redundancy
  

Question 12 :
Identify one of the following that cant be added in the CREATE TABLE command of SQL ?

  1. Names and data types of the table columns
  2. Primary keys and foreign keys of table
  3. default values for table columns
  4. Who is authorized to access the table
  

Question 13 :
The concept of Normalization IS NOT used for____________

  1. eliminating uncontrolled redundancy of data stored in the database.
  2. eliminating number of anomalies that could otherwise occur with inserts and deletes.
  3. ensuring that functional dependencies are enforced.
  4. reducing the number of joins required to satisfy a query.
  

Question 14 :
The DBMS is an interface between __________and _________components of a database system?

  1. Database application and the database
  2. Data and the database
  3. The user and the database application
  4. Database application and SQL
  

Question 15 :
Transaction processing is associated with everything given below except___________________

  1. Producing detail summary or exception report
  2. Recording a business activity
  3. Maintaining a data
  4. Conforming an action or triggering a response
  

Question 16 :
A _________ is a sequence of query and/or update statements.

  1. Commit
  2. Rollback
  3. Transaction
  4. Flashback
  

Question 17 :
Identify the column that cant be updated in the database.

  1. DATE type columns in the table
  2. Columns which allows NULL values in the table
  3. A primary key column which also serves as foreign key reference in another table
  4. TIME type column
  

Question 18 :
The command that is used to get back all the transactions back after rollback?

  1. Commit
  2. Rollback
  3. Flashback
  4. Redo
  

Question 19 :
_______________is the invalid data type in SQL.

  1. varchar
  2. numeric
  3. char
  4. Memo
  

Question 20 :
Consider money is transferred from (1)account-A to account-B and (2) account-B to account-A. Which of the following form a transaction?

  1. Only 1
  2. Only 2
  3. Both 1 and 2 individually
  4. Either 1 or 2
  

Question 21 :
________is used to show the number of instances of one entity can or must be associated with each instance of another.

  1. Cardinality constraint
  2. Entity instance
  3. Associative entity
  4. Multi-valued attribute
  

Question 22 :
Entity is nothing but a _________

  1. Object of relation
  2. Present working model
  3. Thing in real world
  4. Model of relation
  

Question 23 :
Select ID, p_name, allowance * 2.1 where project; The query given will not give an error. Which has to be replaced to produce the desired output?

  1. allowance*2.1
  2. ID
  3. Where
  4. Instructor
  

Question 24 :
Consider a relation R (A, B, C, D, E, F, G, H), where each attribute is atomic, and following functional dependencies exist. CH → G A → BC B → CFH E → A F → EG The relation R is __________ .

  1. in 1NF but not in 2NF
  2. in 2NF but not in 3NF
  3. in 3NF but not in BCNF
  4. in BCNF
  

Question 25 :
In an ER diagram, Instructor entity is the Parent entity and Employee entity is child entity. Then which of the following statement is correct?

  1. If Instructor is deleted, then Employee is also deleted
  2. If Employee is deleted, then instructor is also deleted
  3. Instructor can not be deleted
  4. Employee can not be deleted
  
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