DBMS 20 Important MCQ For Competitive Exams
1. The output of the Data Definition Language is stored in the
A) view table
B) schema
C) metadata
D) all of the above.
Ans: (C)
2. The overall design of a database is called
A) Subschema of the database
B) Schema of the database
C) Structure of the database
D) View of the database
Ans: (B)
3. Object based data models are used in describing the abstraction of the following levels?
A) Conceptual and view
B) Only physical
C) Physical and conceptual
D) Only conceptual
Ans: (A)
4. An association of several structure of a data base can be expressed graphically by?
A) Tuple
B) Record
C) Relationship
D) Field
Ans: (C)
5. Triggers can be used for replicating databases.
A) True
B) False
Ans: (D)
6. In an object oriented model, one object can access data of another object by passing?
A) Instance variable
B) Variable
C) Message
D) Function
Ans: (C)
7. The collection of information stored in a database at a particular moment is?
A) View
B) Instance
C) Scheme
D) None of these
Ans: (B)
8. In two- phase locking protocol the two phases are
A) growing phase and shrinking phase
B) execution phase and blocking phase.
C) running phase and sleeping phase.
D) none of the above
Ans: (A)
9. The ________ states that a foreign key must either match a primary key value in another relation or it must be null.
A) entity integrity rule
B) referential integrity constraint
C) composite attribute
D) action assertion
Ans: (A)
10. Three SQL, DDL, CREATE commands are
A) Schema, Base and Table
B) Schema, Table and View
C) Base, Table and Schema
D) Key, Base and Table
Ans: (B)
11. In the architecture of a database system external level is the
A) physical level.
B) logical level.
C) conceptual level
D) view level.
Ans: (D)
12. An entity set that does not have sufficient attributes to form a primary key is a
A) strong entity set.
B) weak entity set.
C) simple entity set.
D) primary entity set.
Ans: (B)
13. In a Hierarchical model records are organized as
A) Graph.
B) List.
C) Links.
D) Tree.
Ans: (D)
14. In an E- R diagram attributes are represented by
A) rectangle.
B) square.
C) ellipse.
D) triangle.
Ans: (C)
15. In case of entity integrity, the primary key may be
A) not Null
B) Null
C) both Null & not Null.
D) any value.
Ans: (A)
16. Volatile storage
A) loses its contents when power is switched off.
B) doesn’t loses its contents when power is switched off.
C) creates backup when power is switched off.
D) none
Ans: (A)
17. The language used in application programs to request data from the DBMS is referred to as the
A) DML
B) DDL
C) VDL
D) SDL
Ans: (A)
18. A logical schema
A) is the entire database.
B) is a standard way of organizing information into accessible parts.
C) describes how data is actually stored on disk.
D) both A) and C)
Ans: (A)
19. Related fields in a database are grouped to form a
A) data file.
B) data record.
C) menu.
D) bank.
Ans: (B)
20.The database environment has all of the following components except:
A) users.
B) separate files.
C) database.
D) database administrator.
Ans: (A)
