Database Management System DBMS
A database management system dbms is a collection of programs that are used to create and maintain a database. DBMS is a general-purpose software system that provides the facility to define structure of database, to insert, delete, update and retrieve specific data to generate reports.
Relational Database Model
Relational database model invented by Dr. R. F. Codd to solve the data integrity and data redundancy problems by using mathematics rules. In a relational database model, data is stored in relations. Relation is another term used for table. A table in a database has a unique name that identifies its contents. Every table have a column that uniquely identifies each row in the table.
The following DBMS MCQs set contains the mcqs of entity relationship models, extended entity relationship model, relationship attributes in entity relationship model, entity relationship modeling and normalization, data integrity, types of database constraints, components of entity relationship model, types of entities, types of attributes, relational database model, relational database management system, relational keys and types of relations.
This DBMS MCQs series may help you to prepare NTS educators, PPSC lecturer computer science, Database administrator, database manager, database developer and other computer related jobs test.
Database Management System MCQs With Answers Set 6
1. An identifier of an entity instance?A). Must be unique
B). May be unique
C). May consists of more than one attribute
D). a and b
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2. Which type of identifier is used to identify a set of instances of a given entity?
A). Unique
B). Non-unique
C). Instance
D). None of above
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3. Depending on the system being modeled, a relationship can have entities?
A). 1
B).2
C). 3
D). All
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4. The degree of a relationship refers to the:
A). Number of entities
B). Maximum cardinality
C). Minimum cardinality
D). Number of attributes in the identifiers
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5. A weak entity is one which _____?
A). Does not have a unique identifier
B). Is not in a relationship with any other entities
C). Cannot exist in the database by itself
D). Is a subtype
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6. A subtype entity_____?
A). Contains optional attributes not contained in super type
B). Inherits attributes of its supertype
C). Is always mutually exclusive
D). a and b
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7. Cardinality expresses number of entity occurrences associated with one occurrence of the related entity
A). The specific
B). Undetermined
C). Predetermined
D). Programmed
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A).Minimum
B). Maximum
C). Exact
D). Maximum and minimum
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9. A _____ attribute need not be physically stored within the database
A).Single valued
B). Derived
C). Multi valued
D). Composite
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10. A _____ relationship exists when 3 entities are associated.
A). Unary
B). Binary
C). Ternary
D). Weak
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11. Attributes may share a_____?A). Domain
B). Name
C). Location
D). Table
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12. Which of the following might be represented with a single valued attribute
A).Person's phone number
B). Car's color
C). Employees educational background
D). Computer processor speed
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13. If an entity can exist apart from one or more related entities it is said to be _____ independent.
A). Existence
B). Relationship
C). Business
D). Weak
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14. A Relationship is an association between_____?
A). Fields
B). Objects
C). Entities
D). Databases
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A). Ensured that duplicate records are not entered into the table
B). Control who is allowed access to the data
C). Prevent users from changing the values stored in the table
D). Improve the quality of data entered for a specific property
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16. Which of the following can be addressed by enforcing a referential integrity constraint?
A). Information on the customer must be known before anything can be sold to dad customer
B). All phone numbers must include the area code
C). Certain fields are required such as the email address or phone number before the record is accepted
D). None of these
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17. _____ is a special type of integrity constraint that relates two relations and maintains consistency across the relations.
A). Domain constraints
B). Referential integrity constraints
C). Entity integrity constraints
D). Domain integrity constraints
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18. Drop table cannot be used to drop a table referenced by a _____ constraint.
A). Primary key
B). Local key
C). Composite key
D). Foreign key
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19. _____ is preferred method for enforcing Data integrity.A). Constraint
B). Triggers
C). Stored procedure
D). Cursors
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20. _____ express the number of entities to which another entity can be associated via a relationship set.
A). Relational cardinality
B). Mapping cardinality
C). Participation constraints
D). None of the above
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