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DBMS → Introduction to DBMS 33

Data redundancy refers to
Duplication of same data in multiple places
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Which level of abstraction describes HOW data is physically stored?
Physical level
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Which level of abstraction describes WHAT data is stored?
Logical level
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Which abstraction level provides customized views to end users?
View level
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The overall design of the database is called
Schema
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The collection of information stored at a particular moment is called
Instance
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Physical data independence means
Application programs do not depend on the physical schema
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A procedural DML requires the user to specify
What data is needed and HOW to get it
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A declarative DML requires the user to specify
Only what data is needed (not how)
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The DDL output is stored in
Data dictionary
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Which storage manager component fetches data from disk to memory?
Buffer manager
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Which type of user writes application programs?
Application programmers
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OLAP tools help which type of user?
Analysts/Sophisticated users
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In two-tier architecture, the application resides at
The client machine
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The DML compiler performs
Query optimization and generates evaluation plans
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Which is a disadvantage of DBMS?
Complexity and large memory usage
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An active data dictionary is updated
Automatically by DBMS with every database access
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A weak entity is one that
Depends on another entity and has no key attribute of its own
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A derived attribute is one that
Can be calculated from other attributes
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A multi-valued attribute can take
More than one value per entity instance
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The degree of a relationship is
Number of entity types involved
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In total participation every entity instance
Participates in the relationship
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A superkey is
A set of one or more attributes uniquely identifying a tuple
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A minimal superkey is called
Candidate key
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Referential integrity requires
Foreign key values to match existing primary key values in referenced relation
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NULL in a database represents
Unknown or non-existent value
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Which SQL language specifies the database schema?
DDL
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A schema diagram shows
Database schema with PK and FK dependencies
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Which storage manager component handles integrity constraints?
Authorization and integrity manager
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An attribute referencing PK of another relation is called
Foreign key
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Domain of an attribute is
Set of all possible valid values for that attribute
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Integrity constraints include
Domain, key, entity integrity, and referential integrity constraints
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Entity integrity constraint states
Primary key attributes must NOT be NULL
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DBMS → Relational Model 2

The relational model represents data using
Tables (Relations)
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A candidate key chosen as principal identifier is
Primary key
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DBMS → Data Models 1

Which data model uses entities and relationships?
Entity-Relationship Model
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DBMS → Transactions 2

A transaction is defined as
A collection of operations performing a single logical function
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The transaction manager ensures
Database remains in consistent state despite failures and manages concurrent transactions
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DBMS → ER Model 1

ER modeling is classified as which design approach?
Top-down approach
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DBMS → Database Security 1

Read authorization allows a user to
Only read data, not modify
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