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DBMS → Introduction to DBMS 34

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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Concurrent access anomalies in file systems occur because
Multiple users update data simultaneously without coordination leading to inconsistency
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Security problem in file processing systems is that
Enforcing access constraints is difficult in ad hoc file-based systems
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A database-management system (DBMS) is
A collection of interrelated data AND set of programs to access those data
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Which symbol represents an entity in ER notation?
Rectangle
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Which symbol represents a relationship in ER notation?
Diamond
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A derived attribute is shown as
Dashed ellipse
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A multi-valued attribute is shown as
Double ellipse
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A weak entity is represented by
Double rectangle
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The identifying relationship of a weak entity uses
Double diamond
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Composite attribute in ER has
Ellipse with sub-component ellipses branching off
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A unary (recursive) relationship has degree
1
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A binary relationship has degree
2
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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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DBMS → Transactions 2

The transaction manager ensures
Database remains in consistent state despite failures and manages concurrent transactions
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Atomicity problems in file systems occur because
Operations like fund transfers may be partially completed during failures
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DBMS → Relational Model 1

A candidate key chosen as principal identifier is
Primary key
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DBMS → Views 1

The purpose of view level abstraction is to
Simplify user interaction by showing only relevant parts of database
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