13833523
Descripción
Test por Brandon Gagon, actualizado hace más de 1 año
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Creado por Brandon Gagon
hace casi 6 años
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Pregunta 1
Pregunta
The entity integrity rule requires that ____.
Respuesta
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all primary key entries are unique
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a part of the key may be null
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foreign key values do not reference primary key values
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duplicate object values are allowed
Pregunta 2
Pregunta
The referential integrity rule requires that ____.
Respuesta
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every null foreign key value must reference an existing primary key value
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an attribute have a corresponding value
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every non-null foreign key value reference an existing primary key value
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you delete a row in one table whose primary key does not have a matching foreign key value in another table
Pregunta 3
Pregunta
The ____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
Respuesta
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subtype discriminator
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inheritance
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specialization hierarchy
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entity supertype
Pregunta 4
Pregunta
Every subtype can have ____ supertype to which it is directly related.
Respuesta
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none
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only one
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one or many
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many
Pregunta 5
Pregunta
Every subtype can have ____ supertype to which it is directly related.
Respuesta
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none
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only one
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one or many
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many
Pregunta 6
Pregunta
A specialization hierarchy can have ____ levels of supertype/subtype relationships.
Respuesta
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none
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only one
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one or many
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many
Pregunta 7
Pregunta
The property of ____ enables an entity subtype to inherit the attributes and relationships of the supertype.
Respuesta
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subtype discriminator
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inheritance
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specialization hierarchy
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entity supertype
Pregunta 8
Pregunta
One important inheritance characteristic is that all entity subtypes inherit their ____ attribute from their supertype.
Respuesta
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primary key
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natural key
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foreign key
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surrogate key
Pregunta 9
Pregunta
What feature is a DDBMS disadvantage?
Respuesta
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Processor independence
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User-friendly interface
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Security
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Faster data access
Pregunta 10
Pregunta
What feature is a DDBMS advantage?
Respuesta
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Reduced operating cost
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Complexity of management and control
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Increased storage requirements
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Increased training cost
Pregunta 11
Pregunta
A database is composed of several parts known as database ____.
Respuesta
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sections
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fragments
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partitions
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parts
Pregunta 12
Pregunta
Under the ____ scenario, multiple processes run on different computers sharing a single data repository.
Respuesta
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Homogeneous
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a
Pregunta 13
Pregunta
The ____ scenario describes a fully distributed DBMS with support for multiple data processors and transaction processors at multiple sites.
Respuesta
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a
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b
Pregunta 14
Pregunta
____ distributed database systems integrate only one type of centralized DBMS over a network.
Respuesta
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Homogenous
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Heterogeneous
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Fully heterogeneous
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Fully homogeneous
Pregunta 15
Pregunta
____ transparency allows the integration of several different local DBMSs under a common, or global, schema.
Respuesta
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Transaction
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Performance
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Distribution
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Heterogeneity
Pregunta 16
Pregunta
The ____ contains the description of the entire database as seen by the database administrator.
Respuesta
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distributed global dictionary
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distributed data dictionary
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distributed global schema
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distributed data schema
Pregunta 17
Pregunta
____ fragmentation allows us to break a single object into two or more segments or fragments.
Respuesta
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Horizontal
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Vertical
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Data
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Mixed
Pregunta 18
Pregunta
With ____ data allocation, the database is divided into several disjointed parts and stored at several sites.
Respuesta
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centrialized
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decentralized
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partitioned
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replicated
Pregunta 19
Pregunta
The ____ rule requires that all copies of data fragments be identical.
Respuesta
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shared fragment
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mutual consistency
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horizontal fragmentation
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replication
Pregunta 20
Pregunta
Which of the following is a problem with a centralized database?
Respuesta
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high cost
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Good performance from remote locations
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Poor performance from the main location
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Lack of storage
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