Cierto o Falso Capítulo 4

1. 1Whether a developer uses an E-R model or a semantic object model, the eventual database design that is created should be exactly the same.

   1. ATrue
   2. BFalse
2. 2The semantic object model is different from object-oriented database processing.

   1. ATrue
   2. BFalse
3. 3Semantic objects represent the users’ perceptions more closely than the E-R model.

   1. ATrue
   2. BFalse
4. 4Unlike entities, semantic objects are not grouped into classes.

   1. ATrue
   2. BFalse
5. 5An “identifier” is a named collection of attributes that sufficiently describes a distinct identity.

   1. ATrue
   2. BFalse
6. 6Semantic objects represent distinct identities.

   1. ATrue
   2. BFalse
7. 7A semantic object must represent something with a physical existence.

   1. ATrue
   2. BFalse
8. 8Attributes of a semantic object that contain only a single element are called link attributes.

   1. ATrue
   2. BFalse
9. 99. A simple attribute has only one element.

   1. ATrue
   2. BFalse
10. 10An attribute that contains a group of other attributes is called a composite attribute.

    1. ATrue
    2. BFalse

11. 11Semantic object attributes are used to establish a relationship between one semantic object and another.

    1. ATrue
    2. BFalse
12. 12All attributes of a semantic object are collectively referred to as “semantic object attributes”.

    1. ATrue
    2. BFalse
13. 13For simple attributes in a semantic object model, only the maximum cardinality needs to be indicated.

    1. ATrue
    2. BFalse
14. 14The cardinality of a group attribute is inherited by all the attributes in that group.

    1. ATrue
    2. BFalse
15. 15The cardinalities of an attribute operate only between the attribute and the container of the attribute.

    1. ATrue
    2. BFalse
16. 16Object attributes are always paired attributes.

    1. ATrue
    2. BFalse
17. 17An object identifier is an attribute or group of attributes that always uniquely identifies object instances.

    1. ATrue
    2. BFalse
18. 18Object identifiers may or may not be unique.

    1. ATrue
    2. BFalse
19. 19The cardinality of an object identifier is almost always 1.1.

    1. ATrue
    2. BFalse
20. 20The domain of simple and group attributes include both a physical description and a semantic description.

    1. ATrue
    2. BFalse
21. 2121. The domain of an object attribute is a dynamically enumerated list containing all object instances of a particular type.

    1. ATrue
    2. BFalse
22. 22The portion of a semantic object that is visible to a particular application is called the “application object”.

    1. ATrue
    2. BFalse
23. 23An attribute that is computed from other values has a “formula domain”.

    1. ATrue
    2. BFalse
24. 24A “simple object” is a semantic object that contains only single-value object attributes.

    1. ATrue
    2. BFalse
25. 25A “simple object” can contain only simple attributes.

    1. ATrue
    2. BFalse
26. 26A “composite object” is exactly like a “simple object” except that it contains at least one attribute with a maximum cardinality greater than 1.

    1. ATrue
    2. BFalse
27. 27A “composite object” can not contain more than one multi-valued attribute.

    1. ATrue
    2. BFalse
28. 28It is possible to include a multi-valued simple attribute within a multi-valued group attribute.

    1. ATrue
    2. BFalse
29. 29A “compound object” contains at least one multi-value, simple or group attribute but no object attributes.

    1. ATrue
    2. BFalse
30. 30A “compound object” can contain no multi-value attributes.

    1. ATrue
    2. BFalse
31. 31A semantic object that has a multi-value group attribute containing an object attribute is called a “hybrid object”.

    1. ATrue
    2. BFalse
32. 32A “hybrid object” is a semantic object that relates two or more objects and stores data that are peculiar to that relationship.

    1. ATrue
    2. BFalse
33. 33Parent attributes appear as the first attribute of a subtype object and are always required.

    1. ATrue
    2. BFalse
34. 34Subtype attributes in the parent object always have a minimum cardinality of 1.

    1. ATrue
    2. BFalse
35. 35The parent object inherits all of the attributes of the subtype object.

    1. ATrue
    2. BFalse
36. 36A semantic object can not have more than one subtype attribute.

    1. ATrue
    2. BFalse
37. 37From a semantic object perspective, an entity in an E-R model represents only a portion of the data in the users’ model of that entity in their environment.

    1. ATrue
    2. BFalse

Description

#serenaparaalola

Author

Angel Perez

Language

Español

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5

History

Created on 17 Sep 2016 · updated on 27 Sep 2016

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