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Q:

 Which of the following occurs when a transaction rereads data it has previously read and finds modification or deletions caused by a committed transaction?

A) Nonrepeatable read B) Phantom read
C) Dirty read D) Consistent read
 
Answer & Explanation Answer: A) Nonrepeatable read

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Q:

 A reason for using an SQL view to hide columns is:

A) to simplify a result only. B) to prevent the display of sensitive data only.
C) to accomplish both of the above. D) None of the above are reasons for using an SQL view.
 
Answer & Explanation Answer: C) to accomplish both of the above.

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Q:

 For what purposes are views used?

A) To hide rows only B) To hide columns only
C) To hide complicated SQL statements only D) All of the above are uses for SQL views.
 
Answer & Explanation Answer: D) All of the above are uses for SQL views.

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Q:

Which type of entity is related to two or more associated entities that each contain specialized attributes that apply to some but not all of the instances of the entity?

A) Supertype entity B) Subtype entity
C) Archetype entity D) Instance entity
 
Answer & Explanation Answer: A) Supertype entity

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Q:

Which of the following indicates the maximum number of entities that can be involved in a relationship?

A) Minimum cardinality B) Maximum cardinality
C) ERD D) Greater Entity Count (GEC)
 
Answer & Explanation Answer: B) Maximum cardinality

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Q:

 In the relational model, relationships between relations or tables are created by using:

A) composite keys. B) determinants.
C) candidate keys. D) foreign keys.
 
Answer & Explanation Answer: D) foreign keys.

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Q:

 The different classes of relations created by the technique for preventing modification anomalies are called:

A) normal forms. B) functional dependencies.
C) referential integrity constraints. D) None of the above is correct.
 
Answer & Explanation Answer: A) normal forms.

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Q:

Which of the following products implemented the CODASYL DBTG model?

A) IDMS B) DB2
C) dBase-II D) R:base
 
Answer & Explanation Answer: A) IDMS

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