What give you more flexibility and control when changing data, and they ensure data consistency in the event of user process failure or system failure.
Answers
Explanation:
1.Reverse Engineering is the process of creating a conceptual or logical model by extracting the information from an existing data source.
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True (*)
False
Correct
2.A column or set of columns that uniquely identifies each row in a table.
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Foreign Key
Database Key
Primary Key (*)
Correct
3.A Supertype can have only one subtype. True or False?
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True
False (*)
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4.A relationship that participates in an entity’s unique identifier is called a Hierarchical Relationship.
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True
False (*)
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Section 5
(Answer all questions in this section)
5.A column or combination of columns in one table that refers to a primary key in the same or another table.
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Candidate Key
Primary Key
Foreign Key (*)
Super Key
Correct
6.An Entity Relationship model does not highlight the physical and database constraints. It is essential to transform the ER model into a relational model which can serve as the basis for defining the physical implementation of the database.
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True (*)
False
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7.When an exclusive relationship is engineered to a Relational model, a foreign key column is created for each relationship included in the arc.
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True (*)
False
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8.When two attributes in the same entity relate to the same unique identifier attribute then you can fold the keys into one column in the Relational model during engineering.
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True (*)
False
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9.A primary unique identifier in an entity is transformed to a Unique Key in a table.
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True
False (*)
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10.For a mandatory 1:1 relationship, the foreign key will be placed on the mandatory side of the table and will use the NOT NULL constraint to enforce the mandatory condition.
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True (*)
False
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11.You can specify multiple columns after the DISTINCT qualifier.
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True (*)
False
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12.To eliminate duplicate rows in the result, include the DISTINCT keyword in the SELECT clause.
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True (*)
False
Correct