Logical Database Design(1st)

The entity integrity rule states that:

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no primary key may be equal to a value in a foreign key.
no primary key may be unique.
no primary key attribute may be null.
no primary key can be composite.

Normalization is a formal process for deciding which attributes should be grouped together in a relation.

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True
False

When mapping a regular entity into a relation which of the following is true?

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Two relations are created.
One relation is created.
Three relations are created.
Four relations are created.

When mapping a multivalued attribute into a relation which of the following is true?

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Four relations are created.
Three relations are created.
Two relations are created.
One relation is created.

If no multivalued attributes exist in a relation, then the relation is in what normal form?

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Third normal form
Second normal form
Fourth normal form
First normal form

Weak entities do not get mapped into a relation.

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True
False

A primary key is which of the following?

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An attribute that uniquely identifies each column
A derived attribute
Any attribute
An attribute that uniquely identifies each row

An enterprise key is a primary key whose value is unique for a given relation.

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False
True

A synonym is two or more attributes that have different names but the same meaning.

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False
True

A foreign key may be null and still adhere to the referential integrity constraint.

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False
True

A relation is a two-dimensional table.

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True
False

Relations are:

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two-dimensional tables.
four-dimensional tables.
five-dimensional tables.
three-dimensional tables.

A transitive dependency is which of the following?

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A relation that is in second normal form.
A functional dependency between two or more key attributes.
A functional dependency between two or more nonkey attributes.
A relation that is in first normal form.

A candidate key must uniquely identify each row.

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False
True

If a relation is in third normal form, it does not need to be in second normal form.

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True
False

The primary key in a relation does not need to be underlined.

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True
False

A null value is assigned when no other value applies.

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True
False

If no multivalued attributes exist and no partial dependencies exist in a relation, then the relation is in what normal form?

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First normal form
Fourth normal form
Second normal form
Third normal form

A relation has which of the following properties?

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The order of the columns is significant.
Each relation has a unique name.
Attributes can have the same name within a given table.
Each row is not unique.

The primary key of the new relation in a many-to-many relationship is a composite key comprised of the primary keys of each of the binary entities.

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False
True

A foreign key is which of the following?

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The same thing as a primary key
An attribute that serves as the primary key of another relation
Any attribute
An attribute that serves no purpose

The relational model consists of:

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operations using non-SQL languages.
unorganized data.
data redundancy.
data in the form of tables.

When mapping a binary many-to-many relationship into a relation which of the following is true?

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Four relations are created.
Three relations are created.
One relation is created.
Two relations are created.

When mapping a many-to-many unary relationship into a relation which of the following is true?

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One relation is created.
Three relations are created.
Two relations are created.
Four relations are created.

When mapping a ternary relationship with an associative entity into a relation which of the following is true?

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Two relations are created.
Four relations are created.
Three relations are created.
One relation is created.

A composite attribute does not get mapped into a relation.

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False
True

A primary key may be null.

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True
False

Well-structured relations encourage anomalies of data.

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False
True

When mapping a supertype/subtype relationship which of the following is true?

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There is no primary key/foreign key relationship between a supertype/subtype.
The supertype primary key is assigned to each subtype.
There is no link between the supertype/subtype entities.
The subtype primary key is assigned to each supertype.

In a 1:M relationship, the primary key on the one side migrates to the many side to become the foreign key on the many side.

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False
True

Logical Database Design(1st) : Question 1 of 30