The first step in transforming an extended E-R model into a relational database design is to ________.
answer
create a table for each entity
question
Each attribute of an entity becomes a(n) ________ of a table.
answer
column
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The identifier of the entity becomes the ________ of the corresponding table.
answer
primary key
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The ideal primary key is ________.
answer
short, numeric, and fixed
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A surrogate key should be considered when ________.
answer
the key contains a lengthy text field
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Which of the following is not true about surrogate keys?
answer
They are nonunique within a table.
question
One of the important properties of a column is whether or not it is ________.
answer
required
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In a relational database design, all relationships are expressed by ________.
answer
creating a foreign key
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Which of the following would be a reason to denormalize a relation?
answer
Improve performance
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Which of the following is true about representing a weak entity with the relational model?
answer
If the weak entity is ID-dependent, the key of the parent entity must be part of the key of the weak entity.
question
Which of the following is true when representing a 1:1 binary relationship using the relational model?
answer
The key of either entity is placed in the other as a foreign key.
question
Which of the following is the correct technique for representing a 1:N relationship in the relational model?
answer
The key of the entity on the one side is placed into the relation for the entity on the many side.
question
Given the tables
TABLE_A (Attribute1, Attribute2, Attribute3)
TABLE_B (Attribute4, Attribute5, Attribute6)
as shown in the figure below, which of the following would display the correct placement of foreign keys in the relational model?
Given the tables
PRODUCT (ProductID, Description, Cost)
SUPPLIER (SupplierID, ContactName, PhoneNumber)
as shown in the figure below, which of the following would represent the correct placement of foreign keys?
Which of the following is the correct technique for representing a M:N relationship using the relational model?
answer
An intersection relation is created, and the keys of both parent entities are placed as a composite key in the intersection relation.
question
Given the tables
PRODUCT (ProductID, Description, Cost)
SUPPLIER (SupplierID, ContactName, PhoneNumber)
as shown in the figure below, which of the following would represent the correct placement of foreign keys?
answer
PRODUCT (ProductID, Description, Cost)
SUPPLIER (SupplierID, ContactName, PhoneNumber)
PRODUCT_SUPPLIER (ProductID, SupplierID)
*ProductID in PRODUCT
SupplierID in SUPPLIER
Both in PRODUCT_SUPPLIER
question
In many-to-many relationships in a relational database design, ________.
answer
a.) the key of the child is placed as a foreign key into the parent
b.) the key of the parent is placed as a foreign key into the child
c.) the keys of both tables are placed in a third table
d.) the keys of both tables are joined into a composite key
*e.) C and D
question
In many-to-many relationships in a relational database design, ________.
answer
a.) the intersection table is ID-dependent on one of the parents
b.) the intersection table is ID-dependent on both of the parents
c.) the minimum cardinality from the intersection table to the parents is always M
d.) A and B
*e.) B and C
question
In relational database design, ID-dependent entities are used to ________.
answer
represent N:M relationships
question
When transforming an E-R data model into a relational database design, the key of the parent entity should be placed as part of the primary key into the child entity ________.
answer
when the child entity is ID-dependent
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When transforming an ID-dependent E-R data model relationship into a relational database design and the child entity is designed to use a surrogate key, then ________.
answer
the relationship changes to a non-ID-dependent relationship
question
What relationship pattern is illustrated in the following schema?
PRODUCT (ProductID, Description)
SUPPLIER (SupplierID, ContactName, PhoneNumber)
PRODUCT_SUPPLIER (ProductID, SupplierID, Cost)
ProductID in PRODUCT_SUPPLIER must exist in ProductID in PRODUCT
SupplierID in PRODUCT_SUPPLIER must exist in SupplierID in PRODUCT
answer
Association relationship
question
What relationship pattern is illustrated in the following schema?
VEHICLE (VehicleID, Cost)
CAR (VehicleID, NumberOfSeats)
TRUCK (VehicleID, CargoCapacity)
VehicleID in CAR must exist in VehicleID in VEHICLE
VehicleID in TRUCK must exist in VehicleID in VEHICLE
answer
Supertype/subtype relationship
question
Which of the following is not true about representing subtypes in a relational database design?
answer
All of the attributes of the supertype are added to the subtype relations.
question
What relationship pattern is illustrated in the following schema?
EMPLOYEE (EmployeeID, OfficePhone, Manager)
Manager in EMPLOYEE must exist in EmployeeID in EMPLOYEE
answer
Recursive relationship
question
Which of the following is NOT true of recursive relationships?
answer
Even when the relationship is 1:N, a new table must be defined to represent the relationship.
question
Microsoft Access does not create N:M relationships because:
answer
Microsoft Access creates databases based on database designs instead of data models.
question
As far as Microsoft Access is concerned, there are no:
answer
N:M relationships.
question
By default, when Microsoft Access creates a relationship between two tables, it creates a(n):
answer
1:N relationship.
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To create a 1:1 relationship between two tables in Microsoft Access:
answer
the Indexed property of the foreign key column must be set to Yes (No Duplicates).
question
After a 1:1 relationship has been created between two tables in Microsoft Access, the Relationship Type of One-To-One appears:
answer
in the Edit Relationships dialog box.
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