Database Design Oracle Section 4

A business rule such as "All accounts must be paid in full within 10 days of billing" is best enforced by: Creating a message to be printed on every bill that reminds the customer to pay within ten days. Making the relationship between CUSTOMER and PAYMENT fully mandatory and 1:1 on both sides. Creating additional programming code to identify and report accounts past due. Making the payment attribute mandatory.

Creating additional programming code to identify and report accounts past due.

A business rule such as "We only ship goods after customers have completely paid any outstanding balances on their account" is best enforced by: Creating additional programming code to verify no goods are shipped until the account has been settled in full. Making the payment attribute null. We need to trust our customers, and we know they will pay some day. Making the payment attribute optional.

Creating additional programming code to verify no goods are shipped until the account has been settled in full.

Why is it important to identify and document structural rules? Ensures we know what data to store and how that data works together. Ensures nothing. There are no benefits to be gained from documenting your Structural Business Rules. We need to concentrate on the Procedural Business Rules only. Ensures we know what processes are in place and how to program them. All of the Above.

Ensures we know what data to store and how that data works together.

A Supertype can have only one subtype. True or False?

False

A subtype is shown on an ERD as an entity with a one to many relationship to the supertype. True or False?

False

A supertype can only have two subtypes and no more. True or False?

False

You can only create relationships to a Supertype, not to a Subtype. True or False?

False

Why is it important to identify and document business rules? It allows you to create a complete data model and then check it for accuracy. It allows you to improve the client's business. It ensures that the data model will automate all manual processes. None of the above

It allows you to create a complete data model and then check it for accuracy.

How should you handle constraints that cannot be modeled on an ER diagram? Always let the network architect handle them Explain them to the users so they can enforce them All constraints must be modeled and shown on the ER diagram List them on a separate document to be handled programmatically

List them on a separate document to be handled programmatically

Can all constraints be modeled on an ER diagram? No, and those that cannot be modeled should be listed on a separate document to be handled programmatically No, in which case you should let the database administrator handle them Yes, all constraints must be modeled and shown on the ER diagram No, but you just explain them to the users so they can enforce them

No, and those that cannot be modeled should be listed on a separate document to be handled programmatically

All ER diagrams must have one of each of the following: (Choose two) At least one supertype and subtype One or more Entities Relationships between entities Arcs

One or more Entities Relationships between entities

Which of the following is true about subtypes? One instance of a supertype may belong to two subtypes. Subtypes should not be exhaustive. Subtypes must be mutually exclusive. Subtypes must not be mutually exclusive.

Subtypes must be mutually exclusive.

How would you model a business rule that states that girls and boys may not attend classes together? Supertype STUDENT has two subtypes BOY and GIRL which are related to GENDER, which is related to CLASS Use a supertype Make the attribute Gender optional Make the attribute Gender mandatory

Supertype STUDENT has two subtypes BOY and GIRL which are related to GENDER, which is related to CLASS

A new system would have a mixture of both Procedural and Structural Business Rules as part of the documentation of that new system. True or False?

True

A subtype can have a relationship not shared by the supertype. True or False?

True

A subtype is drawn on an ERD as an entity inside the "softbox" of the supertype. True or False?

True

All instances of a subtype must be an instance of the supertype. True or False?

True

How would you model a business rule that states that on a student's birthday, he does not have to attend his classes? Use a supertype Make the attribute Birthdate mandatory You cannot model this. You need to document it Use a subtype

You cannot model this. You need to document it

Which of the following is an example of a structural business rule? All employees must belong to at least one department. All products will have a selling price no less than 30 % greater than wholesale. All overdue payments will have an added 10 % late fee. Buildings to be purchased by the business must be current with earthquake building code.

All employees must belong to at least one department.