pts Question 21 Given the ERD below which of the following relational designs is
ID: 3810884 • Letter: P
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pts Question 21 Given the ERD below which of the following relational designs is appropriate? (The primary key is underlined and the foreign key is in italics in the answers.) The ERD models the following: A customer may have many meter readings but he/she may be a new customer have no meter readings. A meter reading is for one and only one customer. NOTE: A meter reading occurs when a utility worker comes to your facility/house and examines a water meter or an electric meter. These meters have numbers on them that indicate how much water or electricity you have used since the last reading. CUSTOMER METER READING Belongs To MeterID CustomerID First Name Date Reading Has Last Name O CUSTOMER (CustomerD, First Name, Last Name) METER READING (MeterlDu Date, Reading) O CUSTOMER (CustomerD, First Name, Last Name) METER READING (MeterlDr Date, Reading, CustomerfD) O CUSTOMER (CustomerD, FirstName, Last Name, MeterD METER READING (MeterlD, Date, Reading) O CUSTOMER (CustomerlD, First Name, Last Name) METER READING MeterlD, Date, Reading) O CUSTOMER (CustomerD, First Name, Last Name, MeterD METER READING MeterDi Dater Reading, CustomerExplanation / Answer
Question 21:
b option is correct, Because customer id is as foereign jey in the Meter table. which will satisfy all the given constraints in the figure.
Question 22:
d option is corroect, Since mateID is foruegn key in the species table it will fulfill the given requirement.
Question23:
b option is correct, because Actor_Studio is defining the relationship given between actor and Studio which is many to many with the help of foreign key.
Question 24:
Option c is correct, Because multiple meter readings are allowed and with the help of foreign key constraint the condition will be satisfied.
Question 25:
c option is correct here.
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