Consider Figure 8.20.

a. Write a domain integrity rule for Balance.

b. Write a triggering operation for the Balance attribute for the event of inserting a new ACCOUNT.

Figure 8.20

Transcribed Image Text:

ACCOUNT Account Number Balance WITHDRAWAL Is for Date Time Amount Name: Account_Number Meaning: Customer account number in bank Meaning: Dollar amount of transaction Data type: Character Name: Amount Data type: Numeric Format: 2 decimal places Range: 0-10,000 Uniqueness: Nonunique Null support: Non-null Format: nnn-nnnn Uniqueness: Must be unique Null support: Non-null User rule: WITHDRAWAL Amount may not exceed ACCOUNT Balance Event: Insert Entity Name: WITHDRAWAL Condition: WITHDRAWAL Amount > ACCOUNT Balance Action: Reject the insert transaction