You want to ensure that a birthdate column in a persons table only accepts dates in the past. Which constraint would best enforce this rule?

hard📝 Application Q15 of 15

SQL - Table Constraints

You want to ensure that a birthdate column in a persons table only accepts dates in the past. Which constraint would best enforce this rule?

AUNIQUE (birthdate)

BNOT NULL

CCHECK (birthdate < CURRENT_DATE)

DPRIMARY KEY (birthdate)

Step-by-Step Solution

Solution:

Step 1: Identify constraint to limit date values
To restrict birthdate to past dates, a CHECK constraint comparing birthdate to CURRENT_DATE is needed.
Step 2: Evaluate options
CHECK (birthdate < CURRENT_DATE) uses CHECK (birthdate < CURRENT_DATE), which enforces the rule. NOT NULL only requires a value, UNIQUE and PRIMARY KEY do not limit date range.
Final Answer:
CHECK (birthdate < CURRENT_DATE) -> Option C
Quick Check:
CHECK constraints enforce value rules [OK]

Quick Trick: Use CHECK with date comparison for valid date ranges [OK]

Common Mistakes:

MISTAKES

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