You want to create a domain us_state_code that accepts only two uppercase letters representing US states. Which domain definition is correct?

hard📝 Application Q8 of 15

PostgreSQL - Advanced Features

You want to create a domain us_state_code that accepts only two uppercase letters representing US states. Which domain definition is correct?

ACREATE DOMAIN us_state_code AS char(2) CHECK (VALUE ~ '^[A-Z]{3}$');

BCREATE DOMAIN us_state_code AS varchar(2) CHECK (VALUE ~ '^[a-z]{2}$');

CCREATE DOMAIN us_state_code AS char(2) CHECK (VALUE ~ '^[A-Z]{2}$');

DCREATE DOMAIN us_state_code AS varchar(3) CHECK (VALUE ~ '^[A-Z]{2}$');

Step-by-Step Solution

Solution:

Step 1: Determine correct base type and length
US state codes are exactly two uppercase letters, so char(2) fits best.
Step 2: Verify regex pattern
The regex '^[A-Z]{2}$' matches exactly two uppercase letters, which is correct.
Final Answer:
CREATE DOMAIN us_state_code AS char(2) CHECK (VALUE ~ '^[A-Z]{2}$'); -> Option C
Quick Check:
Domain matches length and uppercase regex [OK]

Quick Trick: Match exact length and case in domain regex [OK]

Common Mistakes:

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