[Solved] Which of the following is the correct way to start a transaction with REPEATABLE READ isolation level in PostgreSQL?BEGIN; -- your queries COMMIT; | PostgreSQL

PostgreSQL - Transactions and Concurrency

Which of the following is the correct way to start a transaction with REPEATABLE READ isolation level in PostgreSQL?

BEGIN;
-- your queries
COMMIT;

ASET TRANSACTION ISOLATION LEVEL REPEATABLE READ; BEGIN;

BBEGIN ISOLATION LEVEL REPEATABLE READ;

CBEGIN; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;

DBEGIN; SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL REPEATABLE READ;

Step-by-Step Solution

Solution:

Step 1: Recall correct syntax for setting isolation level
In PostgreSQL, you start the transaction with BEGIN, then set the isolation level for that transaction using SET TRANSACTION ISOLATION LEVEL.
Step 2: Match options to syntax
BEGIN; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; correctly shows BEGIN; then SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;. SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; BEGIN; sets isolation before BEGIN which is invalid. BEGIN ISOLATION LEVEL REPEATABLE READ; uses invalid syntax. BEGIN; SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL REPEATABLE READ; sets session level, not transaction level.
Final Answer:
BEGIN; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; -> Option C
Quick Check:
Set isolation after BEGIN = BEGIN; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; [OK]

Quick Trick: Set isolation level after BEGIN with SET TRANSACTION [OK]

Common Mistakes:

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Which of the following is the correct way to start a transaction with REPEATABLE READ isolation level in PostgreSQL?