Rolling back with a savepoint

Building upon the last exercise, it turns out that banks with more than $6 million in MMDAs are twice as likely to sustain during a downturn than those with between $5 and 6 million in that same asset class. Here I've made a mistake in the sample code, and we need to rollback to the save point to maintain data integrity.

Este exercício faz parte do curso

Transactions and Error Handling in PostgreSQL

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Instruções do exercício

Inside a transaction set FIELD48 to 'MMDA+' where RCON6810 (MMDA amount) is greater than $6 million.
Set mmdaplus_flag_set as a savepoint.
Set FIELD48 to 'MMDA+' where RCON6810 (MMDA amount) is greater than $5 million (this is a mistake).
Undo back to mmdaplus_flag_set, end the transaction, and count the 'MMDA+' records.

Exercício interativo prático

Experimente este exercício completando este código de exemplo.

BEGIN;

-- Set the flag to MMDA+ where the value is greater than $6 million
UPDATE ffiec_reci set FIELD48 = 'MMDA+' where RCON6810 > 6000000;

-- Set a Savepoint
___ mmdaplus_flag_set;

-- Mistakenly set the flag to MMDA+ where the value is greater than $5 million
UPDATE ffiec_reci set FIELD48 = 'MMDA+' where ___ > 5000000;

-- Rollback to savepoint
___ TO ___;

COMMIT;

-- Select count of records where the flag is MMDA+
SELECT count(FIELD48) from ffiec_reci where FIELD48 = 'MMDA+';

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