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.

Deze oefening maakt deel uit van de cursus

Transactions and Error Handling in PostgreSQL

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Oefeninstructies

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.

Praktische interactieve oefening

Probeer deze oefening eens door deze voorbeeldcode in te vullen.

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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