Prevent dirty reads
You have to analyze how many accounts have more than $50,000.
As the number of accounts is an important result, you don't want to read data modified by other transactions that haven't committed or rolled back yet. In doing this, you prevent dirty reads. However, you don't need to consider having non-repeatable or phantom reads.
Prepare the script.
Den här övningen är en del av kursen
Transactions and Error Handling in SQL Server
Övningsinstruktioner
- Set the appropriate isolation level to prevent dirty reads.
- Select the count of accounts that match the criteria.
Interaktiv övning med praktiskt arbete
Testa den här övningen genom att slutföra den här exempelkoden.
-- Set the appropriate isolation level
SET TRANSACTION ___ ___ ___ ___
-- Count the accounts
SELECT ___(*) AS number_of_accounts
FROM accounts
WHERE current_balance >= 50000;