What Is Transaction Isolation Level?

Transactions are the heart of databases. They allow multiple users to access the same data while maintaining their integrity. If you've ever used a database before, you'll know there are different transaction isolation levels: read uncommitted, read committed, repeatable read, serializable, and the list goes on and on. Each class specifies how much data is visible to a statement in a transaction, specifically when the same data source is accessed by multiple transactions simultaneously. The transaction isolation level determines how many transactions can see the same data simultaneously. It's also known as "how much of the database is visible to each transaction."Isolation makes sure that each transaction is isolated from other concurrent transactions. It prevents unwanted side effects and non-reproducible results. There are three transaction isolation levels: Read uncommitted, Read Committed, and Repeatable read. Every query starts with a new view of the data in the read uncertain isolation level. In the read achieved isolation level, every question begins with a picture of the data as of the last commit. At the repeatable read isolation level, every query starts with a view of the data as of the previous commit and prevents non-repeatable reads of data. The importance of transaction isolation level lies in its ability to ensure accuracy. Accuracy is one of the ACID properties. An isolation level is a way to ensure that two transactions don't overlap and affect each other's data. Imagine you're trying to buy a coffee at Starbucks, but the person in front of you is trying to buy their entire day's coffee. If they pay for their order before you do, you might need more change! To prevent this from happening, the person working behind the counter will ask about your order and then ask the other customer theirs. It is similar to how isolation levels work in databases: they ensure that one transaction doesn't overlap with another transaction by giving each transaction its own space to operate without affecting anyone else's data.