What levels of transaction isolation do you know?

Transaction isolation levels determine how concurrent transactions interact with data and what anomalies are possible. The main isolation levels, standardized by SQL, are as follows:

1. Read Uncommitted — a transaction can see changes made by other transactions before they are committed. Dirty reads are possible.
2. Read Committed — a transaction only sees data that has been committed by other transactions. It prevents dirty reads but allows non-repeatable reads.
3. Repeatable Read — guarantees that data read in a transaction will not change until the transaction completes. It prevents non-repeatable reads but allows phantom reads.
4. Serializable — the strictest level, transactions are executed as if they were sequential, preventing all types of anomalies.

In Go, when working with databases through packages like database/sql, the isolation level can be set via driver parameters or SQL queries (e.g., SET TRANSACTION ISOLATION LEVEL ...). The specific support depends on the database management system used.