Can you give examples of different transaction isolation levels?

Transaction isolation levels determine how and when the changes made by one transaction become visible to other transactions. The main isolation levels (according to the SQL standard) are:

• Read Uncommitted — the lowest level of isolation. A transaction can see uncommitted changes made by other transactions (dirty read).
• Read Committed — a transaction only sees committed changes. Dirty reads are prevented, but non-repeatable reads can occur.
• Repeatable Read — guarantees that if a row was read, a subsequent read will return the same data (prevents non-repeatable reads), but phantom reads can occur.
• Serializable — the strictest level, transactions are executed as if they were sequential, preventing phantom reads.

In Go, isolation levels are not set directly by the language, but when working with databases through drivers (e.g., database/sql), you can set the isolation level via SQL queries or transaction parameters.

Example of setting the isolation level in SQL:

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;