Transaction isolation levels

Transaction isolation levels determine how and when the changes made by one transaction become visible to others. The main isolation levels are:

1. Read Uncommitted — a transaction can see changes made by other transactions even if they are not yet committed. Dirty reads are possible.
2. Read Committed — a transaction only sees committed changes. It prevents dirty reads but allows non-repeatable reads.
3. Repeatable Read — guarantees that data read by 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 anomalies.

In Go, when working with databases via database/sql, you can set the isolation level through the driver or SQL queries, for example:

trx, err := db.BeginTx(ctx, &sql.TxOptions{
    Isolation: sql.LevelSerializable,
})