Can you list the transaction isolation levels you know?

Main transaction isolation levels commonly used in databases:

• Read Uncommitted — a transaction can see changes made by other transactions before they are committed, which can lead to "dirty" reads.
• Read Committed — a transaction only sees data that has been committed, preventing dirty reads.
• Repeatable Read — guarantees that data read in a transaction will not change until the transaction completes, preventing non-repeatable reads.
• Serializable — the strictest level, providing full transaction isolation as if transactions were executed sequentially.

Each level balances between performance and degree of isolation; the choice depends on application requirements.