Isolation level for database transactions

The MySQL database provides us with four isolation levels:

①serializable (serialization): Can avoid dirty reading, non-repeatable reading, the occurrence of phantom reading.

②repeatable Read (Repeatable Read): Can avoid dirty read, non-repeatable read occurrence.

③read committed (Read Committed): Can avoid the occurrence of dirty reading.

④read UNCOMMITTED (READ UNCOMMITTED): lowest level, no case is guaranteed.

The top four isolation levels are the serializable level, the lowest is the read uncommitted level, and the higher the level, the lower the efficiency of execution. A level like serializable is a lock table (similar to a lock in Java Multi-threading) so that other threads can only wait outside the lock, so what isolation level to choose should be based on the actual situation. The default isolation level in the MySQL database is repeatable read (repeatable read).

In the MySQL database, the above four isolation levels are supported, the default is repeatable read (repeatable read), and in the Oracle database, only the serializable (serialization) level and Read Committed (Read Committed) levels are supported. The default is the Read committed level.

View the isolation level of the current transaction in the MySQL database:

Set the isolation level of the transaction in the MySQL database:

Or:

Isolation level for database transactions