Transaction Isolation

In database systems, isolation is a property that defines how/when the changes made by one operation become visible to other concurrent operations. Isolation is one of the ACID properties.

When Transaction Isolation is set to READ UNCOMMITTED, dirty reads are allowed--so one transaction can see uncommitted changes made by some other transaction.

For system where data integrity is very critical (for example banks and financial institutions) READ COMMITTED is used, to provide a higher level of data integrity.

Learn More:

• Transaction Isolation (tx_isolation):
  http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html#sysvar_tx_isolation