Mainly achieved by way of view: a database which will create a view, when access to the logical view prevail.
Read uncommitted: Direct returns the latest value on the record, there is no view of the concept of
reading Submitted: in each beginning execution of SQL statements to create a view, so SQL query before execution if the data changes, you can also read.
repeatable read: view created in the transaction starts, all with the view during the existence of the entire transaction, so read data does not change.
serialization: is directly locked manner to avoid concurrent access.
