what is read uncommitted isolation level
Read uncommitted is the weakest of the four transaction isolation levels defined in the SQL Standard (and of the six implemented in SQL Server).aving introduced read uncommitted isolation as the weakest of the available isolation levels, you should be expecting it to offer even lower isolation guarantees than locking read committed (the next highest isolation level).
Read Uncommitted. This is the lowest isolation level there is. Read uncommitted causes no shared locks to be requested which allows you to read data that is currently being modified in other transactions. It also allows other transactions to modify data that you are reading.his is the lowest isolation level there is. Read uncommitted causes no shared locks to be requested which allows you to read data that is currently being modified in other transactions. It also allows other transactions to modify data that you are reading.