Read Mode and isolation levels
The Read Mode field controls the isolation level for transactions when loading a collection, permitting or preventing dirty reads.
The setting UNCOMMITTED implements dirty reads, in which no shared locks are issued and no exclusive locks are honored. It is possible to read uncommitted data; values can be changed and rows can appear or disappear in the collection before the end of the transaction. The setting corresponds to the Transact-SQL statement SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED.
The setting COMMITTED specifies that shared locks are held while data is being read to avoid dirty reads, but the data can be changed before the end of the transaction. The setting corresponds to the Transact-SQL statement SET TRANSACTION ISOLATION LEVEL READ COMMITTED.
The Read Mode field overrides the default value for Collection Read Mode set in the core form Process Defaults.