An important part of ACID: Data isolation
Data isolatingCreating Fully-isolated Transactions in a Multithreaded Environment Is A Non-Trivial Exercise. There Are Three Ways Isology Can Be Violated:
Lost Update: One Thread Reads The Record, And THREAD UPDATES The Record, And The First Thread Overwrites The Second Thread's Update. Thread 1 Read a record, thread 2 updated a record, then thread 1 overwrinktate the update of thread 2 . Dirty Read: Thread One Writes Data; Thread Two Reads What Thread One Wrote. Thread One Then Overwrites The Data, Thus Leaving Thread Two with Old Data. Thread 1 Write data, thread 2 reads the data written by thread 1 . Thread 1 changed the data, and finally the thread 2 is not updated old data. UnrepeATable read: Thread One Reads Data; The data is the daread one Tries to re-read the data but it it has change. Thread 1 reads the data; however, this data is then modified by thread 2. Thread 1 attempts to read data from new, but data has been modified.
Solution for MultiUser Updates:
To Prevent this Kind of Problem, You May Use any of the folload starting:
