SQL database-<...> transactions--Simple learning

Transaction

• First, what is a business
  Code control that ensures consistency of data, either committing commits or rolling back to the initial state of a transaction
• Second, the four characteristics of business: ACID
  A: atomicity-------transaction is not detachable, either executed or rolled back without intermediate state
  C: Consistency-------consistency before and after data
  I: Isolation-------transactions are not allowed to interfere in the course of execution
  D: Possession-------exist on the hard drive

Start transaction: BEGIN TRANSACTION or BEGIN TRAN or start transaction [transaction name]
Commit TRANSACTION: commit[Transaction name]
ROLLBACK TRANSACTION: Rollback

@ @error: Returns the error code of the previous SQL statement, no error returned 0

For example:
Method One: Use @ @ERROR and if to determine using transactions

Declare @t int        --record the accumulated error messageSet @t = 0begin Tran        --Start a transactionInsert  intoInfoValues('p003','吴倩','0','n004','1990-8-12')Set @t = @t +@ @ERROR    --Cumulative error messageInsert  intoInfoValues('p006','Zhang San','1','n004','1992-3-19')Set @t = @t +@ @ERROR    --Cumulative error messageInsert  intoInfoValues('p005','John Doe','0','n001','1991-12-24')Set @t = @t +@ @ERROR    --Cumulative error messageif @t<> 0        --Roll back if errors are found in the accumulationbegin    rollbackEndElse            --If no errors are found in the accumulation, submitbegin    CommitEnd

Law II: Use Try...catch .... To use transactions

-- Try...catch .... Statement begin  Try ... -- execute the statement here without error End Try begin catch ... -- If an error occurs, execute the statement here End Catch

begin TranbeginTryInsert  intoInfoValues('p007','Harry','0','n002','1991-4-1')    Insert  intoInfoValues('p009','Zhang Si','1','n004','1992-3-19')    Insert  intoInfoValues('p008','Li Nine','0','n001','1991-12-24')    CommitEndTrybeginCatchrollbackEndCatch

Other methods: You can nest transactions by using the IF statement

SQL database-<...> transactions--Simple learning