SQL Server Master----transactions from Getting Started

-------------Transaction----------------my understanding (when executing several statements, the other statements are not enough to be executed as long as one statement is unsuccessful)--transactions: The execution of multiple operations as a separate logical unit is a transactional--------Features: Multiple operations are successful only if they are successful, as long as there is an execution failure that should be the overall failure, success can be committed, failed can be rolled backGrammarbegin TransactionTr_insert--start Things (name pickbeginTryInsert  intoQ_user (Ulogname)Values('DSF') Insert  intoQ_user (Ulogname)Values('DSF')  --violates the UNIQUE KEY constraint "Uq__q_user__07e32c94386667d8". cannot be in the object "dbo." Insert duplicate key in Q_user. The repeating key value is (DSF). Will error --all successfully committed transactions Commit TranTr_insert--Here's the nameEndTrybeginCatch--Error getting exception ROLLBACK statement block rollback TranEndCatchSelect *  fromQ_userCreate procExectran@sql1  nvarchar( +),@sql2  nvarchar( +),@rtn nvarchar( +) Output asbegin TranTR_EXEC2beginTryexec @sql1    exec @sql2    Set @rtn='Success'    Commit TranExectranEndTrybeginCatchSet @rtn=@ @ERROR    rollback TranTR_EXEC2EndCatchGoDrop procExectranDeclare @rtn nvarchar( -)execExectran'INSERT into Q_user values (,,,,,,,,)','SQL2',@rtnOutputPrint @rtn

SQL Server Master----transactions from Getting Started