The following the merge, when implemented, will produce the same duplicate data

Is under the concurrent and merge itself cannot ensure that data is not repeat?

Consult everybody a great god
Thank you

 
MERGE INTO A USING DUAL 
ON (id='XXX') 
WHEN NOT MATCHED THEN 
Insert (id) values (' XXX ') 

CodePudding user response:

The merge itself cannot ensure that data only, of course, the only is the only index or primary key or even applied to guarantee

CodePudding user response:

Uniqueness and merge data has nothing to do,

CodePudding user response:

Concurrent with this problem, if you want to avoid duplication, only with a unique constraint,