Use plsql Developer to change the primary key

Using plsql Developer to change the primary key when you change the primary key through plsql Developer (plsql is a procedural language), if you only change the primary key, an error will be reported when you click Save, because you have not changed the primary key name. After you change the primary key name, when you insert it again, you will find that its primary key constraint is the same as before, because you have not deleted the index in plsql Developer, when creating a primary key, you will also create an index www.2cto.com to introduce an SQL statement to query duplicate data in the table. Select haoma from A group by haoma having count (*) & gt; 1