Add primary key to existing table

Question

I have an existing table called Persion. In this table I have 5 columns:

• persionId
• Pname
• PMid
• Pdescription
• Pa

Answer 1

If you add primary key constraint

ALTER TABLE  ADD CONSTRAINT  PRIMARY KEY   


for example:

ALTER TABLE DEPT ADD CONSTRAINT PK_DEPT PRIMARY KEY (DEPTNO)

    

             

                                                        
            
            

              
                
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