How to guarantee uniqueness of a record using a complex key?












0















There is a simple table, with 3-rd foreign keys. How to make it impossible to re-record with the same values for these three keys? Create a complex key based on them?



And how to do it in the Workbench environment, just specify additionally each foreign key as a primary key?



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    0















    There is a simple table, with 3-rd foreign keys. How to make it impossible to re-record with the same values for these three keys? Create a complex key based on them?



    And how to do it in the Workbench environment, just specify additionally each foreign key as a primary key?



    enter image description here






    mysql sql







    share|improve this question

























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      0








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      1






      There is a simple table, with 3-rd foreign keys. How to make it impossible to re-record with the same values for these three keys? Create a complex key based on them?



      And how to do it in the Workbench environment, just specify additionally each foreign key as a primary key?



      enter image description here






      mysql sql







      share|improve this question














      There is a simple table, with 3-rd foreign keys. How to make it impossible to re-record with the same values for these three keys? Create a complex key based on them?



      And how to do it in the Workbench environment, just specify additionally each foreign key as a primary key?



      enter image description here






      mysql sql




      mysql sql






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 18 '18 at 1:38









      OPVOPV

      1,57721337




      1,57721337
























          1 Answer
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          If i get your question, you are looking to enforce uniqueness in the columns (user_id,position_id,organization_id).



          Assuming that at least one of the columns is (not null). If you were to create a unique index on the three columns it should work.



          CREATE UNIQUE INDEX index_name
          ON Employers(user_id,position_id,organization_id);






          share|improve this answer























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            1 Answer
            1






            active

            oldest

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            active

            oldest

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            active

            oldest

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            2














            If i get your question, you are looking to enforce uniqueness in the columns (user_id,position_id,organization_id).



            Assuming that at least one of the columns is (not null). If you were to create a unique index on the three columns it should work.



            CREATE UNIQUE INDEX index_name
            ON Employers(user_id,position_id,organization_id);






            share|improve this answer




























              2














              If i get your question, you are looking to enforce uniqueness in the columns (user_id,position_id,organization_id).



              Assuming that at least one of the columns is (not null). If you were to create a unique index on the three columns it should work.



              CREATE UNIQUE INDEX index_name
              ON Employers(user_id,position_id,organization_id);






              share|improve this answer


























                2












                2








                2







                If i get your question, you are looking to enforce uniqueness in the columns (user_id,position_id,organization_id).



                Assuming that at least one of the columns is (not null). If you were to create a unique index on the three columns it should work.



                CREATE UNIQUE INDEX index_name
                ON Employers(user_id,position_id,organization_id);






                share|improve this answer













                If i get your question, you are looking to enforce uniqueness in the columns (user_id,position_id,organization_id).



                Assuming that at least one of the columns is (not null). If you were to create a unique index on the three columns it should work.



                CREATE UNIQUE INDEX index_name
                ON Employers(user_id,position_id,organization_id);







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 18 '18 at 2:31









                George JosephGeorge Joseph

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