Tata Consultancy Services
Fait partie de Tata Group
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Question d’entretien chez Tata Consultancy Services
Difference between unique key and primary key?
Réponse à la question d'entretien
Utilisateur anonyme
15 mars 2018
Unique key means for every tuple we have a unique value for unique key.There can be one or more or none unique keys in any table. Primary key is ' unique' and 'not null' key which is used to differentiate the tuples. There can be only one primary key.