Tata Consultancy Services
Parte da empresa Tata Group
Empresa engajada
Pergunta de entrevista da empresa Tata Consultancy Services
Difference between unique key and primary key?
Resposta da entrevista
Sigiloso
15 de mar. de 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.