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Primary key enforce entity integrity by uniquely identifying entity instances
Foreign key enforce referential integrity by completing an association between two entities
Candidate key is an attribute that can be uniquely used to identify a database record (Ex. Social security number in employee table)
Composite Key is combination of more than one attribute which uniquely identify a database record
Unique key is an attribute which can be used to identify a single record
Foreign key enforce referential integrity by completing an association between two entities
Candidate key is an attribute that can be uniquely used to identify a database record (Ex. Social security number in employee table)
Composite Key is combination of more than one attribute which uniquely identify a database record
Unique key is an attribute which can be used to identify a single record
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