what are the joins,primary key,foriegn key, candidate key,
super key and expain them?
Answer Posted / jebastin unnatha raja
Joins-> Joins allow You to view and retrive the data from multible related tables in a single result set.
Primary key-> A primary key is used to uniquely identify each row in a table.A primary key columns can not contain a nULL values.
foriegn key-> A foreign key is a field (or fields) that points to the primary key of another table. The purpose of the foreign key is to ensure referential integrity of the data
super Key-> A superkey is a combination of attributes that can be uniquely used to identify a database record. A table might have many superkeys.
Candidate key-> A candidate key is one that can identify each row of a table uniquely. Generally a candidate key becomes the primary key of the table.
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