KEYS IN RDBMS (PRIMARY KEY, SUPER KEY, CANDIDATE KEY)
KEYS IN RDBMS (Data Constraints) Many keys are available in the RDBMS, They allow finding the relation between columns and table that help identify a tuple (row) in a table. They help find a unique record from the table or database. Keys are seven types in RDBMS Primary key Super key Alternate key Foreign key Candidate key Unique key Composite key Fig 1.2 KEYS 1. PRIMARY KEY A primary key is an attribute (columns) of a table or group of columns that uniquely identify each record in a table. This contains a unique value that’s no repetition for any row. It cannot be a null value. A table contains only one primary key. Example:- Roll_no Name class ...
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