A composite key is a primary key composed of multiple

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A composite key is a primary key composed of multiple columns used to identify a record uniquely In our database, we have two people with the same name Robert Phil, but they live in different places. Hence, we require both Full Name and Address to identify a record uniquely. That is a composite key.
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Second Normal Form (2NF) As per the Second Normal Form there must not be any partial dependency of any column on primary key. It means that for a table that has composite primary key, each column in the table that is not part of the primary key must depend upon the entire composite key for its existence. If any column depends only on one part of the composite key, then the table fails Second normal form . Rule 1- Be in 1NF Rule 2- Single Column Primary Key
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It is clear that we can't move forward to make our simple database in 2 nd Normalization form unless we partition the table above. We have divided our 1NF table into two tables viz. Table 1 and Table2. Table 1 contains member information. Table 2 contains information on movies rented. We have introduced a new column called Membership_id which is the primary key for table 1. Records can be uniquely identified in Table 1 using membership id NOTE: In Table 2, Membership_ID is the Foreign Key
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Foreign Key
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