What is second normal form in DBMS?

Answer 1

Second normal form is valid in a table which have composite primary key which is made with the combination of two columns.So if we have A,B,C,D,E attributes in our table and C,D are fully functional dependent on A,B.But E is partially functional dependent on A,B,Mean if we use Only B to define E coloumn then that will be suffecent.so then we use 2nd normal form & we create two tables with coloumns attributes A,B,C,D and the other table with coloumns attribute B,E.That will be called second normal form.

Answer 2

A relation is in 2NF if it contains no repeating groups, and no partial key functional dependencies. Rule is that a relation in 1 NF with a single key field must be in 2NF. 1 relation for the attributes that are fully dependent upon the key.

Answer 3

Second normal form (2NF) in DBMS states that a table is in 2NF if it is in 1NF and all attributes that are not part of the primary key are fully functionally dependent on the whole primary key. This means that each non-key attribute is fully dependent on the primary key, and not on a subset of the key.