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Explain how normal forms can be transformed from lower to higher(DBMS)
In the database management system there are several rules to manage the tables and do the changes like insertion, deletion, updatation and there are different stages at which the tables are organized and these stages are known as normal forms.
It is a standard structure of relational databases in which a relation may be inserted in another relation.
Five normal forms
There are five normal forms which are explained below −
First normal form
The first normal form defines the definition of the table. The rules of the first normal form are as follows −
- Each column must have a single value.
- Each column has a unique name.
- Value must have the same type of data.
- All the records are different.
Second Normal Form
The second normal form must satisfy the condition of first normal form and no partial dependency on any of the column. Partial dependency means {A,B} → {C} but also {A} → {C} then {C} is partially functionally dependent on {A,B}.
Third Normal form
The third normal form satisfy the condition of the second normal form and every non key attribute is non-transitively dependent on the primary key. Transitively dependent means by the roll number of the student we can obtain all the details like name address phone number so it is not done in third normal form.
Fourth Normal form
The fourth normal form must follow the criteria of third normal form and the key attribute must depend on key column and attribute of row in a table are not come more than one in a table means if there are two teachers of one subject so you can study by only one teacher not by both.
Fifth Normal form
The fifth normal form must satisfy the condition of the fourth normal form and break down the table to eliminate the redundancy and anomaly and re-join the table by the candidate key. We don't lose any original data and no new table will arise.
These are the five normal forms to manage the database.
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