What is Normalization ?
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Answer Posted / shivag
The formal classifications describing the level of database
normalization in a data model are called Normal Forms (NF)
and the process of doing this is Normalization.
First normal form :
· A table is in first normal form when it contains no
repeating groups.
· The repeating column or fields in an un normalized table
are removed from the table and put in to tables of their
own.
· Such a table becomes dependent on the parent table from
which it is derived.
· The key to this table is called concatenated key, with the
key of the parent table forming a part it.
Second normal form:
· A table is in second normal form if all its non_key fields
fully dependent on the whole key.
· This means that each field in a table ,must depend on the
entire key.
· Those that do not depend upon the combination key, are
moved to another table on whose key they depend on.
· Structures which do not contain combination keys are
automatically in second normal form.
Third normal form:
· A table is said to be in third normal form , if all the
non key fields of the table are independent of all other non
key fields of the same table
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