What is normalization and what are the different forms of
normalizations?
Answer Posted / swapna
Normalization is the process of efficiently organizing data
in a database. There are two goals of the normalization
process: eliminate redundant data (for example, storing the
same data in more than one table) and ensure data
dependencies make sense (only storing related data in a
table). Both of these are worthy goals as they reduce the
amount of space a database consumes and ensure that data is
logically stored.
First normal form (1NF) sets the very basic rules for an
organized database:
? Eliminate duplicative columns from the same table.
? Create separate tables for each group of related data and
identify each row with a unique column or set of columns
(the primary key).
Second normal form (2NF) further addresses the concept of
removing duplicative data:
? Meet all the requirements of the first normal form.
? Remove subsets of data that apply to multiple rows of a
table and place them in separate tables.
? Create relationships between these new tables and their
predecessors through the use of foreign keys.
Third normal form (3NF) goes one large step further:
? Meet all the requirements of the second normal form.
? Remove columns that are not dependent upon the primary
key.
Finally, fourth normal form (4NF) has one additional
requirement:
? Meet all the requirements of the third normal form.
? A relation is in 4NF if it has no multi-valued
dependencies
Is This Answer Correct ? | 28 Yes | 3 No |
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