| noramlization [message #163840] |
Mon, 20 March 2006 05:38  |
eswaries
Messages: 41
Registered: January 2006
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Member |
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Can any one explain noramlisation with oracle? don't say refer websites.if please tell the website address.i want noramlisation with oracle.
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| Re: noramlization [message #172293 is a reply to message #163840] |
Mon, 15 May 2006 20:28  |
harman_deep
Messages: 8
Registered: August 2005
Location: Amritsar
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Junior Member |
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Well Normalization is an Independent concept ..not related to any database.
1st normal form --atomic state of individula cells that is one element contains one thing only..practically speaking
2nd normal form---- 1st NF + all the non key attributes must depend uponi key attribute transitively and irrtransiteviely ....means there must be Primary key and other columns which are not part of PK must depend upon PK either straight way or by other meanns
(a,b)(PK)--->c
c---->d
===> (a,b)-->d
here both c and d repends upon PK
Also other thing non-key elements must not depend on part of PK
ie
c-->d is there then it is NOT IN 2nd Normal form
such things to be removed by making a seprate table for them
3rd Normal ----2nd Normal Form + Non key attributes should be directly dependent and not through other elemnts..
As shown above
c---->d
===> (a,b)-->d
This is NOT ALLOWED in 3rd NF ...New table must be created to remove this
so in new table
1 table
(a,b)-->c
1 table
c-->d
So 2 tables are formed..
I hope the above examples will help
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