How/what Is Denormalisation Or Denormalization

Sep 1, 2006

Hi

I came accross recently the term denormalisation basically the article that i read in a magazine said after normalising a database you should follow "by tactical denormalisation to improve database performance."

My questions are:

- What is denormali(z/s)ation? (my understanding is after you normalise you go back in reverse using some sort of technique?)?

- Does it increase performance?

- can any one give example of how it can be used... where the performance is greater than the normalised way?

thanks

View 6 Replies

Table Denormalization

Nov 20, 2007

I have a table that looks like this:

acct payment product product description
1 10.00 1 book
1 20.00 2 lamp
2 10.00 1 book
2 300.00 3 blackberry
2 60.00 4 drawer

how would i denormalize this table in t-sql so that it would look like this:

acct payment1 product1 product1 descr payment2 product2 product2 descr payment3 product3 product3 descr
1 10.00 1 book 20.00 2 lamp
2 10.00 1 book 300.00 3 blackberry 60.00 4 drawer

Thanks in advance.

View 6 Replies

May 22, 2007

Hi All,

Bit of a funny one. I have two tables, lets call them PetOwner and Pets

PetOwner

OwnerID OwnerName
1 Tim
2 Paul
3 Andy

Pets
OwnerID PetName
1 Tricia
1 Louise
2 Bill
2 Ben
2 David
2 Topsy
3 Flopsy
3 Mopsy

And I need to write a query that returns a resultset like this

OwnerID OwnerName PetName1 PetName2 PetName3 PetName4 PetName5
1 Tim Tricia Louise NULL NULL NULL
2 Paul Bill Ben David Topsy Flopsy
3 Andy Flopsy Mopsy NULL NULL NULL

Can anyone help?

N.B. A pet owner can only have a maximum of 5 pets, but even if no-one in the database has 5 pets, the PetName5 column must still appear (but have a value of NULL).

View 13 Replies

May 28, 2008

Hi,
I was reading that many of these high traffic websites actually have 2 databases, 1 database is used ONLY for reads, while the other is for writes.

How does one go about creating such a setup? How does the database where writes are allowed replicated the data to the read only database server?

View 1 Replies

View Related

How/what Is Denormalisation Or Denormalization

Denormalisation

Table Denormalization

Query To Represent Denormalization Of Data

Denormalization, 2 Databases , 1 Read 1 Write Db