Solved

data warehouse - star schema

Posted on 2011-02-21
2
1,277 Views
Last Modified: 2012-05-11
Hello

I'm just reading/learning about the data warehouse star schema. Lets take what seems to be the canonical example of a star schema, where you have a sales fact table and product/store/customer etc dimension tables. Here is an example from oracle

http://download.oracle.com/docs/cd/B10501_01/server.920/a96520/schemas.htm#12896

 The sales table would have fields such as quantity_sold and cost and then keys for each dimension

I'm getting a bit confused with the traditional 3NF form of this model where you would have a 1:N relationship between customers and orders and a M:M relationship between orders and products. Here is a picture of what i mean

http://download.oracle.com/docs/cd/B10501_01/server.920/a96520/schemas.htm#14651

Using the star schema, what would happen for a sale that had multiple products? Would there be one row per product sold in the central fact table and this row would 'duplicate' the key information  (i.e. each product in the same sale would have the same key for each dimension such as customer/store/date etc)

thanks
0
Comment
Question by:andieje
2 Comments
 
LVL 10

Accepted Solution

by:
APNFSSC earned 500 total points
ID: 34947458
Using the star schema, what would happen for a sale that had multiple products? Would there be one row per product sold in the central fact table and this row would 'duplicate' the key information  (i.e. each product in the same sale would have the same key for each dimension such as customer/store/date etc)

Yes that is correct.

I tend to use a combination of 3NF and Snowflake... I just find that is most flexible.
0
 

Author Closing Comment

by:andieje
ID: 34947566
thanks
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Determine next b-weekly date 12 89
syadmin MSSQL 2 66
Question about Relationship and Userform in Access Database 17 54
Exchange 2007 standard - defrag (eseutul /d) 10 42
This article describes some very basic things about SQL Server filegroups.
SQL Command Tool comes with APEX under SQL Workshop. It helps us to make changes on the database directly using a graphical user interface. This helps us writing any SQL/ PLSQL queries and execute it on the database and we can create any database ob…
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

773 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question