What is Entity relation?? How is works with Datawarehousing ETL modeling???

Showing Answers 1 - 5 of 5 Answers

Rangini vignesh

  • Aug 29th, 2006
 

Ans:Entity is nothing but an Object, it has characteristics.We call entity in terms of Logical view.The entity is called as a table in terms of Physical view.

The Entity relationship is nothing but maintaining a primary key,foreign key relation between the tables for keeping the data and satisfying the Normal form.

There are 4 types of Entity Relationships.

1.One-One,

2.One-Many,

3.Many-One,

4.Many-Many.

In the Datawarehouse modeling Entity Relationship is nothing but,a Relationship between dimension and facts tables(ie:Primary,foreign key relations between these tables).

The fact table getting data from dimensions tables because it containing primary keys of dimension tables as a foreign keys for getting summarized data for each record.

  Was this answer useful?  Yes

Entity is nothing but an object usually it is table containing the attributes(columns)ETL is a tool not a modeling .. it's useful for transfrering the data from the sources (hetogeniuos) to the target (warehouse) modeling is much useful for forming the fact's and dimension's which are used for decision making process using OLAP tools after forming the warehouse.

  Was this answer useful?  Yes

prav2000

  • Dec 21st, 2006
 

Majority of the times the DataWareHouse core tables are in a 3NF form and this is where your entity relationship comes into picture.

Further you can have fact and dimension tables which are populated using the core tables. The fact and dimension tables follow the star schema or snow flake schema.

  Was this answer useful?  Yes

Give your answer:

If you think the above answer is not correct, Please select a reason and add your answer below.

 

Related Answered Questions

 

Related Open Questions