Why to create Datamart
- To partition data in order to impose access control strategies.
- To speed up the queries by reducing the volume of data to be scanned.
- To segment data into different hardware platforms.
- To structure data in a form suitable for a user access tool.
- Identify the Functional Splits
- Identify User Access Tool Requirements
- Identify Access Control Issues
Steps to determine that data mart appears to fit the bill
Identify the Functional Splits
In this step we determine that whether the natural functional split is there in the organization. We look for departmental splits, and we determine whether the way in which department use information tends to be in isolation from the rest of the organization. Let’s have an example…
Suppose in a retail organization where the each merchant is accountable for maximizing the sales of a group of products. For this the information that is valuable is:
- sales transaction on daily basis
- sales forecast on weekly basis
- stock position on daily basis
- stock movements on daily basis
As the merchant is not interested in the products they are not dealing with, so the data marting is subset of the data dealing which the product group of interest. Following diagram shows data marting for different users.
Issues in determining the functional split:
- The structure of the department may change.
- The products might switch from one department to other.
- The merchant could query the sales trend of other products to analyze what is happening to the sales.
These are issues that need to be taken into account while determining the functional split.
Identify User Access Tool Requirements
For the user access tools that require the internal data structures we need data mart to support such tools. The data in such structures are outside the control of data warehouse but need to be populated and updated on regular basis.
There are some tools that populated directly from the source system but some cannot. Therefore additional requirements outside the scope of the tool are needed to be identified for future.
Populated from the data warehouse rather each tool must have its own data mart.
Identify Access Control Issues
There need to be privacy rules to ensure the data is accessed by the authorized users only. For example in data warehouse for retail banking institution ensure that all the accounts belong to the same legal entity. Privacy laws can force you to totally prevent access to information that is not owned by the specific bank.
Data mart allows us to build complete wall by physically separating data segments within the data warehouse. To avoid possible privacy problems the detailed data can be removed from the data warehouse. We can create data mart for each legal entity and load it via data warehouse, with detailed account data.
Posted by Vissicomp Technology Pvt Ltd