Copyright Intellipaat.com All rights reserved Part 2: Data Mart Informatica Introduction of Data mart and Informatica concepts What is Data Mart? Data Mart is a subset of Data warehouse that is designed for a particular line of
What is Data Mart? Data Mart is a subset of Data warehouse that is designed for a particular line of business, such as sales, marketing or finance.
In a independent data mart, data can derived from an enterprise-wide data warehouse.
In a independent data mart, data can be collected directly from sources.<br>
Ex: Name, Item, Date (these will use in Sales fact also in Purchase fact) Junk Dimension: A junk dimension is a collection of random transactional codes flags and/or text attributes that are unrelated to any particular dimension. The junk dimension is simply a structure that provides a convenient place to store the junk attributes.
Ex: Time and Date dimension (we can join both the dimensions in a single table, instead of providing 2 keys into the fact)<br>
Ex: Active, Auto generate no. Role-playing Dimension: Dimensions which are often used for multiple purposes within the same database are called role-playing dimensions.
Ex: A date dimension can be used for “date of sale", as well as "date of delivery", or "date of hire".<br>
Types of SCD
1. SCD Type 1 – Maintain the updated records (No history will maintain).
2. SCD Type 2 – Maintain the history of records.
3. SCD Type 3 – Maintain the history of records for the particular column. Rapidly Changing Dimension: Dimension which has attributes where values will be getting changed often.
Ex: Customer table has a field for rating attribute where the value changes very often.<br>
Ex: Passing null values into Id column to generate the fact values. Shrunken Dimension: A shrunken dimension is a subset of another dimension.
Ex: A source fact table may include a foreign key for Product, but the Target fact table may include a foreign key of Product Category, in this case we can create a small dimension for Product category as primary key.<br>
Ex: Percentages, ratios calculated. Factless fact: A fact table that contains no measures or facts
Ex: A fact table which has only product key and date key is a factless fact. There are no measures in this table. But still you can get the number products sold over a period of time.<br>
