![]() We identify the real world objects (Entities) involved in the given problem domain, their properties (Attributes), their relationships (One-to-One, One-to-Many, etc) with other objects and so on. Given a problem statement to design a DB, what do we do? How do we start designing? We apply the concepts of ER model. To understand the Dimensional Modelling, let us first review database design using ER modelling in brief. So, how do we design a DW? The answer is using the Dimensional Modelling. Now, knowing that a DW is not be designed for the transaction processing or the data manipulation, but for analysis, the use of ER modelling and Normalization for DW design is completely ruled out. And this makes database systems most suitable for the transaction processing also termed as On-Line Transaction Processing (OLTP). These two processes, ER modelling and Normalization, eliminate the redundancy of data which is main culprit for various anomalies that would have arisen otherwise. ![]() A database is designed using ER modelling which is followed by the process of Normalization once the ER diagram is mapped to the relational schema. The efficacy of database systems in storing, retrieving and managing data lies in the design of the database that it is storing. Unlike, a database system whose main purpose is to store and retrieve data efficiently, the goal of a Data Warehouse (DW) system is to perform analysis of data efficiently. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |