CPSC 322 Study Guide - Midterm Guide: Online Analytical Processing, Third Normal Form, Data Warehouse
Document Summary
Database: oltp: high volume of transactions (insert, update, Delete: detailed and current data, tables and joins are complex because they are normalized for rdbms (relational database management system) and this is done to reduce redundancy and to save space, entity-relational modelling techniques used for. Etl: infrastructure that facilitates the retrieval of data from operational databases into the data warehouses . Extracting: analytically useful data from operational data sources. Transforming: such data so that it conforms to the structure of the subject-oriented target data warehouse model while ensuring the quality of the transformed data. Important function of the transformation is data cleaning, may take 80% of the effort, and data warehouse is no longer normalized (ie. in 3nf form) instead it"s in star or snowflake schema, it is de-normalized. Loading: the transformed and quality assured data into the target data warehouse. This way, we can find the information for a single user very quickly.
