Beginning Database Design- P11:This book focuses on the relational database model from a beginning perspective. The title is, therefore, Beginning Database Design. A database is a repository for data. In other words, you can store lots of information in a database. A relational database is a special type of database using structures called tables. Tables are linked together using what are called relationships. You can build tables with relationships between those tables, not only to organize your data, but also to allow later retrieval of information from the database | Understanding Data Warehouse Database Modeling The demands of the modern global economy and the Internet dictate that end user operational applications are required to be active 24 7 365 days a year. There is no window for any type of batch activity because when people are asleep in Europe others are awake down under in Australia. The global economy requires instant and acceptable servicing of the needs of a global user population. In reality the most significant difference between OLTP databases and data warehouses extends all the way down to the hardware layer. OLTP databases need highly efficient sharing of critical resources such as onboard memory RAM and have very small I O requirements. Data warehouses are completely opposite. Data warehouses can consume large portions of RAM by transferring between disk and memory in detriment to an OLTP database running on the same machine. Where OLTP databases need resource sharing data warehouses need to hog those resources for extended periods of time. So a data warehouse hogs machine resources. An OLTP database attempts to share those same resources. It is likely to have unacceptable response times because of a lack of basic I O resources for both database types. The result therefore is a requirement for a complete separation between operational OLTP and decision-support data warehouse activity. This is why data warehouses exist The Relational Database Model and Data Warehouses The traditional OLTP transactional type of relational database model does not cater for data warehouse requirements. The relational database model is too granular. Granular implies too many little pieces. Processing through all those little-bitty pieces is too time consuming for large transactions joining all those pieces together. Similar to the object database model the relational database model removes duplication and creates granularity. This type of database model is efficient for front-end application performance involving small amounts of
