Quadrant 2: Simple Data with Queries (Cont.)
| For security, a relational DBMS runs on a client-server architecture. Actual data files utilized in the database are specified as readable and writable only by the DBMS. |
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Two major applications for an SQL DBMS and 4GL client tools, for setting up forms for data entry and display, are
- Transaction processing: A transaction must be treated in a coherent and reliable way independent of other transactions.
- Data warehousing:
A data warehouse is a repository of integrated information from operational and legacy systems that provides the data for analytical processing and decision making. The warehouse design steps are
- Identify the data to be integrated.
- Construct an SQL schema for it.
- Buy a very large machine to hold the warehouse.
- Write a data pump to periodically copy data from each operational system into the warehouse.
- Run decision support queries against the data in the warehouse.
Data is typically stored in several distinct operational systems, and decision makers wish to access all of it to run decision support queries. For example, WalMart has a data warehouse with approximately two years of retail data. Retail warehouses examine customer buying pattern—what is selling and what is not. The results of such queries are used to rotate stock.
If you keep asking him about his ex-girlfriend, you‘.ll be on thin ice.