How does ORACLE retrieve information for the user?
The potential to answer an unlimited number of queries is basic to ORACLE, even queries which were not thought of when the database was created. Relational databases use each table within as a means of answering queries. Sometimes, the appropriate information to answer the query can be found in only one table. More often, ORACLE must go to two or more tables in order to retrieve the separate data elements which can answer the query — in other words, relational databases often “relate” the tables to one another to provide the answer to queries. The real power of a relational database lay in its ability to provide answers to almost every kind of query, even those not thought of when the database was originally designed or when the needs of users change over the course of time. ORACLE does this by using each table as the basic building block for larger, more complex tables. Complex tables are created whenever the user needs to answer specific queries which draw information from more than
