What is an “index”?
An “index” is another method used by ORACLE to facilitate information retrieval. An index is a pre-defined search path to data in the database. Indexes are files in the database which contain two items: the address of each record in the table and the matching key column (or field). Indexes can be either unique or non-unique, depending upon the nature of the information recorded on the database table. An example of an index created for the DOG table appears below: SQL> create index dogn on DOG(Breed_typ, Group_name) Searching for a record in an unindexed table is time-consuming for both the user and the database, as the search proceeds in a sequential order, moving through the table record by record to locate the appropriate records. Think of an index as the highway through which the data moves from its table location to the user. Another reason for indexes within a database is to maintain an optimum response time for all users. Response time is critical in ORACLE and indexing is necess
