Index on a table in the database is just like an index (or content page) in a book - a quick look at an index can tell you where the actual data is located. This saves time and cost of scanning the whole table, thus making the database faster.

It is a database, either a manual card index or an electronic computer system.

The word database is a noun that means a collection of data. Some words that are synonyms for database are directory, index, and table.

A database, as used by a computer, is a software programme that is used to store data (information).

A card index is also a database, written on pieces of card - so, technically, a card index is a physical thing (hardware?), possibly.

Table, index, trigger and column Table, index, trigger and column