Data is the second level of knowledge

FILE BASED SYSTEM is One way to keep information on a computer is to store it in permanent files.

foreign key can have null values

..... is simply a collection of records, which contains logically related data

......... contains a logically connected set of one or more fields

File represents some characteristic of the real-world object that is being modelled

FILE-BASED SYSTEMS DISADVANTAGES:

Database is an organized shared collection of related data used to support the activities of a particular organization.

Traditional database applications

Multimedia databases

Data warehouses systems:

........ is data about data

In Data Base information stored in the catalog is called Meta-Data,

NOSQL systems require meta-data.

In DB insulation between the programs and data is also called program-data independence.

DB multiple views of the data

........... s the intermediate layer between the database and the programs that access the data.

........... is collection of programs that enables users to create and maintain a database and control access to them.

the primary key cannot have a NULL value, so the candidate key with a NULL value can be the primary key