In the broadest sense, a database is anything that stores data. A
phone book, for instance, could be considered a database as it
stores related pieces of information such as name and phone
number. However, in the world of computers, a database usually refers to
a collection of related pieces of information stored
electronically. Aside from the ability to store data, a database
also provides a way for other computer programs to quickly retrieve and
update desired pieces of data.
The central concept of a database is that of a collection of
records, or pieces of knowledge. Typically, for a given database,
there is a structural description of the type of facts held in
that database: this description is known as a schema. The schema
describes the objects that are represented in the database, and
the relationships among them. There are a number of different ways
of organizing a schema, that is, of modelling the database structure:
these are known as database models (or data models).
The most common model for a database is a relational model. These
databases are organized by fields, records, and tables. A field is
a single piece of information; a record is one complete set of
fields; and a table is a collection of records. With this simple model,
just about any relationship between any collection of data can be
represented.
No comments:
Post a Comment