: is a single characteristic or attribute of a person, place, object, event, or idea. E.g.
customer ID, first name, last name, company name, address, phone number, contract type,
contract signing date, and contract amount.
: is a collection of fields that describe a person, place, object, event, or idea. E.g.
Customer ID, first name, last name, phone
: the specific value, or content, of a field.
: this set of field value. E.g. the data for each customer is stored as a separate record.
Database: or relational database
; a collection of related table. You connect the records in the
separate tables through a COMMON FIELD that appears in both tables.
A primary key
is a field, or a collection of fields, whose values uniquely identify each record in
. The customer ID field is referred to as the primary key of the customer table. No two
records can contain the same value for the primary key field.
A foreign key
: the primary key from one table as a field in a second table to form a relationship
between the two tables.
Relational database management systems
A database management system (DBMS) is a software program that lets you create databases
and then manipulate data in them.
A relational database management system
It allows you to create database structures containing fields, tables, and table
It lets you easily add new records, change field values in existing records, and
It contains a built-in query language, which lets you obtain immediate answers to
the questions you ask about your data.