Databases and database management systems

A database is a collection of related data or facts arranged in a specific structure. A database management system (DBMS) is a program, or collection of programs, that allows multiple users to store, access, and process data or facts into useful information.
Three of the most important terms to know about databases are a table, a record, a field. Data is stored in tables. A table is divided into records (unnamed rows), and each record is divided into fields (named columns). The table consists of a set number of fields and an arbitrary number of records. For a record to exist, it must have data in at least one field.
To help you understand how a database stores data, think about a typical address book. Each piece of information in the address book is stored in its own location, called a field. For example, each entry has a field for First Name and another field for Last Name, as well as fields for Address, City, State, ZIP Code, and Phone Number. Each unique type of information

is stored in its own field. One full
Set of fields – that is, all the related information about one person or object – is called a record. Therefore, all the information for the first person is record 1, all the information for the second person is record 2, and so on.
A complete collection of records makes a table. Once you have a structure for storing data (whether it is a printed address book, phone book, or electronic table), you can enter and view data, create reports, and perform other tasks with the data.
For example, you may create a customer report that lists customers by ZIP Code.
A DBMS provides tools to perform data management functions: creating tables, sorting tables, entering and editing data, querying the database, viewing data, generating reports.
Many different DBMS programs are available. Enterprise-level products, such as Oracle, DB2, and Sybase, are designed to manage large special-purpose database systems. Programs such as Microsoft Access, Corel’s Paradox, and Lotus Approach are popular among individual and small-business database users.



Databases and database management systems