Database

A database is a collection of persistent data.   This implies that the stored data can stand on its own and has some permanence. 

	Databases may include collections of information about people (names, addresses, etc.) or things (quantities, status, locations, etc.).
	The idea of permanence is that the data is maintained and even accumulated over a period of time.

Building Blocks of Databases

Building on the concept of the field, if we group a set of fields together, we have a record. 

A record is a grouping of facts that have some relationship.  For example: name, address, city, state, zip code, and phone number are examples of fields that describe characteristics of a person and make up a record. 

Therefore, a database is a collection of records that describe a group of things that share these characteristics.

Databases have three basic purposes:

1. To capture and manage potentially large sets of information.
2. To add, delete, and update the data in the database. 
3. To provide various ways to view the data in the database.

Databases can contain thousands and even millions of records.  They may be used to capture data on many transactions per second over hours, days, and even years.

A key feature of databases is that data can be appended to the database, removed as needed, and modified as desired.  Data is often fluid in the sense that it changes over time and many databases have powerful tools for maintaining the data.

Finally, what good is data if it cannot be retrieved and displayed?  Database software programs enable users to extract or query for one or more fields, single records, sets of records, and even summarize data for collections of records.  The result of a database query can be output to the screen, to a printer or exported to other applications.

From a business perspective, there are many ways to look at how databases are used:

	Inventory management: keeping track of goods, disposition, location, and transactions.
	Data warehousing: organizing and managing valuable corporate information.
	Sales: what was sold, who bought it, and for how much.
	Personnel management: who is doing what and when are they doing it.
	Time management: keeping track of the days, months, and years.

 Data Processing and Database Management Systems

A database management system (DBMS) is a software package that allows users to interact with data in a database.    The DBMS is responsible for defining the structure of databases  (i.e, file formatting), and how the data is accessed and processed.  Data processing is the actual effort of using a DBMS to accomplish work.

There are a number reasons for database processing including:

	Lowering costs – by centrally organizing information, it is now available to many users to make sound business decisions.
	Enables new ways to look at data – database processing allows you to access and retrieve data in ways that are useful to decision-making processes.
	Sharing of data- the most obvious benefit of allowing many to access data in central repository.
	Eliminating redundancy – a well-designed database can efficiently store information in a single place for maintenance and updating.
	Consistency – databases provide a centralized repository that is constant to the needs of the organization.
	Creating data integrity – centralized databases enable organizations to assure that data is reliable and accurate.
	Data Security – information is a valuable commodity to many organizations; databases enable you to know where it is at all times.
	Increase productivity – databases enable organizations to share information efficiently increasing performance and reducing costs.

 Database Applications and Systems

Database applications are software programs that support complex and potentially large sets of information.  A database system includes the software program and related elements such as the operating system and hardware.There are numerous database products that are available on the commercial market.  Some of these products include:

	Microsoft Access and FoxPro
	Oracle
	Sybase
	Microsoft SQL Server
	IBM DB2
	Informix
	Filemaker
	Gupta
	Xbase