Types+Of+Databases

**media type="custom" key="4399675"Databases Classified by Data Model** A **data model** defines the struture of information to be contained in a database, how the database will use the information, and how the different items in the database relate to each other. The goal of a database model is to identify and organize the database contents in a logical way.


 * [|Flat File Databases]**
 * database contains only one table or file //(lacks the ability to interrelate data in an organizational structure)//
 * simple and easy to use
 * slower to respond because records must be searched sequentially
 * generally consume more disk space
 * [|Relational Databases]**
 * //Fields// can be shared among all files in the database, making it possible to connect them
 * A file is called a //table// (consists of rows and columns)
 * A record is called a //tuple//
 * A field is called an //attribute//


 * [[image:j0254446.gif align="left"]] [|Object-Oriented Databases] **
 *  stores data in the form of objects //(units of object-oriented programming logic)//
 * object contains data related to the object and the actions to be performed on the object
 * <span style="color: #0000ff; font-family: 'Comic Sans MS',cursive;">faster development and access times; speeds up database functions and makes database development easier
 * [|Multimedia Databases] -** allows storage of pictures, movies, sounds, and hyperlinked fields


 * [|Hybrid Databases] -** A database is not limited to employing a single data model. Several different models may be used to allow more effective data handling. A combination of relatonal and object-oriented database models is a popular form of hybrid database. Combining data models allows for more sophisticated analysis within the framework of the relational database.

A **Data Warehouse** is used to store data gathered from one or more databases. Unlike operational databases, data warehouses do not change, delete, or manipulate the information they store. Law informent records are one example of a data warehouse, with vast collections of photgraphs and arrest records on file for reference or for statistical use.
 * Databases Classified by Function** - The two major functional classifications for databases are //operational databases// and //data warehouses.//
 * [|Operational databases]** are working systems that are continually being updated. They are ususally used to track an operation or situation, such as the inventory of a store. E-commerce Web sites are bases on operational databases. These sites allow users to place items in a virtual shopping cart and enter credit card and shipping information without ever talking to a person. A distributed database is spread across mulitple networked computers, with each computer storing a portion of the total amount of data. Distributed databases offer advantages in cost, expandability, and storage capability, however; they do operate as quickly as mainframe or supercomputer databases, where all information is contained on one computer.