Database datasets have common characteristics; these characteristics can identify information needed. A RDBMS takes these characteristics and matches the data to other data found in the data set. This gives information that users can understand and identify. What good is data if the user that needs it cannot understand the information given? It turns into a spread sheet stored on a hard drive and never used. Relational databases allow a user to bring things together to compare. A database manager can take four or five databases and pull certain information out and into one database. This groups the information together depending on the user's desire. This is accomplished by relational database management system or RDBMS.
RDBMS is the preferred way to keep data such as medical information, military information, financial logs, personal records, and manufacturing data. The relations in each database are added to tables. The tables are named or structured to explain the type of data the table holds. Depending on what is needed depends on what is actually in the database. For example if a database holds all women in United States Army and the user requests every woman in the United States Army under 35. The database administrator would run the script to pull out every woman under the age of 35 by the date of birth and branch of service. Databases allow a person to take out a collection of information based on values, combinations and constraints of what is needed. The information can be pulled out of one set of databases and put into another database based on the relation of the information. Rational databases are convenient to pull only the information that is needed for the purpose. This takes out all information that is irrelevant so the information is specific to what is wanted from it.
Rational databases are the easy and convenient way to manipulate information. In most situations the RDBMS will work fine and is probably used the most. Software like Oracle and MySQL are excellent applications that have been used for years for rational databases. Sometimes there are times that a more robust database is needed to provide a better resolution.
ODBMS or object oriented databases in the form of objects which are harder to use so relational databases are used more wildly. ODBMS are used for specialized departments or areas. The objects are set up by the database developer so the developer can make one object persistent or a bunch of objects connected to a single cell or object. Object oriented databases are used for a more complex situation. Some data is buried deep and is not organized at all for this situation. Some data is in graphs or in a tree structure. This data is referenced to other data so the link could be very thin but the link is still there but is not in a column or row.
Common Types of Databases: