Database management systems allow users to store bits of information, organize and retrieve part or all of the information as needed. Each of the major types of database management systems requires a software program that creates records to organize the data and creates reports from that data. Database software programs create one of four common types: hierarchical databases, network databases, relational databases, or object-oriented databases.
A database management system makes it possible to manage all the databases on a hard drive using a single computer program.
The hierarchical database is one of the oldest types of database management systems. It is most commonly used on mainframe computers. The database creator pre-defines the relationships between each record and its data. The framework requires a root, or parent, record from which the database designer creates a parent-child relationship for each bit of data that goes into the database.
A network database organizes data using defined parent-child relationships.
A network database also organizes data using defined parent-child relationships. Like a real family, the network’s database structure allows data classified as a child to have more than one parent. This is an improvement over hierarchical types of database management systems. It allows users to connect information in one database to another dataset through parent record and child record.
The relational database management system has increased in popularity due to its flexibility and ease of use. It allows the database designer to use individual information to create relationships between separate databases without the restriction of parent or owner relationships. Information in one database that links it to data in a different database is a unique identifier, such as an employee identification number.
Relational database management systems allow database designers to create a database to store employee payroll and salary information. The designer creates a separate database for personal information such as home addresses and phone numbers. Different users can insert and update records in each database. Reports extract data from records in any database where the corresponding employee ID number is found.
Object-oriented types of database management systems provide a way to organize data other than numbers and text. Designers use them to accommodate multimedia items such as photos, music, and videos. This database management system uses two identifiers for each item. The first is a descriptive object name, and the second is a miniature program with instructions or methods that the computer executes during storage and retrieval. The two parts become an object that database users can organize as they do with text or numbers.