What are the Most Common Types of Databases

There are many types of databases that vary by function and data model.

A database is an electronic file that stores information in a series of records. Records are often contained in one or more tables.

There are many types of databases that vary by function and data model.

On Browsing and Manipulating
One way to classify different types of databases is by their function:

• Look, but don't touch. Analytical databases, sometimes called On-line Analytical Processes (OLAP) are designed to assist in decision-making. Typically, an OLAP database contains statistical information that is read by users, but not modified.
• Change is good. Operational databases, also known as On-line Transaction Processing (OLTP) can be manipulated by users. Records can be added, deleted or modified by users with the proper level of access.

A Model Citizen
The second way to classify different types of databases is by their "data model." A data model describes the structure of data and how it is accessed. There are several common data models:

• Flat-file. Flat file databases most closely resemble paper files and file cabinets. Flat file databases, while simple to create and access, contain lots of redundant information. These redundancies slow down the search process, making the flat-file type of database inefficient.
• Hierarchical. Hierarchical databases relate tables in a parent/child format. Although this reduces redundancy and increases organization, it is still a limiting way to handle data. The fact that child tables at the same level don't have links to each other makes searching problematic.
• Relational. Relational databases link tables with common "key" fields allowing for sophisticated relationships between tables. Table links can be "indexed" or stored for future use, resulting in quicker searches in this type of database.
• Object-oriented. Object oriented databases are structurally similar to relational databases. While most other types of databases are designed to hold text and numbers, object-oriented databases are designed to store audio, video and other mixed media objects.