Types of Databases

Data is any piece of information, whereas database is defined as an integrated collection of logically related data, which is stored in electronic files (records) for easy access. The storage of data in a database allows the user to access the information for various purposes.

Databases are electronic filing systems that store data in the form of fields, records, etc. Some databases may provide access rights which allow the user to perform various operations such as edit, update, delete, etc., on data items.

Firstly, we have classified databases depending on their storage purpose and capabilities.

Analytical databases are read-only type of databases. These can be mostly seen online, on the web; wherein you can see a collection of items present, but you cannot modify them. You can consider this to be like inventory catalogs. The best instance would be any online shopping site that jots down the available products and data about them.

The information stored in analytical databases is mostly extracted from operation databases or external databases. This is mostly screened and edited data which is often used by the management of the organization. It is expressed as a summary of the organization's or employee's performance or sales, marketing records, etc. 

The main purpose of an analytical database is to allow the user to analyze the data, depending on which a management policy can be formulated.

It is a digital database that stores data into tables in the form of rows and columns. Each row has a unique key (its identity, mostly primary key). This helps linking one table to another (which is referred as foreign key).

In general, each entity has a table―the row being its instance, and the columns are the values attributed to the instances. In this type of database, all the data is stored and retrieved with the help of 'relations', which are nothing but collection of tables; hence the name 'relational database'.

Operational databases store information needed for the operations of an organization. This is mostly a detailed information about a particular person or an employee, department, or subject. Therefore, they are also called Subject Area Databases (SADB). Thus, these databases are based on functional lines of an organization.

These databases store the entire information in a single location―the centralized computing facility. Users at various locations can access this data through a computer network. Examples can be a mainframe computer, the server CPU, etc.

The advantages of this type of database are its cost-effectiveness and preservation of data all at one place, thereby increasing data integrity. However, the transactions depend highly on network connectivity.

Distributed databases are the databases of an organization that are distributed at various geographic locations. The database can be either common to all the sites, or it may be specific to that local site only.

Distributed databases are remotely accessed from the respective local site. The reason this type of database was developed was parallel execution of work, division of tasks, thereby reducing the overall time.

End-user database is the database which results out of various operations that the user performs on different databases. These contain information about the end-users of an organization. Such databases are used for deducing summary information about all the transactions in an organization.

These are faster than operational databases, though the latter ones can serve the purpose too. The example of this is spreadsheets, word documents or downloaded files.

External database refers to an online access to an external, privately-owned data. This access is mostly free and available from commercial online services. Hence they are also called 'commercial databases'.

These databases are usually for external users who cannot afford maintaining huge databases. The examples include access to information of wealth regarding a particular individual or his address/phone number through online directories.

When you surf online, you come across a number of web pages that contain images, video clips, links (or hyperlinks as we call it), graphics, media files, etc. This information has to be retrieved or 'called' from somewhere―the hypermedia database.

These comprise a set of interconnected multimedia web pages, wherein the information is stored online and the data can be accessed by several users at a time.

As the name suggests, data warehouse is a large collection of data extracted from various other databases. This data can be used by anyone from a management personnel to an end user. The data is mostly expressed as an edited and screened information.

Depending on the scope of data, databases can be classified into three major types.

General interest databases are the databases that offer information on myriad subjects. The purpose of these databases is to provide all the necessary information to the user on any topic that he searches for. They are mostly used for research work.

Discipline-specific databases are similar to general interest databases, however, information is more streamlined here. This type of databases are useful for professionals in a particular field.

Subject-specific databases are devoted to a particular subject only. They are mostly used for academic purposes. The information is usually in the form of research papers from journals etc.

There are many software languages that help to access various types of databases. Innumerable operations can be performed on the data using these languages. Thus, databases allow you to store, view, access and update data at any point of time.