What Is a Database Management System (DBMS)?

A database management system (DBMS) is the software that allows a computer to store, retrieve, add, delete, and modify data. A DBMS manages all primary aspects of a database, including managing data manipulation, such as user authentication, as well as inserting or extracting data. A DBMS defines what's called the data schema, or the structure in which the data is stored.

Tools we all use every day require DBMSs behind the scenes.

This includes ATMs, flight reservation systems, retail inventory systems, and library catalogs, for instance.

Relational database management systems (RDBMS) implement the relational model of tables and relationships.

Background on Database Management Systems

The term DBMS has been around since the 1960s, when IBM developed the first DBMS model called an Information Management System (IMS), in which data were stored in a computer in a hierarchical tree structure. Individual pieces of data were connected only between parent and child records.

The next generation of databases were network DBMS systems, which tried to solve some of the limitations of the hierarchical design by incorporating a one-to-many relationship between data. This took us into the 1970s when the relational database model was established by IBM's Edgar F. Codd, literally the father of the modern relational DBMS that we know today.

Features of the Modern Relational DBMS

Relational database management systems (RDBMS) implement the relational model of tables and relationships. The primary design challenge of today's relational DBMSs is to maintain data integrity, which protects the accuracy and consistency of the data. This is ensured through a series of constraints and rules on the data to avoid duplication or data loss.

DBMSs also control access to the database through authorization, which can be implemented at various levels. For example, managers or administrators might have access to data that is not visible to other employees, or they may have the authorization to edit the data while some users can only view it.

Most DBMSs use the structured query language SQL, which provides a way to interact with the database. In fact, even if the database provides a graphical interface that allows users to easily view, select, edit, or otherwise manipulate the data, it is SQL that performs these tasks in the background.

Examples of DBMSs

Today, many commercial and open-source DBMSs are available. In fact, choosing which database you need is a complex task. The high-end relational DBMS market is dominated by Oracle, Microsoft SQL Server, and IBM DB2, all credible choices for complex and large data systems. For small organizations or home use, popular DBMSs are Microsoft Access and FileMaker Pro.

More recently, other nonrelational DBMSs have grown in popularity. These are the NoSQL flavor, in which the rigidly defined schema of the RDBMs is replaced by a more flexible structure. These are useful for storing and working with very large data sets comprising a wide range of data types.

Major players in this space include MongoDB, Cassandra, HBase, Redis, and CouchDB.