Relational Database Management Systems
Relational Database Management System (RDBMS) is a DBMS designed specifically for relational databases. Therefore, RDBMSes are a subset of DBMSes.
A relational database refers to a database that stores data in a structured format, using rows and columns. This makes it easy to locate and access specific values within the database. It is "relational" because the values within each table are related to each other. Tables may also be related to other tables. The relational structure makes it possible to run queries across multiple tables at once.
While a relational database describes the type of database an RDMBS manages, the RDBMS refers to the database program itself. It is the software that executes queries on the data, including adding, updating, and searching for values.
An RDBMS may also provide a visual representation of the data. For example, it may display data in a tables like a spreadsheet, allowing you to view and even edit individual values in the table. Some relational database softwareallow you to create forms that can streamline entering, editing, and deleting data.
Most well known DBMS applications fall into the RDBMS category. Examples include Oracle Database, MySQL, Microsoft SQL Server, and IBM DB2. Some of these programs support non-relational databases, but they are primarily used for relational database management.
Examples of non-relational databases include Apache HBase, IBM Domino, and Oracle NoSQL Database. These type of databases are managed by other DMBS programs that support NoSQL, which do not fall into the RDBMS category.
Elements of the relational DBMS that overarch the basic relational database are so intrinsic to operations that it is hard to dissociate the two in practice.
The most basic features of RDBMS are related to create, read, update and delete operations, collectively known as CRUD. They form the foundation of a well-organized system that promotes consistent treatment of data.
The RDBMS typically provides data dictionaries and metadata collections useful in data handling. These programmatically support well-defined data structures and relationships. Data storage management is a common capability of the RDBMS, and this has come to be defined by data objects that range from binary large object (blob) strings to stored procedures. Data objects like this extend the scope of basic relational database operations and can be handled in a variety of ways in different RDBMSes.
The most common means of data access for the RDBMS is via SQL. Its main language components comprise data manipulation language (DML) and data definition language (DDL) statements. Extensions are available for development efforts that pair SQL use with common programming languages, such as COBOL (Common Business-Oriented Language), Java and .NET.
RDBMSes use complex algorithms that support multiple concurrent user access to the database, while maintaining data integrity. Security management, which enforces policy-based access, is yet another overlay service that the RDBMS provides for the basic database as it is used in enterprise settings.
RDBMSes support the work of database administrators (DBAs) who must manage and monitor database activity. Utilities help automate data loading and database backup. RDBMS systems manage log files that track system performance based on selected operational parameters. This enables measurement of database usage, capacity and performance, particularly query performance. RDBMSes provide graphical interfaces that help DBAs visualize database activity.
Relational database management systems are central to key applications, such as banking ledgers, travel reservation systems and online retailing. As RDBMSes have matured, they have achieved increasingly higher levels of query optimization, and they have become key parts of reporting, analytics and data warehousing applications for businesses as well.
RDBMSes are intrinsic to operations of a variety of enterprise applications and are at the center of most master data management (MDM) systems.
F.A.Q. about Relational Database Management Systems
What are the advantages of a Relational Database Management System?
A Relational Database Management System (RDBMS) is a software system that provides access to a relational database. The software system is a collection of software applications that can be used to create, maintain, manage and use the database. A "relational database" is a database structured on the "relational" model. Data are stored and presented in a tabular format, organized in rows and columns with one record per row.
- Data Structure. The table format is simple and easy for database users to understand and use. Relational database management software provide data access using a natural structure and organization of the data. Database queries can search any column for matching entries.
- Multi-User Access. RDBMS database program allow multiple database users to access a database simultaneously. Built-in locking and transactions management functionality allow users to access data as it is being changed, prevents collisions between two users updating the data, and keeps users from accessing partially updated records.
- Privileges. Authorization and privilege control features in an RDBMS allow the database administrator to restrict access to authorized users, and grant privileges to individual users based on the types of database tasks they need to perform. Authorization can be defined based on the remote client IP address in combination with user authorization, restricting access to specific external computer systems.
- Network Access. RDBMSs provide access to the database through a server daemon, a specialized software program that listens for requests on a network, and allows database clients to connect to and use the database. Users do not need to be able to log in to the physical computer system to use the database, providing convenience for the users and a layer of security for the database. Network access allows developers to build desktop tools and Web applications to interact with databases.
- Speed. The relational database model is not the fastest data structure. RDBMS software advantages, such as simplicity, make the slower speed a fair trade-off. Optimizations built into an RDBMS, and the design of the databases, enhance performance, allowing RDBMSs to perform more than fast enough for most applications and data sets. Improvements in technology, increasing processor speeds and decreasing memory and storage costs allow systems administrators to build incredibly fast systems that can overcome any database performance shortcomings.
- Maintenance. RDBMSs feature maintenance utilities that provide database administrators with tools to easily maintain, test, repair and back up the databases housed in the system. Many of the functions can be automated using built-in automation in the RDBMS, or automation tools available on the operating system.
- Language. RDBMSs support a generic language called "Structured Query Language" (SQL). The SQL syntax is simple, and the language uses standard English language keywords and phrasing, making it fairly intuitive and easy to learn. Many RDBMSs add non-SQL, database-specific keywords, functions and features to the SQL language.