A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database (a large set of structured data), and run operations on the data requested by numerous clients. Typical examples of DBMS use include accounting, human resources and customer support systems. Originally found only in large organizations with the computer hardware needed to support large data sets, DBMSs have more recently emerged as a fairly standard part of any company back office. A computer program or software program (usually abbreviated to a program) is a step-by-step list of instructions written for a particular computer architecture in a particular computer programming language. ... A database is an organized collection of data. ... Data is the plural of datum. ... Accountancy (British English) or accounting (American English) is the process of maintaining, auditing, and processing financial information for business purposes. ... Human resources has at least two meanings depending on context. ... A computer is a machine capable of undergoing complex calculations. ... A back office is a part of most corporations where tasks dedicated to running the company itself take place. ...

DBMS's are found at the heart of most database applications. Sometimes DBMSs are built around a private multitasking kernel with built-in networking support although nowadays these functions are left to the operating system. A database is an information set with a regular structure. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is... In computer science, the kernel is the fundamental part of an operating system. ... A computer network is a system for communication between computers. ... In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ...

Terminology

A database management system (DBMS) is a system, usually automated and computerized, for the management of any collection of compatible, and ideally normalized, data. This article is in need of attention from an expert on the subject. ...

A database application is computer software written to manage the data of a particular application or problem. A database is an information set with a regular structure. ... A screenshot of computer software in action. ...

History

Databases have been in use since the earliest days of electronic computing, but the vast majority of these were custom programs written to access custom databases. Unlike modern systems which can be applied to widely different databases and needs, these systems were tightly linked to the database in order to gain speed at the expense of flexibility.

Navigational DBMS

As computers grew in capability, this tradeoff became increasingly unnecessary and a number of general-purpose database systems emerged; by the mid-1960s there were a number of such systems in commercial use. Interest in a standard began to grow, and Charles Bachman, author of one such product, IDS, founded the Database Task Group within CODASYL, the group responsible for the creation and standardization of COBOL. In 1971 they delivered their standard, which generally became known as the Codasyl approach, and soon there were a number of commercial products based on it available. The 1960s decade refers to the years from 1960 to 1969, inclusive. ... Charles W. Bachman is a prominent computer scientist, particularly in the area of databases. ... Integrated Data Store (IDS) is a network database largely used by industry for its performance. ... CODASYL (often spelt Codasyl) is an acronym for COnference on DAta SYstems Languages. This was a IT industry consortium formed in 1959 to guide the development of a standard programming language that could be used on many computers. ... COBOL is a third-generation programming language. ... 1971 (MCMLXXI) is a common year starting on Friday (click for link to calendar). ...

The Codasyl approach was based on the "manual" navigation of a linked dataset which was formed into a large network. When the database was first opened, the program was handed back a link to the first record in the database, which also contained pointers to other pieces of data. To find any particular record the programmer had to step through these pointers one at a time until the required record was returned. Simple queries like "find all the people in Sweden" required the program to walk the entire data set and collect the matching results. There was, essentially, no concept of "find" or "search". This might sound like a serious limitation today, but in an era when the data was most often stored on magnetic tape such operations were too expensive to contemplate anyway. In computer science, a database record is a description of a single item as stored in a database. ... In computer science, a pointer is a programming language datatype whose value refers directly to (points to) another value stored elsewhere in the computer memory using its address. ... Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ...

IBM also had their own DBMS system in 1968, known as IMS. IMS was a development of software written for the Apollo program on the System/360. IMS was generally similar in concept to Codasyl, but used a strict hierarchy for its model of data navigation instead of Codasyl's network model. International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, New York, USA. The company manufactures and sells computer hardware, software, and services. ... Information Management System (IMS) is a joint hierarchical database and information management system. ... Apollo Program insignia Project Apollo was a series of human spaceflight missions undertaken by the United States of America using the Apollo spacecraft and Saturn launch vehicle, conducted during the years 1961–1972. ... The IBM System/360 (S/360) is a mainframe computer system family announced by International Business Machines on April 7, 1964. ...

Both concepts later became known as navigational databases due to the way data was accessed, and Bachman's 1973 Turing Award award presentation was The Programmer as Navigator. IMS is classified as a hierarchical database. IDS and IDMS (both CODASYL databases) as well as CINCOMs TOTAL database are classified as network databases. Navigational databases incorporate both the network model and hierarchical model of database interfaces. ... The A.M. Turing Award is given annually by the Association for Computing Machinery to a person selected for contributions of a technical nature made to the computing community. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... IDMS (Integrated Database Management System) is a (network) CODASYL database management system first developed at B.F. Goodrich and later marketed by Cullinane Database Systems (renamed Cullinet in 1983). ... The network model is a database model conceived as a more flexible alternative to the hierarchical model. ...

Relational DBMS

Edgar Codd worked at IBM in San Jose, California, in one of their offshoot offices that was primarily involved in the development of hard disk systems. He was unhappy with the navigational model of the Codasyl approach, notably the lack of a "search" facility which was becoming increasingly useful when the database was stored on disk instead of tape. In 1970 he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking A Relational Model of Data for Large Shared Data Banks. A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users. ... Edgar F. Ted Codd (August 23, 1923 - April 18, 2003) was a British computer scientist who made seminal contributions to the theory of relational databases. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, New York, USA. The company manufactures and sells computer hardware, software, and services. ... Nickname: Capital of Silicon Valley Motto: Official website: http://www. ... Typical hard drives of the mid-1990s. ...

In this paper he described a new system for storing and working with large databases. Instead of records being stored in some sort of linked list of free-form records as in Codasyl, Codd's idea was to use a "table" of fixed-length records. A linked-list system would be very inefficient when storing "sparse" databases where some of the data for any one record could be left empty. The relational model solved this by splitting the data into a series of tables, with optional elements being moved out of the main table to where they would take up room only if needed. In computer science, a linked list is one of the fundamental data structures used in computer programming. ... In a relational database (RDB), a table is a set of data elements (cells) that is organized, defined and stored as horizontal rows (records) and vertical columns (fields) where each item can be uniquely identified by a label or key or by it’s position in relation to other items. ...

In the relational model, related records are linked together with a "key".

For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach all of these data would be placed in a single record, and unused items would simply not be placed in the database. In the relational approach, the data would be split into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided. Relational Model for databases, highlighting the Key. ... Relational Model for databases, highlighting the Key. ...

Linking the information back together is the key to this system. In the relational model some bit of information was used as a "key", uniquely defining a particular record. When information was being collected about a user, information stored in the optional (or related) tables would be found by searching for this key. For instance, if the login name of a user is unique, addresses and phone numbers for that user would be recorded with the login name as its key. This "re-linking" of related data back into a single collection is something that traditional computer languages are not designed for. The word key has several uses: Look up Key on Wiktionary, the free dictionary // Instrument or Tool A key (instrument) comprises a moving part of a musical instrument. ... Look up Collection on Wiktionary, the free dictionary In common usage, a collection is any group of items that has one or more properties in common, usually brought together for some specific purpose. ...

Just as the navigational approach would require programs to loop in order to collect records, the relational approach would require loops to collect information about any one record. Codd's solution to the necessary looping was a set-oriented language, a suggestion that would later spawn the ubiquitous SQL. Using a branch of mathematics known as tuple calculus, he demonstrated that such a system could support all the operations of normal databases (inserting, updating etc.) as well as providing a simple system for finding and returning sets of data in a single operation. SQL (commonly expanded to Structured Query Language - see History for the terms derivation) is the most popular computer language used to create, modify and retrieve data from relational database management systems. ... This article may be too technical for most readers to understand. ...

Codd's paper was picked up by two people at Berkeley, Eugene Wong and Michael Stonebraker. They started a project known as INGRES using funding that had already been allocated for a geographical database project, using student programmers to produce code. Beginning in 1973, INGRES delivered its first test products which were generally ready for widespread use in 1979. During this time a number of people had moved "through" the group — perhaps as many as 30 people worked on the project, about five at a time. INGRES was similar to System R in a number of ways, including the use of a "language" for data access, known as QUEL — QUEL was in fact relational, having been based on Codd's own Alpha language, but has since been corrupted to follow SQL, thus violating much the same concepts of the relational model as SQL itself. Michael Stonebraker is a computer scientist specializing in database research and development. ... This article is about a relational database system. ... System R is a database system built as a research project at IBM San Jose Research (now IBM Almaden Research Center) in the 1970s. ... QUEL is a relational database access language, similar in most ways to SQL, but somewhat better arranged and easier to use. ...

IBM itself did only one test implementation of the relational model, PRTV, and a production one, Business System 12, both now discontinued. Honeywell did MRDS for Multics, and now there are two new implementations: Alphora Dataphor and Rel. All other DBMS implementations usually called relational are actually SQL DBMSs. PRTV (Peterlee Relational Test Vehicle [1,2]) was the worlds first relational database management system that could handle significant data volumes -- it was really a relational query system as it had very powerful query facilities, but very limited update facility and no simultaneous multiuser facility. ... Business System 12, or simply BS12, was one of was the first fully relational database management systems, designed and implemented by IBMs UK Bureau Service subsidiary. ... Honeywell NYSE: HON is a major American multinational corporation that produces electronic control systems and automation equipment. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... A semantic link is a typed link where the element itself provides meaningful information about the link (semantics). ...

SQL DBMS

IBM started working on a prototype system loosely based on Codd's concepts as System R in the early 1970s — unfortunately System R was conceived as a way of proving Codd's ideas unimplementable, and thus the project was delivered to a group of programmers who weren't under Codd's supervision, never understood his ideas fully and ended up violating several fundamentals of the relational model. The first "quickie" version was ready in 1974/5, and work then started on multi-table systems in which the data could be broken down so that all of the data for a record (much of which is often optional) didn't have to be stored in a single large "chunk". Subsequent multi-user versions were tested by customers in 1978 and 79, by which time a standardized computer language, SQL, had been added. Codd's ideas were establishing themselves as both workable and superior to Codasyl, pushing IBM to develop a true production version of System R, known as SQL/DS, and, later, Database 2 (DB2). System R is a database system built as a research project at IBM San Jose Research (now IBM Almaden Research Center) in the 1970s. ... 1974 (MCMLXXIV) is a common year starting on Tuesday (click on link for calendar). ... 1978 (MCMLXXVIII) was a common year starting on Sunday (the link is to a full 1978 calendar). ... A computer language is a language used by, or in association with, computers. ... SQL (commonly expanded to Structured Query Language - see History for the terms derivation) is the most popular computer language used to create, modify and retrieve data from relational database management systems. ... DB2® is IBMs family of information management software products. ...

Many of the people involved with INGRES became convinced of the future commercial success of such systems, and formed their own companies to commercialize the work but with an SQL interface. Sybase, Informix, NonStop SQL and eventually Ingres itself were all being sold as offshoots to the original INGRES product in the 1980s. Even Microsoft SQL Server is actually a re-built version of Sybase, and thus, INGRES. Only Larry Ellison's Oracle started from a different chain, based on IBM's papers on System R by beating them to market when the first version was released in 1978. Sybase Inc. ... Informix is a family of relational database management system products from IBM, acquired in 2001 from a company (also called Informix or Informix Software) which dates its origins back to 1980. ... NonStop SQL is a relational database product originally produced at Tandem Computers using the pioneering Ingres source code from University of California, Berkeley. ... This article is about a relational database system. ... Microsoft SQL Server is a relational database management system produced by Microsoft. ... Lawrence Joseph Ellison (born August 17, 1944) is the co-founder and CEO of Oracle Corporation, a major database software firm. ... Oracle Corporation (NASDAQ: ORCL), one of the major companies developing database management systems, tools for database development, and enterprise resource planning software, customer relationship management software (CRM) and supply chain planning (SCM) software dates from 1977 and has offices in more than 145 countries around the world. ...

Stonebraker went on to apply the lessons from INGRES to develop a new database, Postgres, now known as PostgreSQL. PostgreSQL is now one of the most widely used databases in the world, primarily for global mission critical applications (the .org and .info domain name registries use it as their primary data store, as do many large companies and financial institutions). PostgreSQL is a free object-relational database server (database management system), released under a flexible BSD-style license. ...

In Sweden Codd's paper was also read, Mimer SQL was developed from the mid-70s at Uppsala University, and in 1984 this project was consolidated into an independent enterprise. In the early 1980s Mimer introduced transaction handling for high robustness in applications, an idea that was subsequently implemented on most other DBMSs. Mimer SQL is an SQL-based relational database management system from the Swedish company Mimer Information Technology AB (formerly: Upright Database Technology AB), which has been developed and produced since the 1970s. ... Uppsala University (Swedish Uppsala universitet) is a public university in Uppsala, Sweden. ...

Object-oriented DBMS

Multidimensional DBMS did have one lasting impact on the market: they led directly to the development of object database systems. Based on the same general structure and concepts as the multidimensional systems, these new systems allowed the user to store objects directly in the database. That is, the programming constructs being used in the object oriented (OO) programming world could be used directly in the database, instead of first being converted to some other format. It has been suggested that this article or section be merged with DBMS. (Discuss) An object database is a database based on object-oriented concepts as opposed to tuples or records from a relational database or Relational Database Management System. ... An object database is a database in which information is represented in the form of objects. ... Object-oriented programming (OOP) is a computer programming paradigm in which a software system is modeled as a set of objects that interact with each other. ...

This could happen because of the multidimensional system's concepts of ownership. In an OO program a particular object will typically contain others; for example, the object representing Bob may contain a reference to a separate object referring to Bob's home address. Adding support for various OO languages and polymorphism re-created the multidimensional systems as object databases, which continue to serve a niche today. Ownership is the state or fact of exclusive possession or control of some thing, which may be an object or some kind of property. ... In computer science, polymorphism means allowing a single definition to be used with different types of data (specifically, different classes of objects). ...

Description

A DBMS can be an extremely complex set of software programs that controls the organization, storage and retrieval of data (fields, records and files) in a database. The basic functionalities that a DBMS must provide are: An organization (U.S. spelling) or organisation (U.K. spelling) is a formal group of people with one or more shared goals. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A database is an organized collection of data. ...

1. A modeling language to define the schema of each database hosted in the DBMS, according to the DBMS data model.
   • The three most common organizations are the hierarchical, network and relational models. A database management system may provide one, two or all three methods. Inverted lists and other methods are also used. The most suitable structure depends on the application and on the transaction rate and the number of inquiries that will be made.
     The dominant model in use today is the ad hoc one embedded in SQL, a corruption of the relational model by violating several of its fundamental principles. Many DBMSs also support the Open Database Connectivity API that supports a standard way for programmers to access the DBMS.
2. Data structures optimized to deal with big amounts of data recorded to a permanent data storage device, which are very slow compared to the primary storage (volatile main memory).
3. A database query language and report writer to allow users to interactively interrogate the database, analyse its data and update it according to the users privileges on data.
   • It also controls the security of the database.
   • Data security prevents unauthorised users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called subschemas (pronounced "sub-skeema"). For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data.
   • If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases. However, it may not leave an audit trail of actions or provide the kinds of controls necessary in a multi-user organisation. These controls are only available when a set of application programs are customised for each data entry and updating function.
4. A transaction mechanism, that ideally would guarantee the ACID properties, in order to ensure data integrity despite of concurrent user access (concurrency control) and faults (fault tolerance).
   • It also controls the integrity of the database.
   • The DBMS can maintain the integrity of the database by not allowing more than one user to update the same record at the same time. The DBMS can keep duplicate records out of the database; for example, no two customers with the same customer numbers (key fields) can be entered into the database. See ACID properties for more information (Reduncdancy avoidance).

The DBMS accepts requests for data from the application program and instructs the operating system to transfer the appropriate data. In information system design, data modeling is the analysis and design of the information in the system, concentrating on the logical entities and the logical dependencies between these entities. ... The word schema comes from the Greek word σχήμα (skhēma) that means shape or more generally plan. ... A database is an organized collection of data. ... A data model is a model that describes in an abstract way how data is represented in a business organization, an information system or a database management system. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The network model is a database model conceived as a more flexible alternative to the hierarchical model. ... It has been suggested that Relational database be merged into this article or section. ... Open Database Connectivity (ODBC) is a standard software API specification for using database management systems (DBMS). ... API with 3 clients, using the Unified Modeling Language notation An application programming interface (API) is the interface that a computer system or application provides in order to allow requests for service to be made of it by other computer programs, and/or to allow data to be exchanged between... A programmer or software developer is someone who programs computers, i. ... A binary tree, a simple type of branching linked data structure. ... Digital permanence addresses the history and development of digital storage techniques specifically quantifying the expected lifetime of data stored on various digital media and the factors which influence the permanence of digital data. ... In computing, a data storage device—as the name implies—is a device for storing data. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... It has been suggested that this article or section be merged with Physical memory. ... Database query languages are like programming languages. ... In computing, privilege is defined as the delegation of authority over a system. ... Security is being free from danger. ... Data security is the means of ensuring that data is kept safe from corruption and that access to it is suitably controlled. ... A database transaction is a unit of interaction with a database management system or similar system that is treated in a coherent and reliable way independent of other transactions that must be either entirely completed or aborted. ... An acid (from Arabic Azait meaning oil, often represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. ... In telecommunication, the term data integrity has the following meanings: The condition that exists when data is unchanged from its source and has not been accidentally or maliciously modified, altered, or destroyed. ... In computer science, concurrency is concerned with the study and design of systems which consist of computations that execute overlapped in time (including running in parallel), and which may permit the sharing of common resources between those overlapped computations. ... In computer science -- more specifically, in the field of databases -- concurrency control is a method used to ensure that database transactions are executed in a safe manner (i. ... In computer science, Fault-tolerance is the property of a computer system to continue operation at an acceptable quality, despite the unexpected occurrence of hardware or software failures. ... Integrity comprises the personal inner sense of wholeness deriving from honesty and consistent uprightness of character. ... An acid (from Arabic Azait meaning oil, often represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. ... In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ...

When a DBMS is used, information systems can be changed much more easily as the organization's information requirements change. New categories of data can be added to the database without disruption to the existing system. The term information system has the following meanings: 1. ...

Organizations may use one kind of DBMS for daily transaction processing and then move the detail onto another computer that uses another DBMS better suited for random inquiries and analysis. Overall systems design decisions are performed by data administrators and systems analysts. Detailed database design is performed by database administrators.

Database servers are specially designed computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with RAID disk arrays used for stable storage. Connected to one or more servers via a high-speed channel, hardware database accelerators are also used in large volume transaction processing environments. A database server is a computer program that provides database services to other computer programs or computers, as defined by the client-server model; the term may also refer to a computer dedicated to running such a program. ... Multiprocessing is traditionally known as the use of multiple concurrent processes in a system as opposed to a single process at any one instant. ... In computing, a redundant array of independent disks, also known as redundant array of inexpensive disks (commonly abbreviated RAID) is a system of using multiple hard drives for sharing or replicating data among the drives. ...

See also

• Data warehouse
• Directory service
• Distributed Database Management System
• Navigational database management system
• Hierarchical database management system
• Network database management system
• Object-oriented database management system (OODBMS)
• Relational database management system (RDBMS)
• Object-relational database management system (ORDBMS)
• SQL is a language for database management.