DBMS

History of Database Management Systems

Database management systems (DBMSs) have played an outsized role in the history of software development and the creation and growth of the software products industry. Recognizing the major role played by these products, the Annals is publishing two special issues on the subject. This special issue (the first) is focused on the products, companies, and people who designed, programmed, and sold mainframe DBMS software products beginning in the 1960s and 1970s.

Database management systems (DBMSs) have played an outsized role in the history of software development and in the creation and growth of the software products industry. Recognizing the major role played by these products, the Annals is publishing two special issues on the subject. These two issues will be the fourth and fifth sponsored by the Software Industry Special Interest Group of the Computer History Museum (formerly the Software History Center). This issue (the first) is focused on the products, companies, and people who designed, programmed, and sold mainframe DBMS software products beginning in the 1960s and 1970s. The second issue will be devoted to the relational DBMS products, which were developed during the 1970s and came to prominence (and some say dominance) during the 1980s and 1990s.

What was so important about these DBMS products? Why did they have such a major impact on the growth of the software products industry and, more importantly, on the way that almost all major commercial applications were built from the 1970s on? It is a complex story, part of which is told in this issue. Thomas Haigh begins this issue by describing the world prior to DBMSs and some of the early DBMS products. Tim Bergin and Thomas Haigh then examine the database management products that dominated the IBM environment and other major computer platforms in the 1970s and 1980s.

This issue tells the rest of the story through a series of pioneer recollections, principally from people who founded the major DBMS companies or were heavily involved in the growth and development of these products and companies. These eight recollections cover the principal DBMS software products for IBM mainframe computers. 1 IBM itself was a significant player in this marketplace with its IMS product, but all the other products were produced and marketed by independent software companies. Many historians and industry analysts believe that these products and these companies formed the foundation on which the mainframe software products industry was built.




The significance of DBMSs

In some sense, these DBMSs, with their accompanying data communications (or online transaction processing) systems, enabled users in all industries to construct both online and batch applications in a far more timely and cost effective manner. These database and data communications systems became the foundation for building many (some say most) of the core applications in every industry and government agency, and they became the engines that drove the sale of mainframe computers during the 1970s and afterward.

The following list supplies just some of the reasons why industry analysts and historians consider DBMS software products so important from both a technological and business standpoint:

• They provided an efficient way to program complex applications without the cost of rewriting the data access and retrieval functions for each application.
  
• They provided a relatively simple, standard way to share data among multiple applications and multiple users.
  
• They created specialized user-oriented languages.
  
• They provided standard interfaces for the data communications programs so that the online transaction processing applications could be efficiently built, tested, and maintained (both in time and cost).
  
• They managed the databases on various random- and sequential-access devices without the application programmer having to think about the differences.
  
• They provided portability; in many cases, they enabled customers to move their applications from one manufacturer's platform to another or from one operating system to another with relative ease.
  
• The companies marketing these products became the largest independent software products companies and were the first to go public in the late 1970s and early 1980s.
  
• They effectively sold a tremendous amount of hardware for IBM, IBM's mainframe competitors, many minicomputer manufacturers, and the independent storage device and terminal companies.
  
  

This issue only minimally refers to other related areas that some feel should be considered a vital part of the DBMS story. These DBMS products were preceded by a number of report writers, which used stored information to produce reports in the layout and form desired by the user. These report writers pioneered the definition-based applications approach versus a procedural programming approach. This category included IBM's Fargo and Report Program Generator (RPG), Informatics' Mark IV, Pansophic's Easytrieve, Cullinane's Culprit, Bill Newcomer's Dylakor, and many others. As the Bergin and Haigh article notes, almost every DBMS had its own report writer or could interface to one of the available products.

A second area that was of at least equal significance to report writers were the fourth generation languages (4GLs), which had a user-specified layout mapping the inputs and transformations to the outputs, but each of these products had its own proprietary database within the program. These software products were successful over many years and are still in use today. Ramis, Focus, and Nomad were among the early leaders, and they were followed by many more such application development software products that were introduced in the 1980s. These gave run-of-the-mill users the ability to specify and "program" their own applications without having to wait for the professional programmers.




Database management system type and characteristics

Database management is an integral part of every company that is organized and managed the data is found. Database server and desktop database are two types of database management systems.

Although primarily a multi-user database server applications and data consistency is the most reliable. It is more expensive than desktop database and operates on a high performance server.

Choose a web site database design before the end blindly in the analysis and research required, must dip.Also, many times for server-based database needs are emerging.

Database that would be best to analyze the needs of companies, some points should be clarified.Database and using it will be in charge of the relevant authority should be known. In addition, data and IT resources that will assist the person responsible for maintenance should be aware. Make sure the hardware available and the budget to buy hardware.

Important issues that you evaluate the implementation of specific database management system can start after cleaning.Requirements for simple desktop database like Microsoft Access is the right choice. It’s cheap and a simple data storage and manipulation facilities offers. As the name suggests, it runs on a personal computer and is best for them. Microsoft Access, Lotus, FileMaker Pro, in addition, FoxPro and contradiction are some popular desktop database software.

Oracle, Microsoft SQL Server and IBM DB 2 is a popular database servers. The amount of data effectively manage large enough to provide expertise, and users can access to data when needed.

A structure and a solid foundation for future corporate success plan for providing such a database design. If you plan accordingly to improve performance and future development can.




Component Database Management Systems

OLE DB uses the Component Object Model (COM) infrastructure, which reduces unnecessary duplication of services and provides a higher degree of interoperability, not only among diverse information sources but also among existing programming environments and tools. Indeed, OLE DB is the way to access data in a COM environment. OLE DB defines an open, extensible collection of COM interfaces that encapsulate reusable portions of DBMS functionality. These interfaces define the boundaries of DBMS components, such as row containers, query processors, and transaction coordinators, that provide uniform transactional access to diverse information sources. Such components factor a DBMS into a set of cooperating components that consume and produce data through a uniform set of interfaces.

The OLE DB functional areas include data access and updates (rowsets), query processing, catalog information, notifications, transactions, security, and remote data access. By defining a uniform set of interfaces to access data, OLE DB components not only contribute to uniform data access among diverse information sources but also help reduce the application's complexity by enabling developers to use only the DBMS functionality they need. The following illustration shows how an application can employ OLE DB interfaces to initiate actions by a query processor to access different data structures.

A component DBMS architecture using OLE DB interfaces

The sections that follow go into these concepts in detail.




Components of a DBMS

Database Management System (DBMS)

DBMSs are the technology tools that directly support managing organizational data. With a DBMS you can create a database including its logical structure and constraints, you can manipulate the data and information it contains, or you can directly create a simple database application or reporting tool. Human administrators, through a user interface, perform certain tasks with the tool such as creating a database, converting an existing database, or archiving a large and growing database. Business applications, which perform the higher level tasks of managing business processes, interact with end users and other applications and, to store and manage data, rely on and directly operate their own underlying database through a standard programming interface like ODBC.

The following diagram illustrates the five components of a DBMS.

Database Engine:

The Database Engine is the core service for storing, processing, and securing data. The Database Engine provides controlled access and rapid transaction processing to meet the requirements of the most demanding data consuming applications within your enterprise.Use the Database Engine to create relational databases for online transaction processing or online analytical processing data. This includes creating tables for storing data, and database objects such as indexes, views, and stored procedures for viewing, managing, and securing data. You can use SQL Server Management Studio to manage the database objects, and SQL Server Profiler for capturing server events.

Data dictionary:

A data dictionary is a reserved space within a database which is used to store information about the database itself. A data dictionary is a set of table and views which can only be read and never altered.Most data dictionaries contain different information about the data used in the enterprise. In terms of the database representation of the data, the data table defines all schema objects including views, tables, clusters, indexes, sequences, synonyms, procedures, packages, functions, triggers and many more. This will ensure that all these things follow one standard defined in the dictionary. The data dictionary also defines how much space has been allocated for and / or currently in used by all the schema objects.A data dictionary is used when finding information about users, objects, schema and storage structures. Every time a data definition language (DDL) statement is issued, the data dictionary becomes modified.

A data dictionary may contain information such as:

• Database design information
  
• Stored SQL procedures
  
• User permissions
  
• User statistics
  
• Database process information
  
• Database growth statistics
  
• Database performance statistics
  
  

Query Processor :

A relational database consists of many parts, but at its heart are two major components: the storage engine and the query processor. The storage engine writes data to and reads data from the disk. It manages records, controls concurrency, and maintains log files.The query processor accepts SQL syntax, selects a plan for executing the syntax, and then executes the chosen plan. The user or program interacts with the query processor, and the query processor in turn interacts with the storage engine. The query processor isolates the user from the details of execution: The user specifies the result, and the query processor determines how this result is obtained. The query processor components include

• DDL interpreter
  
• DML compiler
  
• Query evaluation engine
  
  

Report writer:

Also called a report generator, a program, usually part of a database management system, that extracts information from one or more files and presents the information in a specified format. Most report writers allow you to select records that meet certain conditions and to display selected fields in rows and columns. You can also format data into pie charts, bar charts, and other diagrams. Once you have created a format for a report, you can save the format specifications in a file and continue reusing it for new data.