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Data Base Task Group
The Data Base Task Group (DBTG) was a working group founded in 1965 (initially named the ''List Processing Task Force'' and later renamed to DBTG in 1967) by the ''Cobol Committee'', formerly ''Programming Language Committee'', of the ''Conference of Data Systems Language'' (CODASYL). The DBTG was chaired by William Olle of RCA. In April 1971, the DBTG published a report containing specifications of a ''Data Manipulation Language'' (DML) and a ''Data Definition Language'' (DDL) for standardization of network database model. The first DBTG proposals had already been published in 1969. The specification was subsequently modified and developed in various committees and published by other reports in 1973 and 1978. The specification is often referred to as the DBTG database model or the CODASYL database model. As well as the data model, many basic concepts of database terminology were introduced by this group, notably the concepts of schema The word schema comes from the Greek word ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CODASYL
CODASYL, the Conference/Committee on Data Systems Languages, was a consortium formed in 1959 to guide the development of a standard programming language that could be used on many computers. This effort led to the development of the programming language COBOL, the CODASYL Data Model, and other technical standards. CODASYL's members were individuals from industry and government involved in data processing activity. Its larger goal was to promote more effective data systems analysis, design, and implementation. The organization published specifications for various languages over the years, handing these over to official standards bodies ( ISO, ANSI, or their predecessors) for formal standardization. History CODASYL is remembered almost entirely for two activities: its work on the development of the COBOL language and its activities in standardizing database interfaces. It also worked on a wide range of other topics, including end-user form interfaces and operating system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Model
The network model is a database model conceived as a flexible way of representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice. The network model was adopted by the CODASYL Data Base Task Group in 1969 and underwent a major update in 1971. It is sometimes known as the CODASYL model for this reason. A number of network database systems became popular on mainframe and minicomputers through the 1970s before being widely replaced by relational databases in the 1980s. Overview While the hierarchical database model structures data as a tree of records, with each record having one parent record and many children, the network model allows each record to have multiple parent and child records, forming a generalized graph structure. This property applies at two levels: the schema is a generalized graph of record types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Schema
The database schema is the structure of a database described in a formal language supported by the database management system (DBMS). The term " schema" refers to the organization of data as a blueprint of how the database is constructed (divided into database tables in the case of relational databases). The formal definition of a database schema is a set of formulas (sentences) called integrity constraints imposed on a database. These integrity constraints ensure compatibility between parts of the schema. All constraints are expressible in the same language. A database can be considered a structure in realization of the database language. The states of a created conceptual schema are transformed into an explicit mapping, the database schema. This describes how real-world entities are modeled in the database. "A database schema specifies, based on the database administrator's knowledge of possible applications, the facts that can enter the database, or those of interest to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Software
Software is a set of programmed instructions stored in the memory of stored-program digital computers for execution by the processor. Software is a recent development in human history, and it is fundamental to the Information Age. Ada Lovelace's programs for Charles Babbage's Analytical Engine in the 19th century is often considered the founder of the discipline, though the mathematician's efforts remained theoretical only, as the technology of Lovelace and Babbage's day proved insufficient to build his computer. Alan Turing is credited with being the first person to come up with a theory for software in 1935, which led to the two academic fields of computer science and software engineering. The first generation of software for early stored-program digital computers in the late 1940s had its instructions written directly in binary code, generally written for mainframe computers. Later, the development of modern programming languages alongside the advancement of the home comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COBOL
COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily used in business, finance, and administrative systems for companies and governments. COBOL is still widely used in applications deployed on mainframe computers, such as large-scale batch and transaction processing jobs. However, due to its declining popularity and the retirement of experienced COBOL programmers, programs are being migrated to new platforms, rewritten in modern languages or replaced with software packages. Most programming in COBOL is now purely to maintain existing applications; however, many large financial institutions were still developing new systems in COBOL as late as 2006. COBOL was designed in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC designed by Grace Hopper. It was created ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
