Editing CODASYL (section)

== History ==
{{More citations needed section|date=May 2023}}
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 [[User interface|end-user form interfaces]] and [[operating system]] control languages, but these projects had little lasting impact.

The remainder of this section is concerned with CODASYL's database activities.

In 1965 CODASYL formed a List Processing Task Force. This group was chartered to develop COBOL language extensions for processing collections of records; the name arose because [[Charles Bachman]]'s [[Integrated Data Store|IDS]] system (which was the main technical input to the project) managed relationships between records using chains of pointers. In 1967 the group renamed itself the [[Data Base Task Group]] (DBTG), and its first report in January 1968 was entitled ''COBOL extensions to handle data bases''.

[[File:CodasylB.png|thumb|360px|The "set", the basic structure of the CODASYL database model. A set consists of one owner record and n member records (these are labeled as "parent" and "child" in the diagram, but the CODASYL terminology is "owner" and "member"). In the above example, we were looking at a basic set which embodies a 1:N (Owner:Member) relationship.<ref>{{cite book |last = Waldner  |first = Jean-Baptiste  |authorlink = Jean-Baptiste Waldner  |title = CIM: Principles of Computer Integrated Manufacturing |publisher = [[John Wiley & Sons Ltd]] |place = Chichester|year = 1992| page = 47 |isbn = 0-471-93450-X}}</ref>]] In October 1969 the DBTG published its first language specifications for the [[network model|network database model]] which became generally known as the CODASYL Data Model. This specification in fact defined several separate languages: a [[data definition language]] (DDL) to define the [[logical schema|schema]] of the database, another DDL to create one or more subschemas defining application views of the database; and a [[data manipulation language]] (DML) defining verbs for embedding in the COBOL programming language to request and update data in the database. Although the work was focused on COBOL, the idea of a host-language independent database was starting to emerge, prompted by [[IBM]]'s advocacy of [[PL/I]] as a COBOL replacement.

In 1971, largely in response to the need for programming language independence, the work was reorganized: development of the Data Description Language was continued by the [[Data Description Language Committee]], while the COBOL DML was taken over by the COBOL language committee. With hindsight, this split had unfortunate consequences. The two groups never quite managed to synchronize their specifications, leaving vendors to patch up the differences. The inevitable consequence was a lack of interoperability among implementations.

A number of vendors implemented database products conforming (roughly) to the DBTG specifications: the best-known implementations were [[Honeywell]]'s&mdash;originally [[General Electric]]'s&mdash;Integrated Data Store (IDS/2), HP's [[IMAGE (database)|IMAGE]], Cullinet's Integrated Database Management System [[IDMS]], [[International Computers Limited|ICL's]] 2900 IDMS (derived from Cullinet's product), [[Univac]]'s DMS-1100, and [[Digital Equipment Corporation]]'s DBMS for [[OpenVMS|VMS]] (later known as [[Oracle (corporation)|Oracle]] Codasyl DBMS). [[Cullinet]], originally known as Cullinane Database Systems, obtained the technology from [[Goodrich Corporation|B.F. Goodrich]].  Cullinet was eventually sold to [[CA, Inc.|Computer Associates]], which as of 2007 still sells and supports a version of IDMS.

[[ANSI]] and [[International Organization for Standardization|ISO]] adopted the CODASYL database specifications under the name Network Database Language (NDL), with work taking place within the same working group (X3H2) as [[SQL]] standardization. An ISO standard for NDL was ratified as ISO 8907:1987,<ref>{{Cite web|url=http://www.iso.org/iso/catalogue_detail.htm?csnumber=16434|title = Iso 8907:1987}}</ref> but, as it never had any practical effect on implementations, it was formally withdrawn in 1998.

Some of the CODASYL committees continue their work today, but CODASYL itself no longer exists.  The records of CODASYL were donated to the [[Charles Babbage Institute]].<ref>See a finding guide to [http://purl.umn.edu/40644 Conference on Data Systems Languages Records, 1959-1987]. [[Charles Babbage Institute]], University of Minnesota</ref>  CBI also hold the archival records for American National Standards Institute [http://purl.umn.edu/40837 X3H2 records].

Interest in CODASYL gradually faded due to growing interest in [[relational database]]s beginning in the early 1980s.