Editing Database (section)

===1960s, navigational DBMS===
{{Further|Navigational database}}
[[File:CodasylB.png|thumb|upright=1.15|Basic structure of navigational [[CODASYL]] database model]]

The introduction of the term ''database'' coincided with the availability of direct-access storage (disks and drums) from the mid-1960s onwards. The term represented a contrast with the tape-based systems of the past, allowing shared interactive use rather than daily [[batch processing]]. The [[Oxford English Dictionary]] cites a 1962 report by the [[System Development Corporation]] of California as the first to use the term "data-base" in a specific technical sense.<ref>{{cite web|title=database, n|url=http://www.oed.com/view/Entry/47411|work=OED Online|publisher=Oxford University Press|access-date=July 12, 2013|date=June 2013}} {{subscription required|s}}</ref>

As computers grew in speed and capability, a number of general-purpose database systems emerged; by the mid-1960s a number of such systems had come into commercial use. Interest in a standard began to grow, and [[Charles Bachman]], author of one such product, the [[Integrated Data Store]] (IDS), founded the [[Data Base Task Group|Database Task Group]] within [[CODASYL]], the group responsible for the creation and standardization of [[COBOL]]. In 1971, the Database Task Group delivered their standard, which generally became known as the ''CODASYL approach'', and soon a number of commercial products based on this approach entered the market.

The CODASYL approach offered applications the ability to navigate around a linked data set which was formed into a large network. Applications could find records by one of three methods:
#Use of a primary key (known as a CALC key, typically implemented by [[Hash function|hashing]])
#Navigating relationships (called ''sets'') from one record to another
#Scanning all the records in a sequential order

Later systems added [[B-tree]]s to provide alternate access paths. Many CODASYL databases also added a declarative query language for end users (as distinct from the navigational [[API]]). However, CODASYL databases were complex and required significant training and effort to produce useful applications.

[[IBM]] also had its own DBMS in 1966, known as [[IBM Information Management System|Information Management System]] (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. Both concepts later became known as navigational databases due to the way data was accessed: the term was popularized by Bachman's 1973 [[Turing Award]] presentation ''The Programmer as Navigator''. IMS is classified by IBM as a [[hierarchical database]]. IDMS and [[Cincom Systems]]' [[Cincom Systems#1970s|TOTAL]] databases are classified as network databases. IMS remains in use {{as of | 2014 | lc = on}}.<ref>{{cite web|last=IBM Corporation|title=IBM Information Management System (IMS) 13 Transaction and Database Servers delivers high performance and low total cost of ownership|url=http://www-01.ibm.com/common/ssi/cgi-bin/ssialias?subtype=ca&infotype=an&appname=iSource&supplier=897&letternum=ENUS213-381|access-date=Feb 20, 2014|date=October 2013}}</ref>