IBM System R

{{short description|Relational database management system, first implementation of SQL}}

IBM System R is a database system built as a research project at IBM's San Jose Research Laboratory beginning in 1974,

{{cite web

|url=http://www.cs.berkeley.edu/~brewer/cs262/SystemR.pdf

|title=A History and Evaluation of System R

|publisher=IBM

|quote="Phase Zero" of the project, which occurred during 1974 and-most of 1975, involved the development of the SQL user interface}} led by Edgar Codd, to implement his ideas on relational databases.{{Cite interview |interviewer=Burton Grad |title=RDBMS Plenary 1: Early Years |url=https://archive.computerhistory.org/resources/access/text/2013/05/102702562-05-01-acc.pdf |access-date=2025-05-30 |publisher=Computer History Museum |date=2007-06-12}} System R was a seminal project as the first implementation of SQL, which has since become the standard relational data query language. It was also the first system to demonstrate that a relational database could provide good transaction processing performance. Design decisions in System R, as well as some fundamental algorithm choices (such as the dynamic programming algorithm used in query optimization{{citation

| first1 = PG | last1 = Selinger | author1-link = Patricia Selinger

| first2 = MM | last2 = Astrahan

| first3 = Donald D | last3 = Chamberlin | author3-link = Donald D. Chamberlin

| first4 = RA | last4 = Lorie

| first5 = TG | last5 = Price

| year = 1979 | pages = 23–34 | contribution = Access Path Selection in a Relational Database Management System | doi = 10.1145/582095.582099

| title = Proceedings of the 1979 ACM SIGMOD International Conference on Management of Data| isbn = 978-0897910019 | s2cid = 8537523 }}), influenced many later relational systems.

System R's first customer was Pratt & Whitney in 1977.{{Citation | url = http://www.mcjones.org/System_R/SQL_Reunion_95/sqlr95-System.html | last = McJones | first = P | title = System R | contribution = SQL reunion | year = 1995}}. Not running on Unix hurt its popularity.{{r|rdbmsearlyyearsoh20070612}}