Английская Википедия:IBM Peterlee Relational Test Vehicle
PRTV (Peterlee Relational Test Vehicle) was the world's first relational database management system that could handle significant data volumes.
It was a relational query system with powerful query facilities, but very limited update facility and no simultaneous multiuser facility. PRTV was a successor from the very first relational implementation, IS1.
Features
PRTV included several firsts in the relational database area:
- implemented relational optimizer[1]
- implemented cost-based relational optimizer[2]
- handle tables of 1,000 rows up to 10,000,000 rows[3]
- user-defined functions (UDFs) within an RDB (also a large suite of built-in functions such as trigonometric and statistical)[4]
- geographic information system based on an RDB (using UDFs such as point-in-polygon).[5]
PRTV was based on a relational algebra, Information Systems Base Language (ISBL) and followed the relational model very strictly. Even features such as user-defined functions were formalized within that model.[6] The PRTV team also introduced surrogates to the relational model[4] to help formalize relational update operations; and a formalisation for updating through views.[7] However neither of these was implemented within PRTV. PRTV emphatically did not implement NULL values, because this conception was introduced only in 1979.[8]
PRTV was itself never available as a product, but the Urban Management System[9] built on it was available as a limited IBM product.
Implementation
PRTV was written in a mixture of languages. The higher layers were written in MP/3 and PL/I,[2]Шаблон:Rp whereas the lower layers were written in PL/I and System/370 assembler language.[2]Шаблон:Rp MP/3 was a macro processing language developed at Peterlee from 1973 onwards, similar to ML/I or TRAC.[10] PRTV ran on System/370 IBM mainframes.[2]Шаблон:Rp
References