== Relevant Papers ==
  * [[http://www.ifi.uzh.ch/dbtg/fileadmin/storage/Glavic/publications/09_icde.pdf|Perm: Processing provenance and data on the same data model through query rewriting]] (ICDE 2009) – Boris Glavic, Gustavo Alonso
  * [[http://portal.acm.org/citation.cfm?id=1516472|Provenance for nested subqueries]] (EDBT 2009) - Boris Glavic, Gustavo Alonso
  * [[http://portal.acm.org/citation.cfm?id=1559980|The Perm Provenance Management System in Action]] (SIGMOD 2009, Demo) - Boris Glavic, Gustavo Alonso

== Data Model ==
The provenance of query is represented as a single relation that contains the original query results augmented with provenance information.

== Query Language ==
Perm uses an SQL language extension called SQL-PLE to enable a user to issue provenance queries (e.g. SELECT PROVENANCE).

== System ==
Perm rewrites provenance queries to normal SQL queries inside PostgresSQL (between parser and planner).

== Example ==
shop
^name^ numEmpl^
|Merdies| 3|
|Joba| 14|

sales
^sName^ itemId^
|Merdies | 1|
|Merdies | 2|
|Merdies | 2|
|Joba| 3|
|Joba| 3|

items
^id^price^
|1|100|
|2|10|
|3|25|

SELECT name, sum(price)
FROM shop, sales, items
WHERE name=sName AND itemID=id
GROUP BY name
^name^sum(price)^
|Merdies|120|
|Joba|50|

SELECT PROVENANCE name, sum(price)
FROM shop, sales, items
WHERE name=sName AND itemID=id
GROUP BY name
^name ^sum(price) ^pName ^pNumEmpl ^pSName ^pItemId ^pId ^pPrice^
|Merdies |120 |Merdies |3 |Merdies |1 |1 |100|
|Merdies |120 |Merdies |3 |Merdies |2 |2 |10|
|Merdies |120 |Merdies |3 |Merdies |2 |2 |10|
|Joba |50 |Joba |14 |Joba |3 |3 |25|
|Joba |50 |Joba |14 |Joba |3 |3 |25|