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SQL/PSM (SQL/Persistent Stored Modules) is an ISO standard mainly defining an extension of SQL with a procedural language for use in stored procedures. Initially published in 1996 as an extension of SQL-92 (ISO/IEC 9075-4:1996, a version sometimes called PSM-96 or even SQL-92/PSM[2]), SQL/PSM was later incorporated into the multi-part SQL:1999 standard, and has been part 4 of that standard since then, most recently in SQL:2016. The SQL:1999 part 4 covered less than the original PSM-96 because the SQL statements for defining, managing, and invoking routines were actually incorporated into part 2 SQL/Foundation, leaving only the procedural language itself as SQL/PSM.[3] The SQL/PSM facilities are still optional as far as the SQL standard is concerned; most of them are grouped in Features P001-P008.

SQL/PSM
ParadigmMulti-paradigm
First appeared1996
Stable release
OSCross-platform (multi-platform)
Major implementations
PL/SQL
MySQL/MariaDB
IBM's SQL PL
Mimer SQL
Influenced by
PL/SQL
Ada[1]

SQL/PSM standardizes syntax and semantics for control flow, exception handling (called "condition handling" in SQL/PSM), local variables, assignment of expressions to variables and parameters, and (procedural) use of cursors. It also defines an information schema (metadata) for stored procedures. SQL/PSM is one language in which methods for the SQL:1999 structured types can be defined. The other is Java, via SQL/JRT.

SQL/PSM is derived, seemingly directly, from Oracle's PL/SQL. Oracle developed PL/SQL and released it in 1991, basing the language on the US Department of Defense's Ada programming language. However, Oracle has maintained a distance from the standard in its documentation. IBM's SQL PL (used in DB2) and Mimer SQL's PSM[4] were the first two products officially implementing SQL/PSM. It is commonly thought that these two languages, and perhaps also MySQL/MariaDB's procedural language, are closest to the SQL/PSM standard. [5][6] However, a PostgreSQL addon implements SQL/PSM[7][8][9][10] (alongside its other procedural languages like the PL/SQL-derived plpgsql), although it is not part of the core product.[11]

RDF functionality in OpenLink Virtuoso was developed entirely through SQL/PSM, combined with custom datatypes (e.g., ANY for handling URI and Literal relation objects), sophisticated indexing, and flexible physical storage choices (column-wise or row-wise).

See alsoEdit

The following implementations adopt the standard, but they are not 100% compatible to SQL/PSM:

Open source:

Proprietary:

ReferencesEdit

  1. ^ Gulutzan, Peter (2015), Stored Procedures: critiques and defences
  2. ^ Eisenberg, A. (1996). "New standard for stored procedures in SQL". ACM SIGMOD Record. 25 (4): 81–88. doi:10.1145/245882.245907.
  3. ^ Melton, Jim; Simon, Alan R (2002). SQL: 1999. Morgan Kaufmann. pp. 541–42. ISBN 978-1-55860-456-8.
  4. ^ https://developer.mimer.com/documentation/sql/stored-procedures-in-mimer-sql/
  5. ^ a b Harrison, Guy; Feuerstein, Steven (2008). MySQL Stored Procedure Programming. O'Reilly. p. 49. ISBN 978-0-596-10089-6.
  6. ^ a b https://mariadb.com/kb/en/library/stored-procedures/
  7. ^ plpsm0 (git) (repository).
  8. ^ Announce, PostgreSQL, May 2011.
  9. ^ 2012-2's Proposal PL/pgPSM announce
  10. ^ SQL/PSM (wiki) (manual), PostgreSQL, 2008.
  11. ^ "SQL Conformance", Documentation (9.2 ed.), PostgreSQL.
  12. ^ http://hsqldb.org/doc/2.0/guide/sqlroutines-chapt.html#src_psm_routines
  13. ^ http://docs.openlinksw.com/virtuoso/ch-sqlprocedures/
  14. ^ Invantive Procedural SQL grammar

Further readingEdit

  • Jim Melton, Understanding SQL's Stored Procedures: A Complete Guide to SQL/PSM, Morgan Kaufmann Publishers, 1998, ISBN 1-55860-461-8