I just got my hands on the real SQL99 stuff, dated September 1999, and it
contains a function creation syntax that is strikingly similar to ours,
which would make it a shame not to at least try to play along. Below is a
heavily reduced BNF which should give you some idea -- note in particular
the NULL call conventions. Download your copy at
<ftp://jerry.ece.umassd.edu/isowg3/x3h2/Standards/>.
<schema function> ::= CREATE FUNCTION <schema qualified name> <SQL parameter
declarationlist> RETURNS <data type> [ <routine characteristics>... ] [
<dispatchclause> ] <routine body>
<dispatch clause> ::= STATIC DISPATCH /* no idea */
<SQL parameter declaration list> ::= <left paren> [ <SQL parameter declaration> [ {
<comma><SQL parameter declaration> }... ] ] <right paren>
<SQL parameter declaration> ::= [ <parameter mode> ] [ <SQL parameter name> ]
<parametertype> [ RESULT ]
<parameter mode> ::= IN | OUT | INOUT /* default is IN */
<routine body> ::= <SQL routine body> | <external body reference> <SQL routine
body>::= <SQL procedure statement> /* which means a particular subset of SQL statements */ <external body
reference>::= EXTERNAL [ NAME <external routine name> ] [ <parameter style clause> ]
[ <external security clause> ]
<routine characteristic> ::= LANGUAGE { ADA | C | COBOL | FORTRAN | MUMPS | PASCAL | PLI | SQL }
| PARAMETER STYLE { SQL | GENERAL } | SPECIFIC <specific name> /* apparently to disambiguate
overloadedfunctions */ | { DETERMINISTIC | NOT DETERMINISTIC } | { NO SQL | CONTAINS SQL |
READSSQL DATA | MODIFIES SQL DATA } | { RETURNS NULL ON NULL INPUT | CALLED ON NULL INPUT }
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | <transform group specification> | <dynamic
resultsets characteristic>
--
Peter Eisentraut Sernanders väg 10:115
peter_e@gmx.net 75262 Uppsala
http://yi.org/peter-e/ Sweden
