1
0
mirror of https://github.com/postgres/postgres.git synced 2025-06-23 14:01:44 +03:00

Hook up the plpython result-object nrows and status methods correctly.

Adjust documentation to match current reality.
This commit is contained in:
Tom Lane
2004-12-17 02:14:48 +00:00
parent ff5a354ece
commit dfdae5d63c
2 changed files with 29 additions and 56 deletions

View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpython.sgml,v 1.24 2004/09/13 20:05:18 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpython.sgml,v 1.25 2004/12/17 02:14:44 tgl Exp $ -->
<chapter id="plpython">
<title>PL/Python - Python Procedural Language</title>
@ -46,7 +46,8 @@
<title>PL/Python Functions</title>
<para>
The Python code you write gets transformed into a Python function. E.g.,
The Python code you write gets transformed into a Python function.
For example,
<programlisting>
CREATE FUNCTION myfunc(text) RETURNS text
AS 'return args[0]'
@ -60,13 +61,14 @@ def __plpython_procedure_myfunc_23456():
return args[0]
</programlisting>
assuming that 23456 is the OID of the function.
assuming that 23456 is the OID assigned to the function by
<productname>PostgreSQL</productname>.
</para>
<para>
If you do not provide a return value, Python returns the default
<symbol>None</symbol>. The language module translates Python's
<symbol>None</symbol> into the SQL null
<symbol>None</symbol>. <application>PL/Python</application> translates
Python's <symbol>None</symbol> into the SQL null
value.<indexterm><primary>null value</><secondary
sortas="PL/Python">in PL/Python</></indexterm>
</para>
@ -108,7 +110,7 @@ def __plpython_procedure_myfunc_23456():
</indexterm>
<para>
When a function is used in a trigger, the dictionary
When a function is used as a trigger, the dictionary
<literal>TD</literal> contains trigger-related values. The trigger
rows are in <literal>TD["new"]</> and/or <literal>TD["old"]</>
depending on the trigger event. <literal>TD["event"]</> contains
@ -120,9 +122,9 @@ def __plpython_procedure_myfunc_23456():
<literal>STATEMENT</>, and <literal>UNKNOWN</>.
<literal>TD["name"]</> contains the trigger name, and
<literal>TD["relid"]</> contains the OID of the table on
which the trigger occurred. If the trigger was called with
arguments they are available in <literal>TD["args"][0]</> to
<literal>TD["args"][(n-1)]</>.
which the trigger occurred. If the <command>CREATE TRIGGER</> command
included arguments, they are available in <literal>TD["args"][0]</> to
<literal>TD["args"][(<replaceable>n</>-1)]</>.
</para>
<para>
@ -143,23 +145,23 @@ def __plpython_procedure_myfunc_23456():
this module are available to you in the Python code as
<literal>plpy.<replaceable>foo</replaceable></literal>. At present
<literal>plpy</literal> implements the functions
<literal>plpy.debug("msg")</literal>,
<literal>plpy.log("msg")</literal>,
<literal>plpy.info("msg")</literal>,
<literal>plpy.notice("msg")</literal>,
<literal>plpy.warning("msg")</literal>,
<literal>plpy.error("msg")</literal>, and
<literal>plpy.fatal("msg")</literal>. They are mostly equivalent
to calling <literal>elog(<replaceable>LEVEL</>, "msg")</literal>
<literal>plpy.debug(<replaceable>msg</>)</literal>,
<literal>plpy.log(<replaceable>msg</>)</literal>,
<literal>plpy.info(<replaceable>msg</>)</literal>,
<literal>plpy.notice(<replaceable>msg</>)</literal>,
<literal>plpy.warning(<replaceable>msg</>)</literal>,
<literal>plpy.error(<replaceable>msg</>)</literal>, and
<literal>plpy.fatal(<replaceable>msg</>)</literal>.
These are mostly equivalent to calling
<literal>elog(<replaceable>level</>, <replaceable>msg</>)</literal>
from C code.<indexterm><primary>elog</><secondary>in
PL/Python</></indexterm> <function>plpy.error</function> and
<function>plpy.fatal</function> actually raise a Python exception
which, if uncaught, causes the PL/Python module to call
<literal>elog(ERROR, msg)</literal> when the function handler
returns from the Python interpreter. Long-jumping out of the
Python interpreter is probably not good. <literal>raise
plpy.ERROR("msg")</literal> and <literal>raise
plpy.FATAL("msg")</literal> are equivalent to calling
returns from the Python interpreter. <literal>raise
plpy.ERROR(<replaceable>msg</>)</literal> and <literal>raise
plpy.FATAL(<replaceable>msg</>)</literal> are equivalent to calling
<function>plpy.error</function> and
<function>plpy.fatal</function>, respectively.
</para>
@ -210,17 +212,6 @@ rv = plpy.execute(plan, [ "name" ], 5)
The third argument is the limit and is optional.
</para>
<para>
In the current version, any database error encountered while
running a <application>PL/Python</application> function will result
in the immediate termination of that function by the server; it is
not possible to trap error conditions using Python <literal>try
... catch</literal> constructs. For example, a syntax error in an
SQL statement passed to the <literal>plpy.execute</literal> call
will terminate the function. This behavior may be changed in a
future release.
</para>
<para>
When you prepare a plan using the PL/Python module it is
automatically saved. Read the SPI documentation (<xref