<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Utility Functions</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.6.17 Documentation" HREF="index.html"><LINK REL="UP" TITLE="PL/Python - Python Procedural Language" HREF="plpython.html"><LINK REL="PREVIOUS" TITLE="Explicit Subtransactions" HREF="plpython-subtransaction.html"><LINK REL="NEXT" TITLE="Environment Variables" HREF="plpython-envar.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2020-02-15T12:30:38"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="4" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.6.17 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="Explicit Subtransactions" HREF="plpython-subtransaction.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="plpython.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 44. PL/Python - Python Procedural Language</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Environment Variables" HREF="plpython-envar.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="PLPYTHON-UTIL" >44.9. Utility Functions</A ></H1 ><P > The <TT CLASS="LITERAL" >plpy</TT > module also provides the functions <P ></P ><TABLE BORDER="0" ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >plpy.debug(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.log(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.info(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.notice(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.warning(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.error(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >plpy.fatal(<TT CLASS="REPLACEABLE" ><I >msg, **kwargs</I ></TT >)</TT ></TD ></TR ></TBODY ></TABLE ><P ></P > <CODE CLASS="FUNCTION" >plpy.error</CODE > and <CODE CLASS="FUNCTION" >plpy.fatal</CODE > actually raise a Python exception which, if uncaught, propagates out to the calling query, causing the current transaction or subtransaction to be aborted. <TT CLASS="LITERAL" >raise plpy.Error(<TT CLASS="REPLACEABLE" ><I >msg</I ></TT >)</TT > and <TT CLASS="LITERAL" >raise plpy.Fatal(<TT CLASS="REPLACEABLE" ><I >msg</I ></TT >)</TT > are equivalent to calling <TT CLASS="LITERAL" >plpy.error(<TT CLASS="REPLACEABLE" ><I >msg</I ></TT >)</TT > and <TT CLASS="LITERAL" >plpy.fatal(<TT CLASS="REPLACEABLE" ><I >msg</I ></TT >)</TT >, respectively but the <TT CLASS="LITERAL" >raise</TT > form does not allow passing keyword arguments. The other functions only generate messages of different priority levels. Whether messages of a particular priority are reported to the client, written to the server log, or both is controlled by the <A HREF="runtime-config-logging.html#GUC-LOG-MIN-MESSAGES" >log_min_messages</A > and <A HREF="runtime-config-client.html#GUC-CLIENT-MIN-MESSAGES" >client_min_messages</A > configuration variables. See <A HREF="runtime-config.html" >Chapter 19</A > for more information. </P ><P > The <TT CLASS="REPLACEABLE" ><I >msg</I ></TT > argument is given as a positional argument. For backward compatibility, more than one positional argument can be given. In that case, the string representation of the tuple of positional arguments becomes the message reported to the client. </P ><P > The following keyword-only arguments are accepted: <P ></P ><TABLE BORDER="0" ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >detail</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >hint</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >sqlstate</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >schema_name</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >table_name</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >column_name</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >datatype_name</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >constraint_name</TT ></TD ></TR ></TBODY ></TABLE ><P ></P > The string representation of the objects passed as keyword-only arguments is used to enrich the messages reported to the client. For example: </P><PRE CLASS="PROGRAMLISTING" >CREATE FUNCTION raise_custom_exception() RETURNS void AS $$ plpy.error("custom exception message", detail="some info about exception", hint="hint for users") $$ LANGUAGE plpythonu; =# SELECT raise_custom_exception(); ERROR: plpy.Error: custom exception message DETAIL: some info about exception HINT: hint for users CONTEXT: Traceback (most recent call last): PL/Python function "raise_custom_exception", line 4, in <module> hint="hint for users") PL/Python function "raise_custom_exception"</PRE ><P> </P ><P > Another set of utility functions are <TT CLASS="LITERAL" >plpy.quote_literal(<TT CLASS="REPLACEABLE" ><I >string</I ></TT >)</TT >, <TT CLASS="LITERAL" >plpy.quote_nullable(<TT CLASS="REPLACEABLE" ><I >string</I ></TT >)</TT >, and <TT CLASS="LITERAL" >plpy.quote_ident(<TT CLASS="REPLACEABLE" ><I >string</I ></TT >)</TT >. They are equivalent to the built-in quoting functions described in <A HREF="functions-string.html" >Section 9.4</A >. They are useful when constructing ad-hoc queries. A PL/Python equivalent of dynamic SQL from <A HREF="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" >Example 41-1</A > would be: </P><PRE CLASS="PROGRAMLISTING" >plpy.execute("UPDATE tbl SET %s = %s WHERE key = %s" % ( plpy.quote_ident(colname), plpy.quote_nullable(newvalue), plpy.quote_literal(keyvalue)))</PRE ><P> </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="plpython-subtransaction.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="plpython-envar.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Explicit Subtransactions</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="plpython.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Environment Variables</TD ></TR ></TABLE ></DIV ></BODY ></HTML >