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- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>45.10. Utility Functions</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="plpython-transactions.html" title="45.9. Transaction Management" /><link rel="next" href="plpython-envar.html" title="45.11. Environment Variables" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">45.10. Utility Functions</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="plpython-transactions.html" title="45.9. Transaction Management">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="plpython.html" title="Chapter 45. PL/Python - Python Procedural Language">Up</a></td><th width="60%" align="center">Chapter 45. PL/Python - Python Procedural Language</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="plpython-envar.html" title="45.11. Environment Variables">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="PLPYTHON-UTIL"><div class="titlepage"><div><div><h2 class="title" style="clear: both">45.10. Utility Functions</h2></div></div></div><p>
- The <code class="literal">plpy</code> module also provides the functions
- </p><table border="0" summary="Simple list" class="simplelist"><tr><td><code class="literal">plpy.debug(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.log(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.info(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.notice(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.warning(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.error(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr><tr><td><code class="literal">plpy.fatal(<em class="replaceable"><code>msg, **kwargs</code></em>)</code></td></tr></table><p>
- <a id="id-1.8.11.18.2.3" class="indexterm"></a>
- <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. <code class="literal">raise plpy.Error(<em class="replaceable"><code>msg</code></em>)</code> and
- <code class="literal">raise plpy.Fatal(<em class="replaceable"><code>msg</code></em>)</code> are
- equivalent to calling <code class="literal">plpy.error(<em class="replaceable"><code>msg</code></em>)</code> and
- <code class="literal">plpy.fatal(<em class="replaceable"><code>msg</code></em>)</code>, respectively but
- the <code class="literal">raise</code> 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 class="xref" href="runtime-config-logging.html#GUC-LOG-MIN-MESSAGES">log_min_messages</a> and
- <a class="xref" href="runtime-config-client.html#GUC-CLIENT-MIN-MESSAGES">client_min_messages</a> configuration
- variables. See <a class="xref" href="runtime-config.html" title="Chapter 19. Server Configuration">Chapter 19</a> for more information.
- </p><p>
- The <em class="replaceable"><code>msg</code></em> 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><table border="0" summary="Simple list" class="simplelist"><tr><td><code class="literal">detail</code></td></tr><tr><td><code class="literal">hint</code></td></tr><tr><td><code class="literal">sqlstate</code></td></tr><tr><td><code class="literal">schema_name</code></td></tr><tr><td><code class="literal">table_name</code></td></tr><tr><td><code class="literal">column_name</code></td></tr><tr><td><code class="literal">datatype_name</code></td></tr><tr><td><code class="literal">constraint_name</code></td></tr></table><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
- <code class="literal">plpy.quote_literal(<em class="replaceable"><code>string</code></em>)</code>,
- <code class="literal">plpy.quote_nullable(<em class="replaceable"><code>string</code></em>)</code>, and
- <code class="literal">plpy.quote_ident(<em class="replaceable"><code>string</code></em>)</code>. They
- are equivalent to the built-in quoting functions described in <a class="xref" href="functions-string.html" title="9.4. String Functions and Operators">Section 9.4</a>. They are useful when constructing
- ad-hoc queries. A PL/Python equivalent of dynamic SQL from <a class="xref" href="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" title="Example 42.1. Quoting Values in Dynamic Queries">Example 42.1</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 /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="plpython-transactions.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="plpython.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="plpython-envar.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">45.9. Transaction Management </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 45.11. Environment Variables</td></tr></table></div></body></html>
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