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Diffstat (limited to 'doc/src/sgml/plpython.sgml')
| -rw-r--r-- | doc/src/sgml/plpython.sgml | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/doc/src/sgml/plpython.sgml b/doc/src/sgml/plpython.sgml index befd6afb15e..e05c2937b1f 100644 --- a/doc/src/sgml/plpython.sgml +++ b/doc/src/sgml/plpython.sgml @@ -858,6 +858,9 @@ $$ LANGUAGE plpythonu; <literal>plpy.<replaceable>foo</replaceable></literal>. </para> + <sect2> + <title>Database Access Functions</title> + <para> The <literal>plpy</literal> module provides two functions called <function>execute</function> and @@ -937,6 +940,33 @@ CREATE FUNCTION usesavedplan() RETURNS trigger AS $$ $$ LANGUAGE plpythonu; </programlisting> </para> + + </sect2> + + <sect2> + <title>Trapping Errors</title> + + <para> + Functions accessing the database might encounter errors, which + will cause them to abort and raise an exception. Both + <function>plpy.execute</function> and + <function>plpy.prepare</function> can raise an instance of + <literal>plpy.SPIError</literal>, which by default will terminate + the function. This error can be handled just like any other + Python exception, by using the <literal>try/except</literal> + construct. For example: +<programlisting> +CREATE FUNCTION try_adding_joe() RETURNS text AS $$ + try: + plpy.execute("INSERT INTO users(username) VALUES ('joe')") + except plpy.SPIError: + return "something went wrong" + else: + return "Joe added" +$$ LANGUAGE plpythonu; +</programlisting> + </para> + </sect2> </sect1> <sect1 id="plpython-util"> |