46.9. Utility Functions

46.9. Utility Functions
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+ The plpy module also provides the functions +

plpy.debug(msg, **kwargs)

plpy.log(msg, **kwargs)

plpy.info(msg, **kwargs)

plpy.notice(msg, **kwargs)

plpy.warning(msg, **kwargs)

plpy.error(msg, **kwargs)

plpy.fatal(msg, **kwargs)

+ + plpy.error and plpy.fatal + actually raise a Python exception which, if uncaught, propagates out to + the calling query, causing the current transaction or subtransaction to + be aborted. raise plpy.Error(msg) and + raise plpy.Fatal(msg) are + equivalent to calling plpy.error(msg) and + plpy.fatal(msg), respectively but + the raise 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 + log_min_messages and + client_min_messages configuration + variables. See Chapter 20 for more information. +

+ The msg 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. +

+ The following keyword-only arguments are accepted: +

detail

hint

sqlstate

schema_name

table_name

column_name

datatype_name

constraint_name

+ The string representation of the objects passed as keyword-only arguments + is used to enrich the messages reported to the client. For example: + +

+CREATE FUNCTION raise_custom_exception() RETURNS void AS $$
+plpy.error("custom exception message",
+           detail="some info about exception",
+           hint="hint for users")
+$$ LANGUAGE plpython3u;
+
+=# 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"
+

+ Another set of utility functions are + plpy.quote_literal(string), + plpy.quote_nullable(string), and + plpy.quote_ident(string). They + are equivalent to the built-in quoting functions described in Section 9.4. They are useful when constructing + ad-hoc queries. A PL/Python equivalent of dynamic SQL from Example 43.1 would be: +

+plpy.execute("UPDATE tbl SET %s = %s WHERE key = %s" % (
+    plpy.quote_ident(colname),
+    plpy.quote_nullable(newvalue),
+    plpy.quote_literal(keyvalue)))
+

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