sortas="PL/Python">PL/Python is passed to a
function, return the value None. This can be done whether the
function is strict or not.
+
+
+
Arrays, Lists
SQL array values are passed into PL/Python as a Python list. To
return an SQL array value out of a PL/Python function, return a
(1 row)
+
+
+
Composite Types
Composite-type arguments are passed to the function as Python mappings. The
element names of the mapping are the attribute names of the composite type.
+
- If you do not provide a return value, Python returns the default
-
None.
PL/Python translates
- Python's None into the SQL null value.
-
-
+
+
Set-Returning Functions
A
PL/Python function can also return sets of
scalar or composite types. There are several ways to achieve this because
- Currently, due to Python
+ Due to Python
some debug versions of Python 2.4
(configured and compiled with option --with-pydebug)
+
+
+
+
Sharing Data
The global dictionary SD is available to store
data between function calls. This variable is private static data.
When a function is used as a trigger, the dictionary
- TD contains trigger-related values.
- TD["event"] contains
- the event as a string (INSERT, UPDATE,
- DELETE, TRUNCATE, or UNKNOWN).
- TD["when"] contains one of BEFORE,
- AFTER, or UNKNOWN.
- TD["level"] contains one of ROW,
- STATEMENT, or UNKNOWN.
- For a row-level trigger, the trigger
- rows are in TD["new"] and/or TD["old"]
- depending on the trigger event.
- TD["name"] contains the trigger name,
- TD["table_name"] contains the name of the table on which the trigger occurred,
- TD["table_schema"] contains the schema of the table on which the trigger occurred,
- and TD["relid"] contains the OID of the table on
- which the trigger occurred. If the CREATE TRIGGER command
- included arguments, they are available in TD["args"][0] to
- TD["args"][n-1].
+ TD contains trigger-related values:
+
+
+ TD["event"]
+
+ contains the event as a string:
+ INSERT, UPDATE,
+ DELETE, TRUNCATE,
+ or UNKNOWN.
+
+
+
+
+
+ TD["when"]
+
+ contains one of BEFORE, AFTER,
+ or UNKNOWN.
+
+
+
+
+
+ TD["level"]
+
+ contains one of ROW,
+ STATEMENT, or UNKNOWN.
+
+
+
+
+
+ TD["new"]
+ TD["old"]
+
+ For a row-level trigger, one or both of these fields contain
+ the respective trigger rows, depending on the trigger event.
+
+
+
+
+
+ TD["name"]
+
+ contains the trigger name.
+
+
+
+
+
+ TD["table_name"]
+
+ contains the name of the table on which the trigger occurred.
+
+
+
+
+
+ TD["table_schema"]
+
+ contains the schema of the table on which the trigger occurred.
+
+
+
+
+
+ TD["relid"]
+
+ contains the OID of the table on which the trigger occurred.
+
+
+
+
+
+ TD["args"]
+
+ If the CREATE TRIGGER command
+ included arguments, they are available in TD["args"][0] to
+ TD["args"][n-1].
+
+
+
+
The PL/Python language module automatically imports a Python module
called plpy. The functions and constants in
this module are available to you in the Python code as
- plpy.foo. At present
- plpy implements the functions
- plpy.debug(msg),
- plpy.log(msg),
- plpy.info(msg),
- plpy.notice(msg),
- plpy.warning(msg),
- plpy.error(msg), and
-
plpy.fatal(msg).
elogin PL/Python- 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 and
- plpy.fatal, respectively.
- 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
- and
- configuration
- variables. See for more information.
+ plpy.foo.
- Additionally, the plpy module provides two
+ The plpy module provides two
functions called execute and
prepare. Calling
plpy.execute with a query string and an
In order to make effective use of this across function calls
one needs to use one of the persistent storage dictionaries
SD or GD (see
- funcs">). For example:
+ sharing">). For example:
CREATE FUNCTION usesavedplan() RETURNS trigger AS $$
if SD.has_key("plan"):
-
-
-
-
-
Restricted Environment
-
+
+
Utility Functions
- The current version of
PL/Python- functions as a trusted language only; access to the file system and
- other local resources is disabled. Specifically,
-
PL/Python uses the Python restricted
- execution environment, further restricts it to prevent the use of
- the file open call, and allows only modules from a
- specific list to be imported. Presently, that list includes:
- array, bisect, binascii,
- calendar, cmath, codecs,
- errno, marshal, math, md5,
- mpz, operator, pcre,
- pickle, random, re, regex,
- sre, sha, string, StringIO,
- struct, time, whrandom, and
- zlib.
+ The plpy module also provides the functions
+ plpy.debug(msg),
+ plpy.log(msg),
+ plpy.info(msg),
+ plpy.notice(msg),
+ plpy.warning(msg),
+ plpy.error(msg), and
+
plpy.fatal(msg).
elogin PL/Python+ 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 and
+ plpy.fatal, respectively.
+ 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
+ and
+ configuration
+ variables. See for more information.
-]]>
-
projects / postgresql.git / commitdiff