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authorMike Bayer <mike_mp@zzzcomputing.com>2011-02-09 16:30:49 -0500
committerMike Bayer <mike_mp@zzzcomputing.com>2011-02-09 16:30:49 -0500
commite80eac22a8669ada5ffaabbcfa8a991eee140697 (patch)
treee131a8af5a48bd3676c1ad64bdf496eba94ac52b /lib/sqlalchemy/sql
parent3f30fb065c3b6baa8d7870bb0682d20ad37a62a2 (diff)
downloadsqlalchemy-e80eac22a8669ada5ffaabbcfa8a991eee140697.tar.gz
- figured out the ::autodata directive, can move the docstring for
expression.func into the .py module - added a note about logging only being checked on new connections, as one user had this issue awhile back, and I suspect it for a current ML user issue
Diffstat (limited to 'lib/sqlalchemy/sql')
-rw-r--r--lib/sqlalchemy/sql/expression.py35
1 files changed, 35 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 3bc056fae..04ca147bb 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -1025,6 +1025,41 @@ class _FunctionGenerator(object):
# "func" global - i.e. func.count()
func = _FunctionGenerator()
+"""Generate SQL function expressions.
+
+ ``func`` is a special object instance which generates SQL functions based on name-based attributes, e.g.::
+
+ >>> print func.count(1)
+ count(:param_1)
+
+ Any name can be given to `func`. If the function name is unknown to
+ SQLAlchemy, it will be rendered exactly as is. For common SQL functions
+ which SQLAlchemy is aware of, the name may be interpreted as a *generic
+ function* which will be compiled appropriately to the target database::
+
+ >>> print func.current_timestamp()
+ CURRENT_TIMESTAMP
+
+ To call functions which are present in dot-separated packages, specify them in the same manner::
+
+ >>> print func.stats.yield_curve(5, 10)
+ stats.yield_curve(:yield_curve_1, :yield_curve_2)
+
+ SQLAlchemy can be made aware of the return type of functions to enable
+ type-specific lexical and result-based behavior. For example, to ensure
+ that a string-based function returns a Unicode value and is similarly
+ treated as a string in expressions, specify
+ :class:`~sqlalchemy.types.Unicode` as the type:
+
+ >>> print func.my_string(u'hi', type_=Unicode) + ' ' + \
+ ... func.my_string(u'there', type_=Unicode)
+ my_string(:my_string_1) || :my_string_2 || my_string(:my_string_3)
+
+ Functions which are interpreted as "generic" functions know how to
+ calculate their return type automatically. For a listing of known generic
+ functions, see :ref:`generic_functions`.
+
+"""
# "modifier" global - i.e. modifier.distinct
# TODO: use UnaryExpression for this instead ?