diff options
Diffstat (limited to 'lib/sqlalchemy/sql/expression.py')
| -rw-r--r-- | lib/sqlalchemy/sql/expression.py | 66 |
1 files changed, 48 insertions, 18 deletions
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 0f93643dc..ede3235c5 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -791,31 +791,51 @@ def table(name, *columns): """ return TableClause(name, *columns) -def bindparam(key, value=None, type_=None, unique=False, required=False): +def bindparam(key, value=None, type_=None, unique=False, required=False, callable_=None): """Create a bind parameter clause with the given key. - value - a default value for this bind parameter. a bindparam with a - value is called a ``value-based bindparam``. - - type\_ - a sqlalchemy.types.TypeEngine object indicating the type of this - bind param, will invoke type-specific bind parameter processing + :param key: + the key for this bind param. Will be used in the generated + SQL statement for dialects that use named parameters. This + value may be modified when part of a compilation operation, + if other :class:`_BindParamClause` objects exist with the same + key, or if its length is too long and truncation is + required. - unique - if True, bind params sharing the same name will have their - underlying ``key`` modified to a uniquely generated name. - mostly useful with value-based bind params. + :param value: + Initial value for this bind param. This value may be + overridden by the dictionary of parameters sent to statement + compilation/execution. + + :param callable\_: + A callable function that takes the place of "value". The function + will be called at statement execution time to determine the + ultimate value. Used for scenarios where the actual bind + value cannot be determined at the point at which the clause + construct is created, but embeded bind values are still desirable. + + :param type\_: + A ``TypeEngine`` object that will be used to pre-process the + value corresponding to this :class:`_BindParamClause` at + execution time. - required - A value is required at execution time. - + :param unique: + if True, the key name of this BindParamClause will be + modified if another :class:`_BindParamClause` of the same name + already has been located within the containing + :class:`ClauseElement`. + + :param required: + a value is required at execution time. + """ if isinstance(key, ColumnClause): return _BindParamClause(key.name, value, type_=key.type, + callable_=callable_, unique=unique, required=required) else: return _BindParamClause(key, value, type_=type_, + callable_=callable_, unique=unique, required=required) def outparam(key, type_=None): @@ -2315,6 +2335,7 @@ class _BindParamClause(ColumnElement): quote = None def __init__(self, key, value, type_=None, unique=False, + callable_=None, isoutparam=False, required=False, _compared_to_operator=None, _compared_to_type=None): @@ -2332,7 +2353,14 @@ class _BindParamClause(ColumnElement): Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution. - + + :param callable\_: + A callable function that takes the place of "value". The function + will be called at statement execution time to determine the + ultimate value. Used for scenarios where the actual bind + value cannot be determined at the point at which the clause + construct is created, but embeded bind values are still desirable. + :param type\_: A ``TypeEngine`` object that will be used to pre-process the value corresponding to this :class:`_BindParamClause` at @@ -2361,6 +2389,7 @@ class _BindParamClause(ColumnElement): self._orig_key = key or 'param' self.unique = unique self.value = value + self.callable = callable_ self.isoutparam = isoutparam self.required = required if type_ is None: @@ -2405,8 +2434,9 @@ class _BindParamClause(ColumnElement): d = self.__dict__.copy() v = self.value - if util.callable(v): - v = v() + if self.callable: + v = self.callable() + d['callable'] = None d['value'] = v return d |