918 lines
31 KiB
Python
918 lines
31 KiB
Python
import copy
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import datetime
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from django.conf import settings
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from django.core.exceptions import FieldError
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from django.db.backends import utils as backend_utils
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from django.db.models import fields
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from django.db.models.constants import LOOKUP_SEP
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from django.db.models.query_utils import Q, refs_aggregate
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from django.utils import six, timezone
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from django.utils.functional import cached_property
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class Combinable(object):
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"""
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Provides the ability to combine one or two objects with
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some connector. For example F('foo') + F('bar').
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"""
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# Arithmetic connectors
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ADD = '+'
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SUB = '-'
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MUL = '*'
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DIV = '/'
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POW = '^'
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# The following is a quoted % operator - it is quoted because it can be
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# used in strings that also have parameter substitution.
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MOD = '%%'
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# Bitwise operators - note that these are generated by .bitand()
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# and .bitor(), the '&' and '|' are reserved for boolean operator
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# usage.
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BITAND = '&'
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BITOR = '|'
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def _combine(self, other, connector, reversed, node=None):
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if not hasattr(other, 'resolve_expression'):
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# everything must be resolvable to an expression
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if isinstance(other, datetime.timedelta):
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other = DurationValue(other, output_field=fields.DurationField())
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else:
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other = Value(other)
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if reversed:
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return CombinedExpression(other, connector, self)
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return CombinedExpression(self, connector, other)
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#############
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# OPERATORS #
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#############
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def __add__(self, other):
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return self._combine(other, self.ADD, False)
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def __sub__(self, other):
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return self._combine(other, self.SUB, False)
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def __mul__(self, other):
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return self._combine(other, self.MUL, False)
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def __truediv__(self, other):
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return self._combine(other, self.DIV, False)
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def __div__(self, other): # Python 2 compatibility
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return type(self).__truediv__(self, other)
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def __mod__(self, other):
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return self._combine(other, self.MOD, False)
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def __pow__(self, other):
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return self._combine(other, self.POW, False)
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def __and__(self, other):
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raise NotImplementedError(
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"Use .bitand() and .bitor() for bitwise logical operations."
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)
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def bitand(self, other):
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return self._combine(other, self.BITAND, False)
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def __or__(self, other):
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raise NotImplementedError(
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"Use .bitand() and .bitor() for bitwise logical operations."
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)
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def bitor(self, other):
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return self._combine(other, self.BITOR, False)
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def __radd__(self, other):
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return self._combine(other, self.ADD, True)
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def __rsub__(self, other):
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return self._combine(other, self.SUB, True)
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def __rmul__(self, other):
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return self._combine(other, self.MUL, True)
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def __rtruediv__(self, other):
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return self._combine(other, self.DIV, True)
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def __rdiv__(self, other): # Python 2 compatibility
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return type(self).__rtruediv__(self, other)
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def __rmod__(self, other):
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return self._combine(other, self.MOD, True)
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def __rpow__(self, other):
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return self._combine(other, self.POW, True)
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def __rand__(self, other):
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raise NotImplementedError(
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"Use .bitand() and .bitor() for bitwise logical operations."
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)
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def __ror__(self, other):
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raise NotImplementedError(
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"Use .bitand() and .bitor() for bitwise logical operations."
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)
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class BaseExpression(object):
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"""
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Base class for all query expressions.
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"""
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# aggregate specific fields
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is_summary = False
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def get_db_converters(self, connection):
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return [self.convert_value] + self.output_field.get_db_converters(connection)
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def __init__(self, output_field=None):
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self._output_field = output_field
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def get_source_expressions(self):
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return []
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def set_source_expressions(self, exprs):
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assert len(exprs) == 0
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def _parse_expressions(self, *expressions):
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return [
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arg if hasattr(arg, 'resolve_expression') else (
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F(arg) if isinstance(arg, six.string_types) else Value(arg)
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) for arg in expressions
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]
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def as_sql(self, compiler, connection):
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"""
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Responsible for returning a (sql, [params]) tuple to be included
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in the current query.
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Different backends can provide their own implementation, by
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providing an `as_{vendor}` method and patching the Expression:
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```
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def override_as_sql(self, compiler, connection):
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# custom logic
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return super(Expression, self).as_sql(compiler, connection)
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setattr(Expression, 'as_' + connection.vendor, override_as_sql)
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```
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Arguments:
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* compiler: the query compiler responsible for generating the query.
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Must have a compile method, returning a (sql, [params]) tuple.
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Calling compiler(value) will return a quoted `value`.
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* connection: the database connection used for the current query.
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Returns: (sql, params)
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Where `sql` is a string containing ordered sql parameters to be
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replaced with the elements of the list `params`.
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"""
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raise NotImplementedError("Subclasses must implement as_sql()")
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@cached_property
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def contains_aggregate(self):
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for expr in self.get_source_expressions():
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if expr and expr.contains_aggregate:
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return True
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return False
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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"""
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Provides the chance to do any preprocessing or validation before being
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added to the query.
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Arguments:
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* query: the backend query implementation
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* allow_joins: boolean allowing or denying use of joins
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in this query
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* reuse: a set of reusable joins for multijoins
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* summarize: a terminal aggregate clause
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* for_save: whether this expression about to be used in a save or update
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Returns: an Expression to be added to the query.
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"""
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c = self.copy()
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c.is_summary = summarize
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c.set_source_expressions([
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expr.resolve_expression(query, allow_joins, reuse, summarize)
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for expr in c.get_source_expressions()
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])
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return c
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def _prepare(self):
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"""
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Hook used by Field.get_prep_lookup() to do custom preparation.
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"""
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return self
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@property
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def field(self):
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return self.output_field
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@cached_property
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def output_field(self):
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"""
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Returns the output type of this expressions.
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"""
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if self._output_field_or_none is None:
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raise FieldError("Cannot resolve expression type, unknown output_field")
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return self._output_field_or_none
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@cached_property
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def _output_field_or_none(self):
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"""
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Returns the output field of this expression, or None if no output type
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can be resolved. Note that the 'output_field' property will raise
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FieldError if no type can be resolved, but this attribute allows for
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None values.
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"""
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if self._output_field is None:
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self._resolve_output_field()
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return self._output_field
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def _resolve_output_field(self):
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"""
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Attempts to infer the output type of the expression. If the output
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fields of all source fields match then we can simply infer the same
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type here.
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"""
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if self._output_field is None:
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sources = self.get_source_fields()
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num_sources = len(sources)
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if num_sources == 0:
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self._output_field = None
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else:
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self._output_field = sources[0]
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for source in sources:
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if source is not None and not isinstance(self._output_field, source.__class__):
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raise FieldError(
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"Expression contains mixed types. You must set output_field")
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def convert_value(self, value, expression, connection, context):
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"""
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Expressions provide their own converters because users have the option
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of manually specifying the output_field which may be a different type
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from the one the database returns.
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"""
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field = self.output_field
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internal_type = field.get_internal_type()
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if value is None:
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return value
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elif internal_type == 'FloatField':
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return float(value)
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elif internal_type.endswith('IntegerField'):
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return int(value)
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elif internal_type == 'DecimalField':
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return backend_utils.typecast_decimal(value)
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return value
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def get_lookup(self, lookup):
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return self.output_field.get_lookup(lookup)
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def get_transform(self, name):
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return self.output_field.get_transform(name)
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def relabeled_clone(self, change_map):
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clone = self.copy()
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clone.set_source_expressions(
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[e.relabeled_clone(change_map) for e in self.get_source_expressions()])
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return clone
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def copy(self):
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c = copy.copy(self)
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c.copied = True
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return c
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def refs_aggregate(self, existing_aggregates):
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"""
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Does this expression contain a reference to some of the
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existing aggregates? If so, returns the aggregate and also
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the lookup parts that *weren't* found. So, if
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exsiting_aggregates = {'max_id': Max('id')}
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self.name = 'max_id'
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queryset.filter(max_id__range=[10,100])
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then this method will return Max('id') and those parts of the
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name that weren't found. In this case `max_id` is found and the range
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portion is returned as ('range',).
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"""
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for node in self.get_source_expressions():
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agg, lookup = node.refs_aggregate(existing_aggregates)
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if agg:
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return agg, lookup
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return False, ()
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def get_group_by_cols(self):
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if not self.contains_aggregate:
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return [self]
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cols = []
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for source in self.get_source_expressions():
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cols.extend(source.get_group_by_cols())
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return cols
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def get_source_fields(self):
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"""
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Returns the underlying field types used by this
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aggregate.
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"""
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return [e._output_field_or_none for e in self.get_source_expressions()]
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def asc(self):
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return OrderBy(self)
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def desc(self):
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return OrderBy(self, descending=True)
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def reverse_ordering(self):
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return self
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class Expression(BaseExpression, Combinable):
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"""
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An expression that can be combined with other expressions.
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"""
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pass
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class CombinedExpression(Expression):
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def __init__(self, lhs, connector, rhs, output_field=None):
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super(CombinedExpression, self).__init__(output_field=output_field)
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self.connector = connector
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self.lhs = lhs
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self.rhs = rhs
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def __repr__(self):
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return "<{}: {}>".format(self.__class__.__name__, self)
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def __str__(self):
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return "{} {} {}".format(self.lhs, self.connector, self.rhs)
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def get_source_expressions(self):
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return [self.lhs, self.rhs]
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def set_source_expressions(self, exprs):
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self.lhs, self.rhs = exprs
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def as_sql(self, compiler, connection):
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try:
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lhs_output = self.lhs.output_field
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except FieldError:
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lhs_output = None
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try:
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rhs_output = self.rhs.output_field
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except FieldError:
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rhs_output = None
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if (not connection.features.has_native_duration_field and
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((lhs_output and lhs_output.get_internal_type() == 'DurationField')
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or (rhs_output and rhs_output.get_internal_type() == 'DurationField'))):
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return DurationExpression(self.lhs, self.connector, self.rhs).as_sql(compiler, connection)
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expressions = []
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expression_params = []
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sql, params = compiler.compile(self.lhs)
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expressions.append(sql)
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expression_params.extend(params)
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sql, params = compiler.compile(self.rhs)
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expressions.append(sql)
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expression_params.extend(params)
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# order of precedence
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expression_wrapper = '(%s)'
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sql = connection.ops.combine_expression(self.connector, expressions)
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return expression_wrapper % sql, expression_params
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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c = self.copy()
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c.is_summary = summarize
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c.lhs = c.lhs.resolve_expression(query, allow_joins, reuse, summarize, for_save)
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c.rhs = c.rhs.resolve_expression(query, allow_joins, reuse, summarize, for_save)
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return c
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class DurationExpression(CombinedExpression):
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def compile(self, side, compiler, connection):
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if not isinstance(side, DurationValue):
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try:
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output = side.output_field
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except FieldError:
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pass
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else:
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if output.get_internal_type() == 'DurationField':
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sql, params = compiler.compile(side)
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return connection.ops.format_for_duration_arithmetic(sql), params
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return compiler.compile(side)
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def as_sql(self, compiler, connection):
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connection.ops.check_expression_support(self)
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expressions = []
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expression_params = []
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sql, params = self.compile(self.lhs, compiler, connection)
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expressions.append(sql)
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expression_params.extend(params)
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sql, params = self.compile(self.rhs, compiler, connection)
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expressions.append(sql)
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expression_params.extend(params)
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# order of precedence
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expression_wrapper = '(%s)'
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sql = connection.ops.combine_duration_expression(self.connector, expressions)
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return expression_wrapper % sql, expression_params
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class F(Combinable):
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"""
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An object capable of resolving references to existing query objects.
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"""
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def __init__(self, name):
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"""
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Arguments:
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* name: the name of the field this expression references
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"""
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self.name = name
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def __repr__(self):
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return "{}({})".format(self.__class__.__name__, self.name)
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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return query.resolve_ref(self.name, allow_joins, reuse, summarize)
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def refs_aggregate(self, existing_aggregates):
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return refs_aggregate(self.name.split(LOOKUP_SEP), existing_aggregates)
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def asc(self):
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return OrderBy(self)
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def desc(self):
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return OrderBy(self, descending=True)
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|
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class Func(Expression):
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"""
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A SQL function call.
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"""
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function = None
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template = '%(function)s(%(expressions)s)'
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arg_joiner = ', '
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def __init__(self, *expressions, **extra):
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output_field = extra.pop('output_field', None)
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super(Func, self).__init__(output_field=output_field)
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self.source_expressions = self._parse_expressions(*expressions)
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self.extra = extra
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def __repr__(self):
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args = self.arg_joiner.join(str(arg) for arg in self.source_expressions)
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extra = ', '.join(str(key) + '=' + str(val) for key, val in self.extra.items())
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if extra:
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return "{}({}, {})".format(self.__class__.__name__, args, extra)
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return "{}({})".format(self.__class__.__name__, args)
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def get_source_expressions(self):
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return self.source_expressions
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def set_source_expressions(self, exprs):
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self.source_expressions = exprs
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|
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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c = self.copy()
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c.is_summary = summarize
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for pos, arg in enumerate(c.source_expressions):
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c.source_expressions[pos] = arg.resolve_expression(query, allow_joins, reuse, summarize, for_save)
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return c
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|
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def as_sql(self, compiler, connection, function=None, template=None):
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connection.ops.check_expression_support(self)
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sql_parts = []
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params = []
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for arg in self.source_expressions:
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arg_sql, arg_params = compiler.compile(arg)
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sql_parts.append(arg_sql)
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params.extend(arg_params)
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if function is None:
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self.extra['function'] = self.extra.get('function', self.function)
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else:
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self.extra['function'] = function
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self.extra['expressions'] = self.extra['field'] = self.arg_joiner.join(sql_parts)
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template = template or self.extra.get('template', self.template)
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return template % self.extra, params
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def copy(self):
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copy = super(Func, self).copy()
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copy.source_expressions = self.source_expressions[:]
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copy.extra = self.extra.copy()
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return copy
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|
|
|
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class Value(Expression):
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"""
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Represents a wrapped value as a node within an expression
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"""
|
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def __init__(self, value, output_field=None):
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"""
|
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Arguments:
|
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* value: the value this expression represents. The value will be
|
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added into the sql parameter list and properly quoted.
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|
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* output_field: an instance of the model field type that this
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expression will return, such as IntegerField() or CharField().
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"""
|
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super(Value, self).__init__(output_field=output_field)
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self.value = value
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|
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def __repr__(self):
|
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return "{}({})".format(self.__class__.__name__, self.value)
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|
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def as_sql(self, compiler, connection):
|
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connection.ops.check_expression_support(self)
|
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val = self.value
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# check _output_field to avoid triggering an exception
|
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if self._output_field is not None:
|
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if self.for_save:
|
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val = self.output_field.get_db_prep_save(val, connection=connection)
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else:
|
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val = self.output_field.get_db_prep_value(val, connection=connection)
|
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if val is None:
|
|
# cx_Oracle does not always convert None to the appropriate
|
|
# NULL type (like in case expressions using numbers), so we
|
|
# use a literal SQL NULL
|
|
return 'NULL', []
|
|
return '%s', [val]
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
c = super(Value, self).resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
c.for_save = for_save
|
|
return c
|
|
|
|
def get_group_by_cols(self):
|
|
return []
|
|
|
|
|
|
class DurationValue(Value):
|
|
def as_sql(self, compiler, connection):
|
|
connection.ops.check_expression_support(self)
|
|
if (connection.features.has_native_duration_field and
|
|
connection.features.driver_supports_timedelta_args):
|
|
return super(DurationValue, self).as_sql(compiler, connection)
|
|
return connection.ops.date_interval_sql(self.value)
|
|
|
|
|
|
class RawSQL(Expression):
|
|
def __init__(self, sql, params, output_field=None):
|
|
if output_field is None:
|
|
output_field = fields.Field()
|
|
self.sql, self.params = sql, params
|
|
super(RawSQL, self).__init__(output_field=output_field)
|
|
|
|
def __repr__(self):
|
|
return "{}({}, {})".format(self.__class__.__name__, self.sql, self.params)
|
|
|
|
def as_sql(self, compiler, connection):
|
|
return '(%s)' % self.sql, self.params
|
|
|
|
def get_group_by_cols(self):
|
|
return [self]
|
|
|
|
|
|
class Random(Expression):
|
|
def __init__(self):
|
|
super(Random, self).__init__(output_field=fields.FloatField())
|
|
|
|
def __repr__(self):
|
|
return "Random()"
|
|
|
|
def as_sql(self, compiler, connection):
|
|
return connection.ops.random_function_sql(), []
|
|
|
|
|
|
class Col(Expression):
|
|
def __init__(self, alias, target, output_field=None):
|
|
if output_field is None:
|
|
output_field = target
|
|
super(Col, self).__init__(output_field=output_field)
|
|
self.alias, self.target = alias, target
|
|
|
|
def __repr__(self):
|
|
return "{}({}, {})".format(
|
|
self.__class__.__name__, self.alias, self.target)
|
|
|
|
def as_sql(self, compiler, connection):
|
|
qn = compiler.quote_name_unless_alias
|
|
return "%s.%s" % (qn(self.alias), qn(self.target.column)), []
|
|
|
|
def relabeled_clone(self, relabels):
|
|
return self.__class__(relabels.get(self.alias, self.alias), self.target, self.output_field)
|
|
|
|
def get_group_by_cols(self):
|
|
return [self]
|
|
|
|
def get_db_converters(self, connection):
|
|
if self.target == self.output_field:
|
|
return self.output_field.get_db_converters(connection)
|
|
return (self.output_field.get_db_converters(connection) +
|
|
self.target.get_db_converters(connection))
|
|
|
|
|
|
class Ref(Expression):
|
|
"""
|
|
Reference to column alias of the query. For example, Ref('sum_cost') in
|
|
qs.annotate(sum_cost=Sum('cost')) query.
|
|
"""
|
|
def __init__(self, refs, source):
|
|
super(Ref, self).__init__()
|
|
self.refs, self.source = refs, source
|
|
|
|
def __repr__(self):
|
|
return "{}({}, {})".format(self.__class__.__name__, self.refs, self.source)
|
|
|
|
def get_source_expressions(self):
|
|
return [self.source]
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.source, = exprs
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
# The sub-expression `source` has already been resolved, as this is
|
|
# just a reference to the name of `source`.
|
|
return self
|
|
|
|
def relabeled_clone(self, relabels):
|
|
return self
|
|
|
|
def as_sql(self, compiler, connection):
|
|
return "%s" % connection.ops.quote_name(self.refs), []
|
|
|
|
def get_group_by_cols(self):
|
|
return [self]
|
|
|
|
|
|
class When(Expression):
|
|
template = 'WHEN %(condition)s THEN %(result)s'
|
|
|
|
def __init__(self, condition=None, then=None, **lookups):
|
|
if lookups and condition is None:
|
|
condition, lookups = Q(**lookups), None
|
|
if condition is None or not isinstance(condition, Q) or lookups:
|
|
raise TypeError("__init__() takes either a Q object or lookups as keyword arguments")
|
|
super(When, self).__init__(output_field=None)
|
|
self.condition = condition
|
|
self.result = self._parse_expressions(then)[0]
|
|
|
|
def __str__(self):
|
|
return "WHEN %r THEN %r" % (self.condition, self.result)
|
|
|
|
def __repr__(self):
|
|
return "<%s: %s>" % (self.__class__.__name__, self)
|
|
|
|
def get_source_expressions(self):
|
|
return [self.condition, self.result]
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.condition, self.result = exprs
|
|
|
|
def get_source_fields(self):
|
|
# We're only interested in the fields of the result expressions.
|
|
return [self.result._output_field_or_none]
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
c = self.copy()
|
|
c.is_summary = summarize
|
|
c.condition = c.condition.resolve_expression(query, allow_joins, reuse, summarize, False)
|
|
c.result = c.result.resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
return c
|
|
|
|
def as_sql(self, compiler, connection, template=None):
|
|
connection.ops.check_expression_support(self)
|
|
template_params = {}
|
|
sql_params = []
|
|
condition_sql, condition_params = compiler.compile(self.condition)
|
|
template_params['condition'] = condition_sql
|
|
sql_params.extend(condition_params)
|
|
result_sql, result_params = compiler.compile(self.result)
|
|
template_params['result'] = result_sql
|
|
sql_params.extend(result_params)
|
|
template = template or self.template
|
|
return template % template_params, sql_params
|
|
|
|
def get_group_by_cols(self):
|
|
# This is not a complete expression and cannot be used in GROUP BY.
|
|
cols = []
|
|
for source in self.get_source_expressions():
|
|
cols.extend(source.get_group_by_cols())
|
|
return cols
|
|
|
|
|
|
class Case(Expression):
|
|
"""
|
|
An SQL searched CASE expression:
|
|
|
|
CASE
|
|
WHEN n > 0
|
|
THEN 'positive'
|
|
WHEN n < 0
|
|
THEN 'negative'
|
|
ELSE 'zero'
|
|
END
|
|
"""
|
|
template = 'CASE %(cases)s ELSE %(default)s END'
|
|
case_joiner = ' '
|
|
|
|
def __init__(self, *cases, **extra):
|
|
if not all(isinstance(case, When) for case in cases):
|
|
raise TypeError("Positional arguments must all be When objects.")
|
|
default = extra.pop('default', None)
|
|
output_field = extra.pop('output_field', None)
|
|
super(Case, self).__init__(output_field)
|
|
self.cases = list(cases)
|
|
self.default = self._parse_expressions(default)[0]
|
|
|
|
def __str__(self):
|
|
return "CASE %s, ELSE %r" % (', '.join(str(c) for c in self.cases), self.default)
|
|
|
|
def __repr__(self):
|
|
return "<%s: %s>" % (self.__class__.__name__, self)
|
|
|
|
def get_source_expressions(self):
|
|
return self.cases + [self.default]
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.cases = exprs[:-1]
|
|
self.default = exprs[-1]
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
c = self.copy()
|
|
c.is_summary = summarize
|
|
for pos, case in enumerate(c.cases):
|
|
c.cases[pos] = case.resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
c.default = c.default.resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
return c
|
|
|
|
def as_sql(self, compiler, connection, template=None, extra=None):
|
|
connection.ops.check_expression_support(self)
|
|
if not self.cases:
|
|
return compiler.compile(self.default)
|
|
template_params = dict(extra) if extra else {}
|
|
case_parts = []
|
|
sql_params = []
|
|
for case in self.cases:
|
|
case_sql, case_params = compiler.compile(case)
|
|
case_parts.append(case_sql)
|
|
sql_params.extend(case_params)
|
|
template_params['cases'] = self.case_joiner.join(case_parts)
|
|
default_sql, default_params = compiler.compile(self.default)
|
|
template_params['default'] = default_sql
|
|
sql_params.extend(default_params)
|
|
template = template or self.template
|
|
sql = template % template_params
|
|
if self._output_field_or_none is not None:
|
|
sql = connection.ops.unification_cast_sql(self.output_field) % sql
|
|
return sql, sql_params
|
|
|
|
|
|
class Date(Expression):
|
|
"""
|
|
Add a date selection column.
|
|
"""
|
|
def __init__(self, lookup, lookup_type):
|
|
super(Date, self).__init__(output_field=fields.DateField())
|
|
self.lookup = lookup
|
|
self.col = None
|
|
self.lookup_type = lookup_type
|
|
|
|
def __repr__(self):
|
|
return "{}({}, {})".format(self.__class__.__name__, self.lookup, self.lookup_type)
|
|
|
|
def get_source_expressions(self):
|
|
return [self.col]
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.col, = exprs
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
copy = self.copy()
|
|
copy.col = query.resolve_ref(self.lookup, allow_joins, reuse, summarize)
|
|
field = copy.col.output_field
|
|
assert isinstance(field, fields.DateField), "%r isn't a DateField." % field.name
|
|
if settings.USE_TZ:
|
|
assert not isinstance(field, fields.DateTimeField), (
|
|
"%r is a DateTimeField, not a DateField." % field.name
|
|
)
|
|
return copy
|
|
|
|
def as_sql(self, compiler, connection):
|
|
sql, params = self.col.as_sql(compiler, connection)
|
|
assert not(params)
|
|
return connection.ops.date_trunc_sql(self.lookup_type, sql), []
|
|
|
|
def copy(self):
|
|
copy = super(Date, self).copy()
|
|
copy.lookup = self.lookup
|
|
copy.lookup_type = self.lookup_type
|
|
return copy
|
|
|
|
def convert_value(self, value, expression, connection, context):
|
|
if isinstance(value, datetime.datetime):
|
|
value = value.date()
|
|
return value
|
|
|
|
|
|
class DateTime(Expression):
|
|
"""
|
|
Add a datetime selection column.
|
|
"""
|
|
def __init__(self, lookup, lookup_type, tzinfo):
|
|
super(DateTime, self).__init__(output_field=fields.DateTimeField())
|
|
self.lookup = lookup
|
|
self.col = None
|
|
self.lookup_type = lookup_type
|
|
if tzinfo is None:
|
|
self.tzname = None
|
|
else:
|
|
self.tzname = timezone._get_timezone_name(tzinfo)
|
|
self.tzinfo = tzinfo
|
|
|
|
def __repr__(self):
|
|
return "{}({}, {}, {})".format(
|
|
self.__class__.__name__, self.lookup, self.lookup_type, self.tzinfo)
|
|
|
|
def get_source_expressions(self):
|
|
return [self.col]
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.col, = exprs
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
copy = self.copy()
|
|
copy.col = query.resolve_ref(self.lookup, allow_joins, reuse, summarize)
|
|
field = copy.col.output_field
|
|
assert isinstance(field, fields.DateTimeField), (
|
|
"%r isn't a DateTimeField." % field.name
|
|
)
|
|
return copy
|
|
|
|
def as_sql(self, compiler, connection):
|
|
sql, params = self.col.as_sql(compiler, connection)
|
|
assert not(params)
|
|
return connection.ops.datetime_trunc_sql(self.lookup_type, sql, self.tzname)
|
|
|
|
def copy(self):
|
|
copy = super(DateTime, self).copy()
|
|
copy.lookup = self.lookup
|
|
copy.lookup_type = self.lookup_type
|
|
copy.tzname = self.tzname
|
|
return copy
|
|
|
|
def convert_value(self, value, expression, connection, context):
|
|
if settings.USE_TZ:
|
|
if value is None:
|
|
raise ValueError(
|
|
"Database returned an invalid value in QuerySet.datetimes(). "
|
|
"Are time zone definitions for your database and pytz installed?"
|
|
)
|
|
value = value.replace(tzinfo=None)
|
|
value = timezone.make_aware(value, self.tzinfo)
|
|
return value
|
|
|
|
|
|
class OrderBy(BaseExpression):
|
|
template = '%(expression)s %(ordering)s'
|
|
|
|
def __init__(self, expression, descending=False):
|
|
self.descending = descending
|
|
if not hasattr(expression, 'resolve_expression'):
|
|
raise ValueError('expression must be an expression type')
|
|
self.expression = expression
|
|
|
|
def __repr__(self):
|
|
return "{}({}, descending={})".format(
|
|
self.__class__.__name__, self.expression, self.descending)
|
|
|
|
def set_source_expressions(self, exprs):
|
|
self.expression = exprs[0]
|
|
|
|
def get_source_expressions(self):
|
|
return [self.expression]
|
|
|
|
def as_sql(self, compiler, connection):
|
|
connection.ops.check_expression_support(self)
|
|
expression_sql, params = compiler.compile(self.expression)
|
|
placeholders = {'expression': expression_sql}
|
|
placeholders['ordering'] = 'DESC' if self.descending else 'ASC'
|
|
return (self.template % placeholders).rstrip(), params
|
|
|
|
def get_group_by_cols(self):
|
|
cols = []
|
|
for source in self.get_source_expressions():
|
|
cols.extend(source.get_group_by_cols())
|
|
return cols
|
|
|
|
def reverse_ordering(self):
|
|
self.descending = not self.descending
|
|
return self
|
|
|
|
def asc(self):
|
|
self.descending = False
|
|
|
|
def desc(self):
|
|
self.descending = True
|