Class BaseExpression

Declaration

Documentation

Methods

• ▷ def __eq__(self, other)

  source link
• ▶ def __getstate__(self)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Subquery
• ▷ def __hash__(self)

  source link
• ▶ def __init__(self, output_field=None)

  source link

  Overrides

  This method is overriden in:

  • django.contrib.postgres.search.SearchConfig
  • django.contrib.postgres.fields.ranges.RangeBoundary
  • django.db.models.expressions.CombinedExpression
  • django.db.models.expressions.Func
  • django.db.models.expressions.Value
  • django.db.models.expressions.RawSQL
  • django.db.models.expressions.Col
  • django.db.models.expressions.Ref
  • django.db.models.expressions.ExpressionWrapper
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
  • django.db.models.expressions.OrderBy
  • django.db.models.expressions.Window
  • django.db.models.expressions.WindowFrame
  • django.db.models.sql.query.Query
• ▶ def as_sql(self, compiler, connection)

  Responsible for returning a (sql, [params]) tuple to be included in the current query.

  source link

  Different backends can provide their own implementation, by
  providing an `as_{vendor}` method and patching the Expression:
  
  ```
  def override_as_sql(self, compiler, connection):
      # custom logic
      return super().as_sql(compiler, connection)
  setattr(Expression, 'as_' + connection.vendor, override_as_sql)
  ```
  
  Arguments:
   * compiler: the query compiler responsible for generating the query.
     Must have a compile method, returning a (sql, [params]) tuple.
     Calling compiler(value) will return a quoted `value`.
  
   * connection: the database connection used for the current query.
  
  Return: (sql, params)
    Where `sql` is a string containing ordered sql parameters to be
    replaced with the elements of the list `params`.

  Overrides

  This method is overriden in:

  • django.contrib.postgres.search.SearchConfig
  • django.contrib.postgres.fields.ranges.RangeBoundary
  • django.db.models.expressions.CombinedExpression
  • django.db.models.expressions.Func
  • django.db.models.expressions.Value
  • django.db.models.expressions.RawSQL
  • django.db.models.expressions.Star
  • django.db.models.expressions.Col
  • django.db.models.expressions.Ref
  • django.db.models.expressions.ExpressionWrapper
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
  • django.db.models.expressions.OrderBy
  • django.db.models.expressions.Window
  • django.db.models.expressions.WindowFrame
  • django.db.models.sql.query.Query
• ▶ def asc(self, **kwargs)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.OrderBy
• ▷ def conditional(self) @property

  @property
  def conditional(self)

  source link
• ▷ def contains_aggregate(self) @cached_property

  @cached_property
  def contains_aggregate(self)

  source link
• ▷ def contains_column_references(self) @cached_property

  @cached_property
  def contains_column_references(self)

  source link
• ▷ def contains_over_clause(self) @cached_property

  @cached_property
  def contains_over_clause(self)

  source link
• ▶ def convert_value(self) @cached_property

  Expressions provide their own converters because users have the option of manually specifying the output_field which may be a different type from the one the database returns.

  @cached_property
  def convert_value(self)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.aggregates.Count
  • django.db.models.functions.datetime.TruncBase
• ▶ def copy(self)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Func
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
• ▶ def desc(self, **kwargs)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.OrderBy
• ▷ def field(self) @property

  @property
  def field(self)

  source link
• ▷ def flatten(self)

  Recursively yield this expression and all subexpressions, in depth-first order.

  source link
• ▶ def get_db_converters(self, connection)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Col
• ▶ def get_group_by_cols(self, alias=None)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Value
  • django.db.models.expressions.RawSQL
  • django.db.models.expressions.Col
  • django.db.models.expressions.Ref
  • django.db.models.expressions.ExpressionWrapper
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
  • django.db.models.expressions.OrderBy
  • django.db.models.expressions.Window
  • django.db.models.expressions.WindowFrame
  • django.db.models.aggregates.Aggregate
  • django.db.models.functions.math.Random
• ▷ def get_lookup(self, lookup)

  source link
• ▶ def get_source_expressions(self)

  source link

  Overrides

  This method is overriden in:

  • django.contrib.postgres.search.SearchConfig
  • django.db.models.expressions.CombinedExpression
  • django.db.models.expressions.Func
  • django.db.models.expressions.Ref
  • django.db.models.expressions.ExpressionWrapper
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
  • django.db.models.expressions.OrderBy
  • django.db.models.expressions.Window
  • django.db.models.expressions.WindowFrame
• ▶ def get_source_fields(self)

  Return the underlying field types used by this aggregate.

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.When
  • django.db.models.aggregates.Aggregate
• ▷ def get_transform(self, name)

  source link
• ▶ def identity(self) @cached_property

  @cached_property
  def identity(self)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.sql.query.Query
• ▶ def output_field(self) @cached_property

  Return the output type of this expressions.

  @cached_property
  def output_field(self)

  source link

  Overrides

  This method is overriden in:

  • django.contrib.gis.db.backends.postgis.operations.ST_Polygon
  • django.contrib.gis.db.models.functions.GeomOutputGeoFunc
  • django.contrib.gis.db.models.functions.Area
  • django.contrib.postgres.fields.ranges.RangeStartsWith
  • django.contrib.postgres.fields.ranges.RangeEndsWith
  • django.contrib.postgres.fields.array.IndexTransform
  • django.db.models.sql.query.Query
• ▶ def relabeled_clone(self, change_map)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Col
  • django.db.models.expressions.Ref
  • django.db.models.sql.query.Query
• ▶ def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False)

  Provide the chance to do any preprocessing or validation before being added to the query.

  source link

  Arguments:
   * query: the backend query implementation
   * allow_joins: boolean allowing or denying use of joins
     in this query
   * reuse: a set of reusable joins for multijoins
   * summarize: a terminal aggregate clause
   * for_save: whether this expression about to be used in a save or update
  
  Return: an Expression to be added to the query.

  Overrides

  This method is overriden in:

  • django.db.models.expressions.CombinedExpression
  • django.db.models.expressions.Func
  • django.db.models.expressions.Value
  • django.db.models.expressions.RawSQL
  • django.db.models.expressions.Ref
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.sql.query.Query
• ▶ def reverse_ordering(self)

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.OrderBy
• ▶ def select_format(self, compiler, sql, params)

  Custom format for select clauses. For example, EXISTS expressions need to be wrapped in CASE WHEN on Oracle.

  source link

  Overrides

  This method is overriden in:

  • django.db.models.expressions.Exists
• ▶ def set_source_expressions(self, exprs)

  source link

  Overrides

  This method is overriden in:

  • django.contrib.postgres.search.SearchConfig
  • django.db.models.expressions.CombinedExpression
  • django.db.models.expressions.Func
  • django.db.models.expressions.Ref
  • django.db.models.expressions.ExpressionWrapper
  • django.db.models.expressions.When
  • django.db.models.expressions.Case
  • django.db.models.expressions.Subquery
  • django.db.models.expressions.OrderBy
  • django.db.models.expressions.Window
  • django.db.models.expressions.WindowFrame

Subclasses

• django.db.models.expressions.Expression
• django.db.models.expressions.OrderBy
• django.db.models.sql.query.Query

Reexports

• Imported in django.db.models.sql.query.

Generated by nedoc v0.9 at 2020-12-29 14:04