/build/lib.linux-x86_64-2.7/django/contrib/gis/db/models/sql/compiler.py
Python | 293 lines | 240 code | 10 blank | 43 comment | 22 complexity | 80dea39f68d8790d9a5954c6551f6227 MD5 | raw file
Possible License(s): BSD-3-Clause
- from itertools import izip
- from django.db.backends.util import truncate_name, typecast_timestamp
- from django.db.models.sql import compiler
- from django.db.models.sql.constants import TABLE_NAME, MULTI
- SQLCompiler = compiler.SQLCompiler
- class GeoSQLCompiler(compiler.SQLCompiler):
- def get_columns(self, with_aliases=False):
- """
- Return the list of columns to use in the select statement. If no
- columns have been specified, returns all columns relating to fields in
- the model.
- If 'with_aliases' is true, any column names that are duplicated
- (without the table names) are given unique aliases. This is needed in
- some cases to avoid ambiguitity with nested queries.
- This routine is overridden from Query to handle customized selection of
- geometry columns.
- """
- qn = self.quote_name_unless_alias
- qn2 = self.connection.ops.quote_name
- result = ['(%s) AS %s' % (self.get_extra_select_format(alias) % col[0], qn2(alias))
- for alias, col in self.query.extra_select.iteritems()]
- aliases = set(self.query.extra_select.keys())
- if with_aliases:
- col_aliases = aliases.copy()
- else:
- col_aliases = set()
- if self.query.select:
- only_load = self.deferred_to_columns()
- # This loop customized for GeoQuery.
- for col, field in izip(self.query.select, self.query.select_fields):
- if isinstance(col, (list, tuple)):
- alias, column = col
- table = self.query.alias_map[alias][TABLE_NAME]
- if table in only_load and column not in only_load[table]:
- continue
- r = self.get_field_select(field, alias, column)
- if with_aliases:
- if col[1] in col_aliases:
- c_alias = 'Col%d' % len(col_aliases)
- result.append('%s AS %s' % (r, c_alias))
- aliases.add(c_alias)
- col_aliases.add(c_alias)
- else:
- result.append('%s AS %s' % (r, qn2(col[1])))
- aliases.add(r)
- col_aliases.add(col[1])
- else:
- result.append(r)
- aliases.add(r)
- col_aliases.add(col[1])
- else:
- result.append(col.as_sql(qn, self.connection))
- if hasattr(col, 'alias'):
- aliases.add(col.alias)
- col_aliases.add(col.alias)
- elif self.query.default_cols:
- cols, new_aliases = self.get_default_columns(with_aliases,
- col_aliases)
- result.extend(cols)
- aliases.update(new_aliases)
- max_name_length = self.connection.ops.max_name_length()
- result.extend([
- '%s%s' % (
- self.get_extra_select_format(alias) % aggregate.as_sql(qn, self.connection),
- alias is not None
- and ' AS %s' % qn(truncate_name(alias, max_name_length))
- or ''
- )
- for alias, aggregate in self.query.aggregate_select.items()
- ])
- # This loop customized for GeoQuery.
- for (table, col), field in izip(self.query.related_select_cols, self.query.related_select_fields):
- r = self.get_field_select(field, table, col)
- if with_aliases and col in col_aliases:
- c_alias = 'Col%d' % len(col_aliases)
- result.append('%s AS %s' % (r, c_alias))
- aliases.add(c_alias)
- col_aliases.add(c_alias)
- else:
- result.append(r)
- aliases.add(r)
- col_aliases.add(col)
- self._select_aliases = aliases
- return result
- def get_default_columns(self, with_aliases=False, col_aliases=None,
- start_alias=None, opts=None, as_pairs=False, local_only=False):
- """
- Computes the default columns for selecting every field in the base
- model. Will sometimes be called to pull in related models (e.g. via
- select_related), in which case "opts" and "start_alias" will be given
- to provide a starting point for the traversal.
- Returns a list of strings, quoted appropriately for use in SQL
- directly, as well as a set of aliases used in the select statement (if
- 'as_pairs' is True, returns a list of (alias, col_name) pairs instead
- of strings as the first component and None as the second component).
- This routine is overridden from Query to handle customized selection of
- geometry columns.
- """
- result = []
- if opts is None:
- opts = self.query.model._meta
- aliases = set()
- only_load = self.deferred_to_columns()
- # Skip all proxy to the root proxied model
- proxied_model = opts.concrete_model
- if start_alias:
- seen = {None: start_alias}
- for field, model in opts.get_fields_with_model():
- if local_only and model is not None:
- continue
- if start_alias:
- try:
- alias = seen[model]
- except KeyError:
- if model is proxied_model:
- alias = start_alias
- else:
- link_field = opts.get_ancestor_link(model)
- alias = self.query.join((start_alias, model._meta.db_table,
- link_field.column, model._meta.pk.column))
- seen[model] = alias
- else:
- # If we're starting from the base model of the queryset, the
- # aliases will have already been set up in pre_sql_setup(), so
- # we can save time here.
- alias = self.query.included_inherited_models[model]
- table = self.query.alias_map[alias][TABLE_NAME]
- if table in only_load and field.column not in only_load[table]:
- continue
- if as_pairs:
- result.append((alias, field.column))
- aliases.add(alias)
- continue
- # This part of the function is customized for GeoQuery. We
- # see if there was any custom selection specified in the
- # dictionary, and set up the selection format appropriately.
- field_sel = self.get_field_select(field, alias)
- if with_aliases and field.column in col_aliases:
- c_alias = 'Col%d' % len(col_aliases)
- result.append('%s AS %s' % (field_sel, c_alias))
- col_aliases.add(c_alias)
- aliases.add(c_alias)
- else:
- r = field_sel
- result.append(r)
- aliases.add(r)
- if with_aliases:
- col_aliases.add(field.column)
- return result, aliases
- def resolve_columns(self, row, fields=()):
- """
- This routine is necessary so that distances and geometries returned
- from extra selection SQL get resolved appropriately into Python
- objects.
- """
- values = []
- aliases = self.query.extra_select.keys()
- # Have to set a starting row number offset that is used for
- # determining the correct starting row index -- needed for
- # doing pagination with Oracle.
- rn_offset = 0
- if self.connection.ops.oracle:
- if self.query.high_mark is not None or self.query.low_mark: rn_offset = 1
- index_start = rn_offset + len(aliases)
- # Converting any extra selection values (e.g., geometries and
- # distance objects added by GeoQuerySet methods).
- values = [self.query.convert_values(v,
- self.query.extra_select_fields.get(a, None),
- self.connection)
- for v, a in izip(row[rn_offset:index_start], aliases)]
- if self.connection.ops.oracle or getattr(self.query, 'geo_values', False):
- # We resolve the rest of the columns if we're on Oracle or if
- # the `geo_values` attribute is defined.
- for value, field in map(None, row[index_start:], fields):
- values.append(self.query.convert_values(value, field, self.connection))
- else:
- values.extend(row[index_start:])
- return tuple(values)
- #### Routines unique to GeoQuery ####
- def get_extra_select_format(self, alias):
- sel_fmt = '%s'
- if hasattr(self.query, 'custom_select') and alias in self.query.custom_select:
- sel_fmt = sel_fmt % self.query.custom_select[alias]
- return sel_fmt
- def get_field_select(self, field, alias=None, column=None):
- """
- Returns the SELECT SQL string for the given field. Figures out
- if any custom selection SQL is needed for the column The `alias`
- keyword may be used to manually specify the database table where
- the column exists, if not in the model associated with this
- `GeoQuery`. Similarly, `column` may be used to specify the exact
- column name, rather than using the `column` attribute on `field`.
- """
- sel_fmt = self.get_select_format(field)
- if field in self.query.custom_select:
- field_sel = sel_fmt % self.query.custom_select[field]
- else:
- field_sel = sel_fmt % self._field_column(field, alias, column)
- return field_sel
- def get_select_format(self, fld):
- """
- Returns the selection format string, depending on the requirements
- of the spatial backend. For example, Oracle and MySQL require custom
- selection formats in order to retrieve geometries in OGC WKT. For all
- other fields a simple '%s' format string is returned.
- """
- if self.connection.ops.select and hasattr(fld, 'geom_type'):
- # This allows operations to be done on fields in the SELECT,
- # overriding their values -- used by the Oracle and MySQL
- # spatial backends to get database values as WKT, and by the
- # `transform` method.
- sel_fmt = self.connection.ops.select
- # Because WKT doesn't contain spatial reference information,
- # the SRID is prefixed to the returned WKT to ensure that the
- # transformed geometries have an SRID different than that of the
- # field -- this is only used by `transform` for Oracle and
- # SpatiaLite backends.
- if self.query.transformed_srid and ( self.connection.ops.oracle or
- self.connection.ops.spatialite ):
- sel_fmt = "'SRID=%d;'||%s" % (self.query.transformed_srid, sel_fmt)
- else:
- sel_fmt = '%s'
- return sel_fmt
- # Private API utilities, subject to change.
- def _field_column(self, field, table_alias=None, column=None):
- """
- Helper function that returns the database column for the given field.
- The table and column are returned (quoted) in the proper format, e.g.,
- `"geoapp_city"."point"`. If `table_alias` is not specified, the
- database table associated with the model of this `GeoQuery` will be
- used. If `column` is specified, it will be used instead of the value
- in `field.column`.
- """
- if table_alias is None: table_alias = self.query.model._meta.db_table
- return "%s.%s" % (self.quote_name_unless_alias(table_alias),
- self.connection.ops.quote_name(column or field.column))
- class SQLInsertCompiler(compiler.SQLInsertCompiler, GeoSQLCompiler):
- pass
- class SQLDeleteCompiler(compiler.SQLDeleteCompiler, GeoSQLCompiler):
- pass
- class SQLUpdateCompiler(compiler.SQLUpdateCompiler, GeoSQLCompiler):
- pass
- class SQLAggregateCompiler(compiler.SQLAggregateCompiler, GeoSQLCompiler):
- pass
- class SQLDateCompiler(compiler.SQLDateCompiler, GeoSQLCompiler):
- """
- This is overridden for GeoDjango to properly cast date columns, since
- `GeoQuery.resolve_columns` is used for spatial values.
- See #14648, #16757.
- """
- def results_iter(self):
- if self.connection.ops.oracle:
- from django.db.models.fields import DateTimeField
- fields = [DateTimeField()]
- else:
- needs_string_cast = self.connection.features.needs_datetime_string_cast
- offset = len(self.query.extra_select)
- for rows in self.execute_sql(MULTI):
- for row in rows:
- date = row[offset]
- if self.connection.ops.oracle:
- date = self.resolve_columns(row, fields)[offset]
- elif needs_string_cast:
- date = typecast_timestamp(str(date))
- yield date