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django1/django/contrib/gis/db/backend/postgis/query.py

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"""
This module contains the spatial lookup types, and the get_geo_where_clause()
routine for PostGIS.
"""
import re
from decimal import Decimal
from django.db import connection
from django.contrib.gis.measure import Distance
from django.contrib.gis.db.backend.postgis.management import postgis_version_tuple
from django.contrib.gis.db.backend.util import SpatialOperation, SpatialFunction
qn = connection.ops.quote_name
# Getting the PostGIS version information
POSTGIS_VERSION, MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2 = postgis_version_tuple()
# The supported PostGIS versions.
# TODO: Confirm tests with PostGIS versions 1.1.x -- should work.
# Versions <= 1.0.x do not use GEOS C API, and will not be supported.
if MAJOR_VERSION != 1 or (MAJOR_VERSION == 1 and MINOR_VERSION1 < 1):
raise Exception('PostGIS version %s not supported.' % POSTGIS_VERSION)
# Versions of PostGIS >= 1.2.2 changed their naming convention to be
# 'SQL-MM-centric' to conform with the ISO standard. Practically, this
# means that 'ST_' prefixes geometry function names.
GEOM_FUNC_PREFIX = ''
if MAJOR_VERSION >= 1:
if (MINOR_VERSION1 > 2 or
(MINOR_VERSION1 == 2 and MINOR_VERSION2 >= 2)):
GEOM_FUNC_PREFIX = 'ST_'
def get_func(func): return '%s%s' % (GEOM_FUNC_PREFIX, func)
# Custom selection not needed for PostGIS because GEOS geometries are
# instantiated directly from the HEXEWKB returned by default. If
# WKT is needed for some reason in the future, this value may be changed,
# e.g,, 'AsText(%s)'.
GEOM_SELECT = None
# Functions used by the GeoManager & GeoQuerySet
AREA = get_func('Area')
ASKML = get_func('AsKML')
ASGML = get_func('AsGML')
ASSVG = get_func('AsSVG')
CENTROID = get_func('Centroid')
DIFFERENCE = get_func('Difference')
DISTANCE = get_func('Distance')
DISTANCE_SPHERE = get_func('distance_sphere')
DISTANCE_SPHEROID = get_func('distance_spheroid')
ENVELOPE = get_func('Envelope')
EXTENT = get_func('extent')
GEOM_FROM_TEXT = get_func('GeomFromText')
GEOM_FROM_WKB = get_func('GeomFromWKB')
INTERSECTION = get_func('Intersection')
LENGTH = get_func('Length')
LENGTH_SPHEROID = get_func('length_spheroid')
MAKE_LINE = get_func('MakeLine')
MEM_SIZE = get_func('mem_size')
NUM_GEOM = get_func('NumGeometries')
NUM_POINTS = get_func('npoints')
PERIMETER = get_func('Perimeter')
POINT_ON_SURFACE = get_func('PointOnSurface')
SCALE = get_func('Scale')
SYM_DIFFERENCE = get_func('SymDifference')
TRANSFORM = get_func('Transform')
TRANSLATE = get_func('Translate')
# Special cases for union and KML methods.
if MINOR_VERSION1 < 3:
UNIONAGG = 'GeomUnion'
UNION = 'Union'
else:
UNIONAGG = 'ST_Union'
UNION = 'ST_Union'
if MINOR_VERSION1 == 1:
ASKML = False
else:
raise NotImplementedError('PostGIS versions < 1.0 are not supported.')
#### Classes used in constructing PostGIS spatial SQL ####
class PostGISOperator(SpatialOperation):
"For PostGIS operators (e.g. `&&`, `~`)."
def __init__(self, operator):
super(PostGISOperator, self).__init__(operator=operator, beg_subst='%s %s %%s')
class PostGISFunction(SpatialFunction):
"For PostGIS function calls (e.g., `ST_Contains(table, geom)`)."
def __init__(self, function, **kwargs):
super(PostGISFunction, self).__init__(get_func(function), **kwargs)
class PostGISFunctionParam(PostGISFunction):
"For PostGIS functions that take another parameter (e.g. DWithin, Relate)."
def __init__(self, func):
super(PostGISFunctionParam, self).__init__(func, end_subst=', %%s)')
class PostGISDistance(PostGISFunction):
"For PostGIS distance operations."
dist_func = 'Distance'
def __init__(self, operator):
super(PostGISDistance, self).__init__(self.dist_func, end_subst=') %s %s',
operator=operator, result='%%s')
class PostGISSpheroidDistance(PostGISFunction):
"For PostGIS spherical distance operations (using the spheroid)."
dist_func = 'distance_spheroid'
def __init__(self, operator):
# An extra parameter in `end_subst` is needed for the spheroid string.
super(PostGISSpheroidDistance, self).__init__(self.dist_func,
beg_subst='%s(%s, %%s, %%s',
end_subst=') %s %s',
operator=operator, result='%%s')
class PostGISSphereDistance(PostGISFunction):
"For PostGIS spherical distance operations."
dist_func = 'distance_sphere'
def __init__(self, operator):
super(PostGISSphereDistance, self).__init__(self.dist_func, end_subst=') %s %s',
operator=operator, result='%%s')
class PostGISRelate(PostGISFunctionParam):
"For PostGIS Relate(<geom>, <pattern>) calls."
pattern_regex = re.compile(r'^[012TF\*]{9}$')
def __init__(self, pattern):
if not self.pattern_regex.match(pattern):
raise ValueError('Invalid intersection matrix pattern "%s".' % pattern)
super(PostGISRelate, self).__init__('Relate')
#### Lookup type mapping dictionaries of PostGIS operations. ####
# PostGIS-specific operators. The commented descriptions of these
# operators come from Section 6.2.2 of the official PostGIS documentation.
POSTGIS_OPERATORS = {
# The "&<" operator returns true if A's bounding box overlaps or
# is to the left of B's bounding box.
'overlaps_left' : PostGISOperator('&<'),
# The "&>" operator returns true if A's bounding box overlaps or
# is to the right of B's bounding box.
'overlaps_right' : PostGISOperator('&>'),
# The "<<" operator returns true if A's bounding box is strictly
# to the left of B's bounding box.
'left' : PostGISOperator('<<'),
# The ">>" operator returns true if A's bounding box is strictly
# to the right of B's bounding box.
'right' : PostGISOperator('>>'),
# The "&<|" operator returns true if A's bounding box overlaps or
# is below B's bounding box.
'overlaps_below' : PostGISOperator('&<|'),
# The "|&>" operator returns true if A's bounding box overlaps or
# is above B's bounding box.
'overlaps_above' : PostGISOperator('|&>'),
# The "<<|" operator returns true if A's bounding box is strictly
# below B's bounding box.
'strictly_below' : PostGISOperator('<<|'),
# The "|>>" operator returns true if A's bounding box is strictly
# above B's bounding box.
'strictly_above' : PostGISOperator('|>>'),
# The "~=" operator is the "same as" operator. It tests actual
# geometric equality of two features. So if A and B are the same feature,
# vertex-by-vertex, the operator returns true.
'same_as' : PostGISOperator('~='),
'exact' : PostGISOperator('~='),
# The "@" operator returns true if A's bounding box is completely contained
# by B's bounding box.
'contained' : PostGISOperator('@'),
# The "~" operator returns true if A's bounding box completely contains
# by B's bounding box.
'bbcontains' : PostGISOperator('~'),
# The "&&" operator returns true if A's bounding box overlaps
# B's bounding box.
'bboverlaps' : PostGISOperator('&&'),
}
# For PostGIS >= 1.2.2 the following lookup types will do a bounding box query
# first before calling the more computationally expensive GEOS routines (called
# "inline index magic"):
# 'touches', 'crosses', 'contains', 'intersects', 'within', 'overlaps', and
# 'covers'.
POSTGIS_GEOMETRY_FUNCTIONS = {
'equals' : PostGISFunction('Equals'),
'disjoint' : PostGISFunction('Disjoint'),
'touches' : PostGISFunction('Touches'),
'crosses' : PostGISFunction('Crosses'),
'within' : PostGISFunction('Within'),
'overlaps' : PostGISFunction('Overlaps'),
'contains' : PostGISFunction('Contains'),
'intersects' : PostGISFunction('Intersects'),
'relate' : (PostGISRelate, basestring),
}
# Valid distance types and substitutions
dtypes = (Decimal, Distance, float, int, long)
def get_dist_ops(operator):
"Returns operations for both regular and spherical distances."
return (PostGISDistance(operator), PostGISSphereDistance(operator), PostGISSpheroidDistance(operator))
DISTANCE_FUNCTIONS = {
'distance_gt' : (get_dist_ops('>'), dtypes),
'distance_gte' : (get_dist_ops('>='), dtypes),
'distance_lt' : (get_dist_ops('<'), dtypes),
'distance_lte' : (get_dist_ops('<='), dtypes),
}
if GEOM_FUNC_PREFIX == 'ST_':
# The ST_DWithin, ST_CoveredBy, and ST_Covers routines become available in 1.2.2+
POSTGIS_GEOMETRY_FUNCTIONS.update(
{'coveredby' : PostGISFunction('CoveredBy'),
'covers' : PostGISFunction('Covers'),
})
DISTANCE_FUNCTIONS['dwithin'] = (PostGISFunctionParam('DWithin'), dtypes)
# Distance functions are a part of PostGIS geometry functions.
POSTGIS_GEOMETRY_FUNCTIONS.update(DISTANCE_FUNCTIONS)
# Any other lookup types that do not require a mapping.
MISC_TERMS = ['isnull']
# These are the PostGIS-customized QUERY_TERMS -- a list of the lookup types
# allowed for geographic queries.
POSTGIS_TERMS = POSTGIS_OPERATORS.keys() # Getting the operators first
POSTGIS_TERMS += POSTGIS_GEOMETRY_FUNCTIONS.keys() # Adding on the Geometry Functions
POSTGIS_TERMS += MISC_TERMS # Adding any other miscellaneous terms (e.g., 'isnull')
POSTGIS_TERMS = dict((term, None) for term in POSTGIS_TERMS) # Making a dictionary for fast lookups
# For checking tuple parameters -- not very pretty but gets job done.
def exactly_two(val): return val == 2
def two_to_three(val): return val >= 2 and val <=3
def num_params(lookup_type, val):
if lookup_type in DISTANCE_FUNCTIONS and lookup_type != 'dwithin': return two_to_three(val)
else: return exactly_two(val)
#### The `get_geo_where_clause` function for PostGIS. ####
def get_geo_where_clause(table_alias, name, lookup_type, geo_annot):
"Returns the SQL WHERE clause for use in PostGIS SQL construction."
# Getting the quoted field as `geo_col`.
geo_col = '%s.%s' % (qn(table_alias), qn(name))
if lookup_type in POSTGIS_OPERATORS:
# See if a PostGIS operator matches the lookup type.
return POSTGIS_OPERATORS[lookup_type].as_sql(geo_col)
elif lookup_type in POSTGIS_GEOMETRY_FUNCTIONS:
# See if a PostGIS geometry function matches the lookup type.
tmp = POSTGIS_GEOMETRY_FUNCTIONS[lookup_type]
# Lookup types that are tuples take tuple arguments, e.g., 'relate' and
# distance lookups.
if isinstance(tmp, tuple):
# First element of tuple is the PostGISOperation instance, and the
# second element is either the type or a tuple of acceptable types
# that may passed in as further parameters for the lookup type.
op, arg_type = tmp
# Ensuring that a tuple _value_ was passed in from the user
if not isinstance(geo_annot.value, (tuple, list)):
raise TypeError('Tuple required for `%s` lookup type.' % lookup_type)
# Number of valid tuple parameters depends on the lookup type.
nparams = len(geo_annot.value)
if not num_params(lookup_type, nparams):
raise ValueError('Incorrect number of parameters given for `%s` lookup type.' % lookup_type)
# Ensuring the argument type matches what we expect.
if not isinstance(geo_annot.value[1], arg_type):
raise TypeError('Argument type should be %s, got %s instead.' % (arg_type, type(geo_annot.value[1])))
# For lookup type `relate`, the op instance is not yet created (has
# to be instantiated here to check the pattern parameter).
if lookup_type == 'relate':
op = op(geo_annot.value[1])
elif lookup_type in DISTANCE_FUNCTIONS and lookup_type != 'dwithin':
if geo_annot.geodetic:
# Geodetic distances are only availble from Points to PointFields.
if geo_annot.geom_type != 'POINT':
raise TypeError('PostGIS spherical operations are only valid on PointFields.')
if geo_annot.value[0].geom_typeid != 0:
raise TypeError('PostGIS geometry distance parameter is required to be of type Point.')
# Setting up the geodetic operation appropriately.
if nparams == 3 and geo_annot.value[2] == 'spheroid': op = op[2]
else: op = op[1]
else:
op = op[0]
else:
op = tmp
# Calling the `as_sql` function on the operation instance.
return op.as_sql(geo_col)
elif lookup_type == 'isnull':
# Handling 'isnull' lookup type
return "%s IS %sNULL" % (geo_col, (not geo_annot.value and 'NOT ' or ''))
raise TypeError("Got invalid lookup_type: %s" % repr(lookup_type))
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