django1/django/contrib/gis/db/backends/postgis/schema.py

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from django.db.backends.postgresql.schema import DatabaseSchemaEditor
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class PostGISSchemaEditor(DatabaseSchemaEditor):
geom_index_type = 'GIST'
geom_index_ops_nd = 'GIST_GEOMETRY_OPS_ND'
rast_index_wrapper = 'ST_ConvexHull(%s)'
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sql_add_spatial_index = "CREATE INDEX %(index)s ON %(table)s USING %(index_type)s (%(column)s %(ops)s)"
sql_clear_geometry_columns = "DELETE FROM geometry_columns WHERE f_table_name = %(table)s"
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def __init__(self, *args, **kwargs):
super(PostGISSchemaEditor, self).__init__(*args, **kwargs)
self.geometry_sql = []
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def geo_quote_name(self, name):
return self.connection.ops.geo_quote_name(name)
def column_sql(self, model, field, include_default=False):
from django.contrib.gis.db.models.fields import BaseSpatialField
if not isinstance(field, BaseSpatialField):
return super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
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column_sql = super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
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if field.spatial_index:
# Spatial indexes created the same way for both Geometry and
# Geography columns.
field_column = self.quote_name(field.column)
if field.geom_type == 'RASTER':
# For raster fields, wrap index creation SQL statement with ST_ConvexHull.
# Indexes on raster columns are based on the convex hull of the raster.
field_column = self.rast_index_wrapper % field_column
index_ops = ''
elif field.geography:
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index_ops = ''
else:
# Use either "nd" ops which are fast on multidimensional cases
# or just plain gist index for the 2d case.
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if field.dim > 2:
index_ops = self.geom_index_ops_nd
else:
index_ops = ''
self.geometry_sql.append(
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self.sql_add_spatial_index % {
"index": self.quote_name('%s_%s_id' % (model._meta.db_table, field.column)),
"table": self.quote_name(model._meta.db_table),
"column": field_column,
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"index_type": self.geom_index_type,
"ops": index_ops,
}
)
return column_sql
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def create_model(self, model):
super(PostGISSchemaEditor, self).create_model(model)
# Create geometry columns
for sql in self.geometry_sql:
self.execute(sql)
self.geometry_sql = []
def delete_model(self, model):
super(PostGISSchemaEditor, self).delete_model(model)
self.execute(self.sql_clear_geometry_columns % {
"table": self.geo_quote_name(model._meta.db_table),
})
def add_field(self, model, field):
super(PostGISSchemaEditor, self).add_field(model, field)
# Create geometry columns
for sql in self.geometry_sql:
self.execute(sql)
self.geometry_sql = []