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