113 lines
4.7 KiB
Python
113 lines
4.7 KiB
Python
from django.db.backends.postgresql_psycopg2.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 = 'GIST_GEOMETRY_OPS'
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geom_index_ops_nd = 'GIST_GEOMETRY_OPS_ND'
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sql_add_geometry_column = "SELECT AddGeometryColumn(%(table)s, %(column)s, %(srid)s, %(geom_type)s, %(dim)s)"
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sql_drop_geometry_column = "SELECT DropGeometryColumn(%(table)s, %(column)s)"
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sql_alter_geometry_column_not_null = "ALTER TABLE %(table)s ALTER COLUMN %(column)s SET NOT NULL"
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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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sql_clear_geometry_columns = "DELETE FROM geometry_columns WHERE f_table_name = %(table)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 GeometryField
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if not isinstance(field, GeometryField):
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return super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
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if field.geography or self.connection.ops.geometry:
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# Geography and Geometry (PostGIS 2.0+) columns are
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# created normally.
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column_sql = super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
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else:
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column_sql = None, None
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# Geometry columns are created by the `AddGeometryColumn`
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# stored procedure.
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self.geometry_sql.append(
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self.sql_add_geometry_column % {
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"table": self.geo_quote_name(model._meta.db_table),
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"column": self.geo_quote_name(field.column),
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"srid": field.srid,
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"geom_type": self.geo_quote_name(field.geom_type),
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"dim": field.dim,
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}
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)
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if not field.null:
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self.geometry_sql.append(
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self.sql_alter_geometry_column_not_null % {
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"table": self.quote_name(model._meta.db_table),
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"column": self.quote_name(field.column),
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}
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)
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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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# PostGIS 2.0 does not support GIST_GEOMETRY_OPS. So, on 1.5
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# we use GIST_GEOMETRY_OPS, on 2.0 we use either "nd" ops
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# which are fast on multidimensional cases, or just plain
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# gist index for the 2d case.
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if field.geography:
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index_ops = ''
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elif self.connection.ops.geometry:
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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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else:
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index_ops = self.geom_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": self.quote_name(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 delete_model(self, model):
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super(PostGISSchemaEditor, self).delete_model(model)
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self.execute(self.sql_clear_geometry_columns % {
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"table": self.geo_quote_name(model._meta.db_table),
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})
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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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def remove_field(self, model, field):
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from django.contrib.gis.db.models.fields import GeometryField
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if not isinstance(field, GeometryField) or \
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self.connection.ops.spatial_version > (2, 0) or \
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field.geography:
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super(PostGISSchemaEditor, self).remove_field(model, field)
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else:
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self.execute(
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self.sql_drop_geometry_column % {
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"table": self.geo_quote_name(model._meta.db_table),
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"column": self.geo_quote_name(field.column),
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}
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)
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