| from django.db import connection |
| from django.db.backends.util import truncate_name |
| from django.db.models.fields import Field # Django base Field class |
| from django.contrib.gis.db.backend.util import gqn |
| from django.contrib.gis.db.backend.oracle.query import TRANSFORM |
| |
| # Quotename & geographic quotename, respectively. |
| qn = connection.ops.quote_name |
| |
| class OracleSpatialField(Field): |
| """ |
| The backend-specific geographic field for Oracle Spatial. |
| """ |
| |
| empty_strings_allowed = False |
| |
| def __init__(self, extent=(-180.0, -90.0, 180.0, 90.0), tolerance=0.05, **kwargs): |
| """ |
| Oracle Spatial backend needs to have the extent -- for projected coordinate |
| systems _you must define the extent manually_, since the coordinates are |
| for geodetic systems. The `tolerance` keyword specifies the tolerance |
| for error (in meters), and defaults to 0.05 (5 centimeters). |
| """ |
| # Oracle Spatial specific keyword arguments. |
| self._extent = extent |
| self._tolerance = tolerance |
| # Calling the Django field initialization. |
| super(OracleSpatialField, self).__init__(**kwargs) |
| |
| def _add_geom(self, style, db_table): |
| """ |
| Adds this geometry column into the Oracle USER_SDO_GEOM_METADATA |
| table. |
| """ |
| |
| # Checking the dimensions. |
| # TODO: Add support for 3D geometries. |
| if self._dim != 2: |
| raise Exception('3D geometries not yet supported on Oracle Spatial backend.') |
| |
| # Constructing the SQL that will be used to insert information about |
| # the geometry column into the USER_GSDO_GEOM_METADATA table. |
| meta_sql = style.SQL_KEYWORD('INSERT INTO ') + \ |
| style.SQL_TABLE('USER_SDO_GEOM_METADATA') + \ |
| ' (%s, %s, %s, %s)\n ' % tuple(map(qn, ['TABLE_NAME', 'COLUMN_NAME', 'DIMINFO', 'SRID'])) + \ |
| style.SQL_KEYWORD(' VALUES ') + '(\n ' + \ |
| style.SQL_TABLE(gqn(db_table)) + ',\n ' + \ |
| style.SQL_FIELD(gqn(self.column)) + ',\n ' + \ |
| style.SQL_KEYWORD("MDSYS.SDO_DIM_ARRAY") + '(\n ' + \ |
| style.SQL_KEYWORD("MDSYS.SDO_DIM_ELEMENT") + \ |
| ("('LONG', %s, %s, %s),\n " % (self._extent[0], self._extent[2], self._tolerance)) + \ |
| style.SQL_KEYWORD("MDSYS.SDO_DIM_ELEMENT") + \ |
| ("('LAT', %s, %s, %s)\n ),\n" % (self._extent[1], self._extent[3], self._tolerance)) + \ |
| ' %s\n );' % self._srid |
| return meta_sql |
| |
| def _geom_index(self, style, db_table): |
| "Creates an Oracle Geometry index (R-tree) for this geometry field." |
| |
| # Getting the index name, Oracle doesn't allow object |
| # names > 30 characters. |
| idx_name = truncate_name('%s_%s_id' % (db_table, self.column), 30) |
| |
| sql = style.SQL_KEYWORD('CREATE INDEX ') + \ |
| style.SQL_TABLE(qn(idx_name)) + \ |
| style.SQL_KEYWORD(' ON ') + \ |
| style.SQL_TABLE(qn(db_table)) + '(' + \ |
| style.SQL_FIELD(qn(self.column)) + ') ' + \ |
| style.SQL_KEYWORD('INDEXTYPE IS ') + \ |
| style.SQL_TABLE('MDSYS.SPATIAL_INDEX') + ';' |
| return sql |
| |
| def post_create_sql(self, style, db_table): |
| """ |
| Returns SQL that will be executed after the model has been |
| created. |
| """ |
| # Getting the meta geometry information. |
| post_sql = self._add_geom(style, db_table) |
| |
| # Getting the geometric index for this Geometry column. |
| if self._index: |
| return (post_sql, self._geom_index(style, db_table)) |
| else: |
| return (post_sql,) |
| |
| def db_type(self): |
| "The Oracle geometric data type is MDSYS.SDO_GEOMETRY." |
| return 'MDSYS.SDO_GEOMETRY' |
| |
| def get_placeholder(self, value): |
| """ |
| Provides a proper substitution value for Geometries that are not in the |
| SRID of the field. Specifically, this routine will substitute in the |
| SDO_CS.TRANSFORM() function call. |
| """ |
| if value is None: |
| return '%s' |
| elif value.srid != self._srid: |
| # Adding Transform() to the SQL placeholder. |
| return '%s(SDO_GEOMETRY(%%s, %s), %s)' % (TRANSFORM, value.srid, self._srid) |
| else: |
| return 'SDO_GEOMETRY(%%s, %s)' % self._srid |