189 lines
9.1 KiB
Python
189 lines
9.1 KiB
Python
"""
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This overrides the traditional `inspectdb` command so that geographic databases
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may be introspected.
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"""
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from django.core.management.commands.inspectdb import Command as InspectCommand
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from django.contrib.gis.db.backend import SpatialBackend
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class Command(InspectCommand):
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# Mapping from lower-case OGC type to the corresponding GeoDjango field.
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geofield_mapping = {'point' : 'PointField',
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'linestring' : 'LineStringField',
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'polygon' : 'PolygonField',
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'multipoint' : 'MultiPointField',
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'multilinestring' : 'MultiLineStringField',
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'multipolygon' : 'MultiPolygonField',
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'geometrycollection' : 'GeometryCollectionField',
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'geometry' : 'GeometryField',
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}
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def geometry_columns(self):
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"""
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Returns a datastructure of metadata information associated with the
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`geometry_columns` (or equivalent) table.
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"""
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# The `geo_cols` is a dictionary data structure that holds information
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# about any geographic columns in the database.
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geo_cols = {}
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def add_col(table, column, coldata):
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if table in geo_cols:
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# If table already has a geometry column.
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geo_cols[table][column] = coldata
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else:
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# Otherwise, create a dictionary indexed by column.
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geo_cols[table] = { column : coldata }
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if SpatialBackend.name == 'postgis':
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# PostGIS holds all geographic column information in the `geometry_columns` table.
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from django.contrib.gis.models import GeometryColumns
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for geo_col in GeometryColumns.objects.all():
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table = geo_col.f_table_name
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column = geo_col.f_geometry_column
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coldata = {'type' : geo_col.type, 'srid' : geo_col.srid, 'dim' : geo_col.coord_dimension}
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add_col(table, column, coldata)
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return geo_cols
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elif SpatialBackend.name == 'mysql':
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# On MySQL have to get all table metadata before hand; this means walking through
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# each table and seeing if any column types are spatial. Can't detect this with
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# `cursor.description` (what the introspection module does) because all spatial types
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# have the same integer type (255 for GEOMETRY).
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from django.db import connection
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cursor = connection.cursor()
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cursor.execute('SHOW TABLES')
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tables = cursor.fetchall();
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for table_tup in tables:
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table = table_tup[0]
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table_desc = cursor.execute('DESCRIBE `%s`' % table)
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col_info = cursor.fetchall()
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for column, typ, null, key, default, extra in col_info:
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if typ in self.geofield_mapping: add_col(table, column, {'type' : typ})
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return geo_cols
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else:
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# TODO: Oracle (has incomplete `geometry_columns` -- have to parse
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# SDO SQL to get specific type, SRID, and other information).
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raise NotImplementedError('Geographic database inspection not available.')
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def handle_inspection(self):
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"Overloaded from Django's version to handle geographic database tables."
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from django.db import connection
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import keyword
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geo_cols = self.geometry_columns()
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table2model = lambda table_name: table_name.title().replace('_', '')
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cursor = connection.cursor()
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yield "# This is an auto-generated Django model module."
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yield "# You'll have to do the following manually to clean this up:"
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yield "# * Rearrange models' order"
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yield "# * Make sure each model has one field with primary_key=True"
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yield "# Feel free to rename the models, but don't rename db_table values or field names."
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yield "#"
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yield "# Also note: You'll have to insert the output of 'django-admin.py sqlcustom [appname]'"
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yield "# into your database."
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yield ''
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yield 'from django.contrib.gis.db import models'
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yield ''
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for table_name in connection.introspection.get_table_list(cursor):
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# Getting the geographic table dictionary.
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geo_table = geo_cols.get(table_name, {})
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yield 'class %s(models.Model):' % table2model(table_name)
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try:
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relations = connection.introspection.get_relations(cursor, table_name)
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except NotImplementedError:
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relations = {}
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try:
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indexes = connection.introspection.get_indexes(cursor, table_name)
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except NotImplementedError:
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indexes = {}
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for i, row in enumerate(connection.introspection.get_table_description(cursor, table_name)):
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att_name, iatt_name = row[0].lower(), row[0]
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comment_notes = [] # Holds Field notes, to be displayed in a Python comment.
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extra_params = {} # Holds Field parameters such as 'db_column'.
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if ' ' in att_name:
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extra_params['db_column'] = att_name
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att_name = att_name.replace(' ', '')
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comment_notes.append('Field renamed to remove spaces.')
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if keyword.iskeyword(att_name):
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extra_params['db_column'] = att_name
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att_name += '_field'
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comment_notes.append('Field renamed because it was a Python reserved word.')
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if i in relations:
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rel_to = relations[i][1] == table_name and "'self'" or table2model(relations[i][1])
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field_type = 'ForeignKey(%s' % rel_to
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if att_name.endswith('_id'):
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att_name = att_name[:-3]
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else:
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extra_params['db_column'] = att_name
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else:
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if iatt_name in geo_table:
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## Customization for Geographic Columns ##
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geo_col = geo_table[iatt_name]
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field_type = self.geofield_mapping[geo_col['type'].lower()]
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# Adding extra keyword arguments for the SRID and dimension (if not defaults).
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dim, srid = geo_col.get('dim', 2), geo_col.get('srid', 4326)
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if dim != 2: extra_params['dim'] = dim
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if srid != 4326: extra_params['srid'] = srid
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else:
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try:
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field_type = connection.introspection.get_field_type(row[1], row)
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except KeyError:
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field_type = 'TextField'
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comment_notes.append('This field type is a guess.')
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# This is a hook for data_types_reverse to return a tuple of
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# (field_type, extra_params_dict).
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if type(field_type) is tuple:
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field_type, new_params = field_type
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extra_params.update(new_params)
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# Add max_length for all CharFields.
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if field_type == 'CharField' and row[3]:
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extra_params['max_length'] = row[3]
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if field_type == 'DecimalField':
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extra_params['max_digits'] = row[4]
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extra_params['decimal_places'] = row[5]
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# Add primary_key and unique, if necessary.
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column_name = extra_params.get('db_column', att_name)
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if column_name in indexes:
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if indexes[column_name]['primary_key']:
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extra_params['primary_key'] = True
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elif indexes[column_name]['unique']:
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extra_params['unique'] = True
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field_type += '('
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# Don't output 'id = meta.AutoField(primary_key=True)', because
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# that's assumed if it doesn't exist.
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if att_name == 'id' and field_type == 'AutoField(' and extra_params == {'primary_key': True}:
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continue
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# Add 'null' and 'blank', if the 'null_ok' flag was present in the
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# table description.
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if row[6]: # If it's NULL...
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extra_params['blank'] = True
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if not field_type in ('TextField(', 'CharField('):
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extra_params['null'] = True
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field_desc = '%s = models.%s' % (att_name, field_type)
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if extra_params:
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if not field_desc.endswith('('):
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field_desc += ', '
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field_desc += ', '.join(['%s=%r' % (k, v) for k, v in extra_params.items()])
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field_desc += ')'
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if comment_notes:
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field_desc += ' # ' + ' '.join(comment_notes)
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yield ' %s' % field_desc
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if table_name in geo_cols:
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yield ' objects = models.GeoManager()'
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yield ' class Meta:'
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yield ' db_table = %r' % table_name
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yield ''
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