django1/django/contrib/gis/management/commands/inspectdb.py

189 lines
9.1 KiB
Python

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