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d818e0c9b2
This is the result of Christopher Medrela's 2013 Summer of Code project. Thanks also to Preston Holmes, Tim Graham, Anssi Kääriäinen, Florian Apolloner, and Alex Gaynor for review notes along the way. Also: Fixes #8579, fixes #3055, fixes #19844.
247 lines
10 KiB
Python
247 lines
10 KiB
Python
from __future__ import unicode_literals
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from collections import OrderedDict
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import keyword
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import re
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from optparse import make_option
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from django.core.management.base import NoArgsCommand, CommandError
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from django.db import connections, DEFAULT_DB_ALIAS
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class Command(NoArgsCommand):
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help = "Introspects the database tables in the given database and outputs a Django model module."
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option_list = NoArgsCommand.option_list + (
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make_option('--database', action='store', dest='database',
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default=DEFAULT_DB_ALIAS, help='Nominates a database to '
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'introspect. Defaults to using the "default" database.'),
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)
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requires_system_checks = False
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db_module = 'django.db'
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def handle_noargs(self, **options):
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try:
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for line in self.handle_inspection(options):
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self.stdout.write("%s\n" % line)
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except NotImplementedError:
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raise CommandError("Database inspection isn't supported for the currently selected database backend.")
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def handle_inspection(self, options):
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connection = connections[options.get('database')]
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# 'table_name_filter' is a stealth option
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table_name_filter = options.get('table_name_filter')
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table2model = lambda table_name: table_name.title().replace('_', '').replace(' ', '').replace('-', '')
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strip_prefix = lambda s: s[1:] if s.startswith("u'") else s
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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 "# * Remove `managed = False` lines for those models you wish to give write DB access"
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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 [app_label]'"
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yield "# into your database."
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yield "from __future__ import unicode_literals"
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yield ''
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yield 'from %s import models' % self.db_module
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known_models = []
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for table_name in connection.introspection.table_names(cursor):
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if table_name_filter is not None and callable(table_name_filter):
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if not table_name_filter(table_name):
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continue
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yield ''
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yield ''
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yield 'class %s(models.Model):' % table2model(table_name)
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known_models.append(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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used_column_names = [] # Holds column names used in the table so far
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for i, row in enumerate(connection.introspection.get_table_description(cursor, table_name)):
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comment_notes = [] # Holds Field notes, to be displayed in a Python comment.
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extra_params = OrderedDict() # Holds Field parameters such as 'db_column'.
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column_name = row[0]
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is_relation = i in relations
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att_name, params, notes = self.normalize_col_name(
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column_name, used_column_names, is_relation)
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extra_params.update(params)
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comment_notes.extend(notes)
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used_column_names.append(att_name)
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# Add primary_key and unique, if necessary.
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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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if is_relation:
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rel_to = "self" if relations[i][1] == table_name else table2model(relations[i][1])
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if rel_to in known_models:
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field_type = 'ForeignKey(%s' % rel_to
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else:
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field_type = "ForeignKey('%s'" % rel_to
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else:
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# Calling `get_field_type` to get the field type string and any
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# additional paramters and notes.
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field_type, field_params, field_notes = self.get_field_type(connection, table_name, row)
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extra_params.update(field_params)
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comment_notes.extend(field_notes)
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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 extra_params == {'primary_key': True}:
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if field_type == 'AutoField(':
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continue
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elif field_type == 'IntegerField(' and not connection.features.can_introspect_autofield:
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comment_notes.append('AutoField?')
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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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if field_type == 'BooleanField(':
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field_type = 'NullBooleanField('
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else:
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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 = %s%s' % (
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att_name,
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# Custom fields will have a dotted path
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'' if '.' in field_type else 'models.',
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field_type,
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)
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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([
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'%s=%s' % (k, strip_prefix(repr(v)))
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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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for meta_line in self.get_meta(table_name):
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yield meta_line
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def normalize_col_name(self, col_name, used_column_names, is_relation):
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"""
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Modify the column name to make it Python-compatible as a field name
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"""
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field_params = {}
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field_notes = []
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new_name = col_name.lower()
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if new_name != col_name:
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field_notes.append('Field name made lowercase.')
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if is_relation:
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if new_name.endswith('_id'):
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new_name = new_name[:-3]
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else:
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field_params['db_column'] = col_name
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new_name, num_repl = re.subn(r'\W', '_', new_name)
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if num_repl > 0:
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field_notes.append('Field renamed to remove unsuitable characters.')
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if new_name.find('__') >= 0:
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while new_name.find('__') >= 0:
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new_name = new_name.replace('__', '_')
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if col_name.lower().find('__') >= 0:
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# Only add the comment if the double underscore was in the original name
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field_notes.append("Field renamed because it contained more than one '_' in a row.")
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if new_name.startswith('_'):
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new_name = 'field%s' % new_name
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field_notes.append("Field renamed because it started with '_'.")
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if new_name.endswith('_'):
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new_name = '%sfield' % new_name
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field_notes.append("Field renamed because it ended with '_'.")
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if keyword.iskeyword(new_name):
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new_name += '_field'
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field_notes.append('Field renamed because it was a Python reserved word.')
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if new_name[0].isdigit():
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new_name = 'number_%s' % new_name
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field_notes.append("Field renamed because it wasn't a valid Python identifier.")
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if new_name in used_column_names:
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num = 0
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while '%s_%d' % (new_name, num) in used_column_names:
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num += 1
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new_name = '%s_%d' % (new_name, num)
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field_notes.append('Field renamed because of name conflict.')
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if col_name != new_name and field_notes:
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field_params['db_column'] = col_name
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return new_name, field_params, field_notes
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def get_field_type(self, connection, table_name, row):
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"""
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Given the database connection, the table name, and the cursor row
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description, this routine will return the given field type name, as
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well as any additional keyword parameters and notes for the field.
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"""
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field_params = OrderedDict()
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field_notes = []
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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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field_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, field_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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field_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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field_params['max_length'] = int(row[3])
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if field_type == 'DecimalField':
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if row[4] is None or row[5] is None:
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field_notes.append(
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'max_digits and decimal_places have been guessed, as this '
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'database handles decimal fields as float')
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field_params['max_digits'] = row[4] if row[4] is not None else 10
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field_params['decimal_places'] = row[5] if row[5] is not None else 5
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else:
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field_params['max_digits'] = row[4]
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field_params['decimal_places'] = row[5]
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return field_type, field_params, field_notes
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def get_meta(self, table_name):
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"""
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Return a sequence comprising the lines of code necessary
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to construct the inner Meta class for the model corresponding
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to the given database table name.
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"""
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return ["",
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" class Meta:",
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" managed = False",
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" db_table = '%s'" % table_name]
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