from __future__ import unicode_literals from collections import OrderedDict import keyword import re from optparse import make_option from django.core.management.base import NoArgsCommand, CommandError from django.db import connections, DEFAULT_DB_ALIAS class Command(NoArgsCommand): help = "Introspects the database tables in the given database and outputs a Django model module." option_list = NoArgsCommand.option_list + ( make_option('--database', action='store', dest='database', default=DEFAULT_DB_ALIAS, help='Nominates a database to ' 'introspect. Defaults to using the "default" database.'), ) requires_system_checks = False db_module = 'django.db' def handle_noargs(self, **options): try: for line in self.handle_inspection(options): self.stdout.write("%s\n" % line) except NotImplementedError: raise CommandError("Database inspection isn't supported for the currently selected database backend.") def handle_inspection(self, options): connection = connections[options.get('database')] # 'table_name_filter' is a stealth option table_name_filter = options.get('table_name_filter') table2model = lambda table_name: table_name.title().replace('_', '').replace(' ', '').replace('-', '') strip_prefix = lambda s: s[1:] if s.startswith("u'") else s with connection.cursor() as 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 "# * Remove `managed = False` lines if you wish to allow Django to create, modify, and delete the table" 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 [app_label]'" yield "# into your database." yield "from __future__ import unicode_literals" yield '' yield 'from %s import models' % self.db_module known_models = [] for table_name in connection.introspection.table_names(cursor): if table_name_filter is not None and callable(table_name_filter): if not table_name_filter(table_name): continue yield '' yield '' yield 'class %s(models.Model):' % table2model(table_name) known_models.append(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 = {} used_column_names = [] # Holds column names used in the table so far for i, row in enumerate(connection.introspection.get_table_description(cursor, table_name)): comment_notes = [] # Holds Field notes, to be displayed in a Python comment. extra_params = OrderedDict() # Holds Field parameters such as 'db_column'. column_name = row[0] is_relation = i in relations att_name, params, notes = self.normalize_col_name( column_name, used_column_names, is_relation) extra_params.update(params) comment_notes.extend(notes) used_column_names.append(att_name) # Add primary_key and unique, if necessary. 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 if is_relation: rel_to = "self" if relations[i][1] == table_name else table2model(relations[i][1]) if rel_to in known_models: field_type = 'ForeignKey(%s' % rel_to else: field_type = "ForeignKey('%s'" % rel_to else: # Calling `get_field_type` to get the field type string and any # additional parameters and notes. field_type, field_params, field_notes = self.get_field_type(connection, table_name, row) extra_params.update(field_params) comment_notes.extend(field_notes) 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 extra_params == {'primary_key': True}: if field_type == 'AutoField(': continue elif field_type == 'IntegerField(' and not connection.features.can_introspect_autofield: comment_notes.append('AutoField?') # Add 'null' and 'blank', if the 'null_ok' flag was present in the # table description. if row[6]: # If it's NULL... if field_type == 'BooleanField(': field_type = 'NullBooleanField(' else: extra_params['blank'] = True if field_type not in ('TextField(', 'CharField('): extra_params['null'] = True field_desc = '%s = %s%s' % ( att_name, # Custom fields will have a dotted path '' if '.' in field_type else 'models.', field_type, ) if extra_params: if not field_desc.endswith('('): field_desc += ', ' field_desc += ', '.join([ '%s=%s' % (k, strip_prefix(repr(v))) for k, v in extra_params.items()]) field_desc += ')' if comment_notes: field_desc += ' # ' + ' '.join(comment_notes) yield ' %s' % field_desc for meta_line in self.get_meta(table_name): yield meta_line def normalize_col_name(self, col_name, used_column_names, is_relation): """ Modify the column name to make it Python-compatible as a field name """ field_params = {} field_notes = [] new_name = col_name.lower() if new_name != col_name: field_notes.append('Field name made lowercase.') if is_relation: if new_name.endswith('_id'): new_name = new_name[:-3] else: field_params['db_column'] = col_name new_name, num_repl = re.subn(r'\W', '_', new_name) if num_repl > 0: field_notes.append('Field renamed to remove unsuitable characters.') if new_name.find('__') >= 0: while new_name.find('__') >= 0: new_name = new_name.replace('__', '_') if col_name.lower().find('__') >= 0: # Only add the comment if the double underscore was in the original name field_notes.append("Field renamed because it contained more than one '_' in a row.") if new_name.startswith('_'): new_name = 'field%s' % new_name field_notes.append("Field renamed because it started with '_'.") if new_name.endswith('_'): new_name = '%sfield' % new_name field_notes.append("Field renamed because it ended with '_'.") if keyword.iskeyword(new_name): new_name += '_field' field_notes.append('Field renamed because it was a Python reserved word.') if new_name[0].isdigit(): new_name = 'number_%s' % new_name field_notes.append("Field renamed because it wasn't a valid Python identifier.") if new_name in used_column_names: num = 0 while '%s_%d' % (new_name, num) in used_column_names: num += 1 new_name = '%s_%d' % (new_name, num) field_notes.append('Field renamed because of name conflict.') if col_name != new_name and field_notes: field_params['db_column'] = col_name return new_name, field_params, field_notes def get_field_type(self, connection, table_name, row): """ Given the database connection, the table name, and the cursor row description, this routine will return the given field type name, as well as any additional keyword parameters and notes for the field. """ field_params = OrderedDict() field_notes = [] try: field_type = connection.introspection.get_field_type(row[1], row) except KeyError: field_type = 'TextField' field_notes.append('This field type is a guess.') # This is a hook for data_types_reverse to return a tuple of # (field_type, field_params_dict). if type(field_type) is tuple: field_type, new_params = field_type field_params.update(new_params) # Add max_length for all CharFields. if field_type == 'CharField' and row[3]: field_params['max_length'] = int(row[3]) if field_type == 'DecimalField': if row[4] is None or row[5] is None: field_notes.append( 'max_digits and decimal_places have been guessed, as this ' 'database handles decimal fields as float') field_params['max_digits'] = row[4] if row[4] is not None else 10 field_params['decimal_places'] = row[5] if row[5] is not None else 5 else: field_params['max_digits'] = row[4] field_params['decimal_places'] = row[5] return field_type, field_params, field_notes def get_meta(self, table_name): """ Return a sequence comprising the lines of code necessary to construct the inner Meta class for the model corresponding to the given database table name. """ return ["", " class Meta:", " managed = False", " db_table = '%s'" % table_name]