Added first stab at 'django-admin.py inspectdb', which takes a database name and introspects the tables, outputting a Django model. Works in PostgreSQL and MySQL. It's missing some niceties at the moment, such as detection of primary-keys and relationships, but it works. Refs #90.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@384 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/bin/django-admin.py

@@ -7,6 +7,7 @@ ACTION_MAPPING = {
     'adminindex': management.get_admin_index,
     'createsuperuser': management.createsuperuser,
 #     'dbcheck': management.database_check,
+    'inspectdb': management.inspectdb,
     'runserver': management.runserver,
     'sql': management.get_sql_create,
     'sqlall': management.get_sql_all,
@@ -66,6 +67,17 @@ def main():
         print_error("Your action, %r, was invalid." % action, sys.argv[0])
     if action in ('createsuperuser', 'init'):
         ACTION_MAPPING[action]()
+    elif action == 'inspectdb':
+        try:
+            param = args[1]
+        except IndexError:
+            parser.print_usage_and_exit()
+        try:
+            for line in ACTION_MAPPING[action](param):
+                print line
+        except NotImplementedError:
+            sys.stderr.write("Error: %r isn't supported for the currently selected database backend." % action)
+            sys.exit(1)
     elif action in ('startapp', 'startproject'):
         try:
             name = args[1]

django/core/db/__init__.py

@@ -37,5 +37,7 @@ dictfetchall = dbmod.dictfetchall
 get_last_insert_id = dbmod.get_last_insert_id
 get_date_extract_sql = dbmod.get_date_extract_sql
 get_date_trunc_sql = dbmod.get_date_trunc_sql
+get_table_list = dbmod.get_table_list
 OPERATOR_MAPPING = dbmod.OPERATOR_MAPPING
 DATA_TYPES = dbmod.DATA_TYPES
+DATA_TYPES_REVERSE = dbmod.DATA_TYPES_REVERSE

django/core/db/backends/mysql.py

@@ -68,6 +68,11 @@ def get_date_trunc_sql(lookup_type, field_name):
         subtractions.append(" - interval (DATE_FORMAT(%s, '%%%%m')-1) month" % field_name)
     return "(%s - %s)" % (field_name, ''.join(subtractions))
 
+def get_table_list(cursor):
+    "Returns a list of table names in the current database."
+    cursor.execute("SHOW TABLES")
+    return [row[0] for row in cursor.fetchall()]
+
 OPERATOR_MAPPING = {
     'exact': '=',
     'iexact': 'LIKE',
@@ -115,3 +120,23 @@ DATA_TYPES = {
     'USStateField':      'varchar(2)',
     'XMLField':          'text',
 }
+
+DATA_TYPES_REVERSE = {
+    FIELD_TYPE.BLOB: 'TextField',
+    FIELD_TYPE.CHAR: 'CharField',
+    FIELD_TYPE.DECIMAL: 'FloatField',
+    FIELD_TYPE.DATE: 'DateField',
+    FIELD_TYPE.DATETIME: 'DateTimeField',
+    FIELD_TYPE.DOUBLE: 'FloatField',
+    FIELD_TYPE.FLOAT: 'FloatField',
+    FIELD_TYPE.INT24: 'IntegerField',
+    FIELD_TYPE.LONG: 'IntegerField',
+    FIELD_TYPE.LONGLONG: 'IntegerField',
+    FIELD_TYPE.SHORT: 'IntegerField',
+    FIELD_TYPE.STRING: 'TextField',
+    FIELD_TYPE.TIMESTAMP: 'DateTimeField',
+    FIELD_TYPE.TINY_BLOB: 'TextField',
+    FIELD_TYPE.MEDIUM_BLOB: 'TextField',
+    FIELD_TYPE.LONG_BLOB: 'TextField',
+    FIELD_TYPE.VAR_STRING: 'CharField',
+}

django/core/db/backends/postgresql.py

@@ -71,6 +71,17 @@ def get_date_trunc_sql(lookup_type, field_name):
     # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
     return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
 
+def get_table_list(cursor):
+    "Returns a list of table names in the current database."
+    cursor.execute("""
+        SELECT c.relname
+        FROM pg_catalog.pg_class c
+        LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
+        WHERE c.relkind IN ('r', 'v', '')
+            AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
+            AND pg_catalog.pg_table_is_visible(c.oid)""")
+    return [row[0] for row in cursor.fetchall()]
+
 # Register these custom typecasts, because Django expects dates/times to be
 # in Python's native (standard-library) datetime/time format, whereas psycopg
 # use mx.DateTime by default.
@@ -129,3 +140,19 @@ DATA_TYPES = {
     'USStateField':      'varchar(2)',
     'XMLField':          'text',
 }
+
+# Maps type codes to Django Field types.
+DATA_TYPES_REVERSE = {
+    16: 'BooleanField',
+    21: 'SmallIntegerField',
+    23: 'IntegerField',
+    25: 'TextField',
+    869: 'IPAddressField',
+    1043: 'CharField',
+    1082: 'DateField',
+    1083: 'TimeField',
+    1114: 'DateTimeField',
+    1184: 'DateTimeField',
+    1266: 'TimeField',
+    1700: 'FloatField',
+}

django/core/db/backends/sqlite3.py

@@ -109,6 +109,9 @@ def _sqlite_date_trunc(lookup_type, dt):
     elif lookup_type == 'day':
         return "%i-%02i-%02i 00:00:00" % (dt.year, dt.month, dt.day)
 
+def get_table_list(cursor):
+    raise NotImplementedError
+
 # Operators and fields ########################################################
 
 OPERATOR_MAPPING = {
@@ -157,3 +160,5 @@ DATA_TYPES = {
     'USStateField':                 'varchar(2)',
     'XMLField':                     'text',
 }
+
+DATA_TYPES_REVERSE = {}

django/core/management.py

@@ -430,6 +430,32 @@ def createsuperuser():
     print "User created successfully."
 createsuperuser.args = ''
 
+def inspectdb(db_name):
+    "Generator that introspects the tables in the given database name and returns a Django model, one line at a time."
+    from django.core import db
+    from django.conf import settings
+    settings.DATABASE_NAME = db_name
+    cursor = db.db.cursor()
+    yield 'from django.core import meta'
+    yield ''
+    for table_name in db.get_table_list(cursor):
+        object_name = table_name.title().replace('_', '')
+        object_name = object_name.endswith('s') and object_name[:-1] or object_name
+        yield 'class %s(meta.Model):' % object_name
+        yield '    db_table = %r' % table_name
+        yield '    fields = ('
+        cursor.execute("SELECT * FROM %s LIMIT 1" % table_name)
+        for row in cursor.description:
+            field_type = db.DATA_TYPES_REVERSE[row[1]]
+            field_desc = 'meta.%s(%r' % (field_type, row[0])
+            if field_type == 'CharField':
+                field_desc += ', maxlength=%s' % (row[3])
+            yield '        %s),' % field_desc
+        yield '    )'
+        yield ''
+inspectdb.help_doc = "Introspects the database tables in the given database and outputs a Django model module."
+inspectdb.args = "[dbname]"
+
 def runserver(port):
     "Starts a lightweight Web server for development."
     from django.core.servers.basehttp import run, WSGIServerException