Commit 75303b01 authored by Tim Graham's avatar Tim Graham
Browse files

Fixed #24245 -- Added introspection for database defaults. 

Needed for tests for migrations handling of database defaults.
parent 64a899dc

django/db/backends/base/features.py

+3 −0
Original line number Diff line number Diff line
@@ -125,6 +125,9 @@ class BaseDatabaseFeatures(object): 
    # This is True for all core backends.

    can_introspect_null = True



    # Can the backend introspect the default value of a column?

    can_introspect_default = True



    # Confirm support for introspected foreign keys

    # Every database can do this reliably, except MySQL,

    # which can't do it for MyISAM tables

django/db/backends/mysql/introspection.py

+6 −5
Original line number Diff line number Diff line
@@ -9,8 +9,8 @@ from django.utils.encoding import force_text 


from MySQLdb.constants import FIELD_TYPE



FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('extra',))



FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('extra', 'default'))

InfoLine = namedtuple('InfoLine', 'col_name data_type max_len num_prec num_scale extra column_default')

foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
@@ -61,9 +61,9 @@ class DatabaseIntrospection(BaseDatabaseIntrospection): 
        #   not visible length (#5725)

        # - precision and scale (for decimal fields) (#5014)

        # - auto_increment is not available in cursor.description

        InfoLine = namedtuple('InfoLine', 'col_name data_type max_len num_prec num_scale extra')

        cursor.execute("""

            SELECT column_name, data_type, character_maximum_length, numeric_precision, numeric_scale, extra

            SELECT column_name, data_type, character_maximum_length, numeric_precision,

                   numeric_scale, extra, column_default

            FROM information_schema.columns

            WHERE table_name = %s AND table_schema = DATABASE()""", [table_name])

        field_info = {line[0]: InfoLine(*line) for line in cursor.fetchall()}
@@ -80,7 +80,8 @@ class DatabaseIntrospection(BaseDatabaseIntrospection): 
                               to_int(field_info[col_name].num_prec) or line[4],

                               to_int(field_info[col_name].num_scale) or line[5])

                            + (line[6],)

                            + (field_info[col_name].extra,)))

                            + (field_info[col_name].extra,)

                            + (field_info[col_name].column_default,)))

            )

        return fields

django/db/backends/oracle/features.py

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ class DatabaseFeatures(BaseDatabaseFeatures): 
    has_bulk_insert = True

    supports_tablespaces = True

    supports_sequence_reset = False

    can_introspect_default = False  # Pending implementation by an interested person.

    can_introspect_max_length = False

    can_introspect_time_field = False

    atomic_transactions = False

django/db/backends/sqlite3/introspection.py

+23 −9
Original line number Diff line number Diff line 
import re

from collections import namedtuple



from django.db.backends.base.introspection import (

    BaseDatabaseIntrospection, FieldInfo, TableInfo,
@@ -6,6 +7,7 @@ from django.db.backends.base.introspection import ( 




field_size_re = re.compile(r'^\s*(?:var)?char\s*\(\s*(\d+)\s*\)\s*$')

FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('default',))





def get_field_size(name):
@@ -69,8 +71,18 @@ class DatabaseIntrospection(BaseDatabaseIntrospection): 


    def get_table_description(self, cursor, table_name):

        "Returns a description of the table, with the DB-API cursor.description interface."

        return [FieldInfo(info['name'], info['type'], None, info['size'], None, None,

                 info['null_ok']) for info in self._table_info(cursor, table_name)]

        return [

            FieldInfo(

                info['name'],

                info['type'],

                None,

                info['size'],

                None,

                None,

                info['null_ok'],

                info['default'],

            ) for info in self._table_info(cursor, table_name)

        ]



    def column_name_converter(self, name):

        """
@@ -211,12 +223,14 @@ class DatabaseIntrospection(BaseDatabaseIntrospection): 


    def _table_info(self, cursor, name):

        cursor.execute('PRAGMA table_info(%s)' % self.connection.ops.quote_name(name))

        # cid, name, type, notnull, dflt_value, pk

        return [{'name': field[1],

        # cid, name, type, notnull, default_value, pk

        return [{

            'name': field[1],

            'type': field[2],

            'size': get_field_size(field[2]),

            'null_ok': not field[3],

                 'pk': field[5]     # undocumented

            'default': field[4],

            'pk': field[5],  # undocumented

        } for field in cursor.fetchall()]



    def get_constraints(self, cursor, table_name):

docs/releases/1.9.txt

+9 −0
Original line number Diff line number Diff line
@@ -165,6 +165,15 @@ Backwards incompatible changes in 1.9 
    deprecation timeline for a given feature, its removal may appear as a

    backwards incompatible change.



Database backend API

~~~~~~~~~~~~~~~~~~~~



* A couple of new tests rely on the ability of the backend to introspect column

  defaults (returning the result as ``Field.default``). You can set the

  ``can_introspect_default`` database feature to ``False`` if your backend

  doesn't implement this. You may want to review the implementation on the

  backends that Django includes for reference (:ticket:`24245`).



Miscellaneous

~~~~~~~~~~~~~