Django

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Changeset 2691

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Timestamp:
04/12/06 20:52:12 (3 years ago)
Author:
adrian
Message:

magic-removal: Fixed #1483 -- Added MySQL foreign-key inspection to 'inspectdb'. Thanks, mir@noris.de

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  • django/branches/magic-removal/AUTHORS

    r2641 r2691  
    8181    Jason McBrayer <http://www.carcosa.net/jason/> 
    8282    michael.mcewan@gmail.com 
     83    mir@noris.de 
    8384    mmarshall 
    8485    Eric Moritz <http://eric.themoritzfamily.com/> 

  • django/branches/magic-removal/django/db/backends/mysql/introspection.py

    r2465 r2691  
    11from django.db import transaction 
    22from django.db.backends.mysql.base import quote_name 
     3from MySQLdb import ProgrammingError, OperationalError 
    34from MySQLdb.constants import FIELD_TYPE 
     5import re 
     6 
     7foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)") 
    48 
    59def get_table_list(cursor): 
    …… 
    1317    return cursor.description 
    1418 
     19def _name_to_index(cursor, table_name): 
     20    """ 
     21    Returns a dictionary of {field_name: field_index} for the given table. 
     22    Indexes are 0-based. 
     23    """ 
     24    return dict([(d[0], i) for i, d in enumerate(get_table_description(cursor, table_name))]) 
     25 
    1526def get_relations(cursor, table_name): 
    16     raise NotImplementedError 
     27    """ 
     28    Returns a dictionary of {field_index: (field_index_other_table, other_table)} 
     29    representing all relationships to the given table. Indexes are 0-based. 
     30    """ 
     31    my_field_dict = _name_to_index(cursor, table_name) 
     32    constraints = [] 
     33    relations = {} 
     34    try: 
     35        # This should work for MySQL 5.0. 
     36        cursor.execute(""" 
     37            SELECT column_name, referenced_table_name, referenced_column_name 
     38            FROM information_schema.key_column_usage 
     39            WHERE table_name = %s 
     40                AND referenced_table_name IS NOT NULL 
     41                AND referenced_column_name IS NOT NULL""", [table_name]) 
     42        constraints.extend(cursor.fetchall()) 
     43    except (ProgrammingError, OperationalError): 
     44        # Fall back to "SHOW CREATE TABLE", for previous MySQL versions. 
     45        # Go through all constraints and save the equal matches. 
     46        cursor.execute("SHOW CREATE TABLE %s" % table_name) 
     47        for row in cursor.fetchall(): 
     48            pos = 0 
     49            while True: 
     50                match = foreign_key_re.search(row[1], pos) 
     51                if match == None: 
     52                    break 
     53                pos = match.end() 
     54                constraints.append(match.groups()) 
     55 
     56    for my_fieldname, other_table, other_field in constraints: 
     57        other_field_index = _name_to_index(cursor, other_table)[other_field] 
     58        my_field_index = my_field_dict[my_fieldname] 
     59        relations[my_field_index] = (other_field_index, other_table) 
     60 
     61    return relations 
    1762 
    1863def get_indexes(cursor, table_name):