Added a mysql_old backend that matches the mysql backend prior to [4724]. This

is only for backwards compatibility purposes.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@4767 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/backends/mysql_old/introspection.py

@@ -0,0 +1,95 @@
+from django.db.backends.mysql.base import quote_name
+from MySQLdb import ProgrammingError, OperationalError
+from MySQLdb.constants import FIELD_TYPE
+import re
+
+foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
+
+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()]
+
+def get_table_description(cursor, table_name):
+    "Returns a description of the table, with the DB-API cursor.description interface."
+    cursor.execute("SELECT * FROM %s LIMIT 1" % quote_name(table_name))
+    return cursor.description
+
+def _name_to_index(cursor, table_name):
+    """
+    Returns a dictionary of {field_name: field_index} for the given table.
+    Indexes are 0-based.
+    """
+    return dict([(d[0], i) for i, d in enumerate(get_table_description(cursor, table_name))])
+
+def get_relations(cursor, table_name):
+    """
+    Returns a dictionary of {field_index: (field_index_other_table, other_table)}
+    representing all relationships to the given table. Indexes are 0-based.
+    """
+    my_field_dict = _name_to_index(cursor, table_name)
+    constraints = []
+    relations = {}
+    try:
+        # This should work for MySQL 5.0.
+        cursor.execute("""
+            SELECT column_name, referenced_table_name, referenced_column_name
+            FROM information_schema.key_column_usage
+            WHERE table_name = %s
+                AND table_schema = DATABASE()
+                AND referenced_table_name IS NOT NULL
+                AND referenced_column_name IS NOT NULL""", [table_name])
+        constraints.extend(cursor.fetchall())
+    except (ProgrammingError, OperationalError):
+        # Fall back to "SHOW CREATE TABLE", for previous MySQL versions.
+        # Go through all constraints and save the equal matches.
+        cursor.execute("SHOW CREATE TABLE %s" % quote_name(table_name))
+        for row in cursor.fetchall():
+            pos = 0
+            while True:
+                match = foreign_key_re.search(row[1], pos)
+                if match == None:
+                    break
+                pos = match.end()
+                constraints.append(match.groups())
+
+    for my_fieldname, other_table, other_field in constraints:
+        other_field_index = _name_to_index(cursor, other_table)[other_field]
+        my_field_index = my_field_dict[my_fieldname]
+        relations[my_field_index] = (other_field_index, other_table)
+
+    return relations
+
+def get_indexes(cursor, table_name):
+    """
+    Returns a dictionary of fieldname -> infodict for the given table,
+    where each infodict is in the format:
+        {'primary_key': boolean representing whether it's the primary key,
+         'unique': boolean representing whether it's a unique index}
+    """
+    cursor.execute("SHOW INDEX FROM %s" % quote_name(table_name))
+    indexes = {}
+    for row in cursor.fetchall():
+        indexes[row[4]] = {'primary_key': (row[2] == 'PRIMARY'), 'unique': not bool(row[1])}
+    return indexes
+
+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: 'IntegerField',
+    FIELD_TYPE.TINY_BLOB: 'TextField',
+    FIELD_TYPE.MEDIUM_BLOB: 'TextField',
+    FIELD_TYPE.LONG_BLOB: 'TextField',
+    FIELD_TYPE.VAR_STRING: 'CharField',
+}