1 files changed, 98 insertions, 0 deletions
diff --git a/webapp/django/db/backends/mysql/introspection.py b/webapp/django/db/backends/mysql/introspection.py
new file mode 100644
index 0000000000..d8d59b73a1
--- /dev/null
+++ b/webapp/django/db/backends/mysql/introspection.py
@@ -0,0 +1,98 @@
+from django.db.backends import BaseDatabaseIntrospection
+from MySQLdb import ProgrammingError, OperationalError
+from MySQLdb.constants import FIELD_TYPE
+import re
+
+foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
+
+class DatabaseIntrospection(BaseDatabaseIntrospection):
+    data_types_reverse = {
+        FIELD_TYPE.BLOB: 'TextField',
+        FIELD_TYPE.CHAR: 'CharField',
+        FIELD_TYPE.DECIMAL: 'DecimalField',
+        FIELD_TYPE.NEWDECIMAL: 'DecimalField',
+        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: 'CharField',
+        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',
+    }
+
+    def get_table_list(self, 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(self, cursor, table_name):
+        "Returns a description of the table, with the DB-API cursor.description interface."
+        cursor.execute("SELECT * FROM %s LIMIT 1" % self.connection.ops.quote_name(table_name))
+        return cursor.description
+
+    def _name_to_index(self, 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(self.get_table_description(cursor, table_name))])
+
+    def get_relations(self, 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 = self._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" % self.connection.ops.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 = self._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(self, 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" % self.connection.ops.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
+