1 files changed, 86 insertions, 0 deletions
diff --git a/webapp/django/db/backends/postgresql/introspection.py b/webapp/django/db/backends/postgresql/introspection.py
new file mode 100644
index 0000000000..7b3ab3bb8a
--- /dev/null
+++ b/webapp/django/db/backends/postgresql/introspection.py
@@ -0,0 +1,86 @@
+from django.db.backends import BaseDatabaseIntrospection
+
+class DatabaseIntrospection(BaseDatabaseIntrospection):
+    # Maps type codes to Django Field types.
+    data_types_reverse = {
+        16: 'BooleanField',
+        21: 'SmallIntegerField',
+        23: 'IntegerField',
+        25: 'TextField',
+        701: 'FloatField',
+        869: 'IPAddressField',
+        1043: 'CharField',
+        1082: 'DateField',
+        1083: 'TimeField',
+        1114: 'DateTimeField',
+        1184: 'DateTimeField',
+        1266: 'TimeField',
+        1700: 'DecimalField',
+    }
+        
+    def get_table_list(self, 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()]
+
+    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 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.
+        """
+        cursor.execute("""
+            SELECT con.conkey, con.confkey, c2.relname
+            FROM pg_constraint con, pg_class c1, pg_class c2
+            WHERE c1.oid = con.conrelid
+                AND c2.oid = con.confrelid
+                AND c1.relname = %s
+                AND con.contype = 'f'""", [table_name])
+        relations = {}
+        for row in cursor.fetchall():
+            try:
+                # row[0] and row[1] are like "{2}", so strip the curly braces.
+                relations[int(row[0][1:-1]) - 1] = (int(row[1][1:-1]) - 1, row[2])
+            except ValueError:
+                continue
+        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}
+        """
+        # This query retrieves each index on the given table, including the
+        # first associated field name
+        cursor.execute("""
+            SELECT attr.attname, idx.indkey, idx.indisunique, idx.indisprimary
+            FROM pg_catalog.pg_class c, pg_catalog.pg_class c2,
+                pg_catalog.pg_index idx, pg_catalog.pg_attribute attr
+            WHERE c.oid = idx.indrelid
+                AND idx.indexrelid = c2.oid
+                AND attr.attrelid = c.oid
+                AND attr.attnum = idx.indkey[0]
+                AND c.relname = %s""", [table_name])
+        indexes = {}
+        for row in cursor.fetchall():
+            # row[1] (idx.indkey) is stored in the DB as an array. It comes out as
+            # a string of space-separated integers. This designates the field
+            # indexes (1-based) of the fields that have indexes on the table.
+            # Here, we skip any indexes across multiple fields.
+            if ' ' in row[1]:
+                continue
+            indexes[row[0]] = {'primary_key': row[3], 'unique': row[2]}
+        return indexes
+