From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Tue, 4 Mar 2008 19:31:33 +0000 (+0000)
Subject: - postgres PGArray is a "mutable" type by default;
X-Git-Tag: rel_0_4_4~38
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=390c3e4d5ce57a9768de848ff0c1a0c483a4e081;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- postgres PGArray is a "mutable" type by default;
when used with the ORM, mutable-style equality/
copy-on-write techniques are used to test for changes.
---

diff --git a/CHANGES b/CHANGES
index 93dfd62b29..ff99249b9b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -99,6 +99,10 @@ CHANGES
 
     - postgres TIMESTAMP renders correctly [ticket:981]
 
+    - postgres PGArray is a "mutable" type by default;
+      when used with the ORM, mutable-style equality/
+      copy-on-write techniques are used to test for changes.
+      
 0.4.3
 ------
 - sql
diff --git a/lib/sqlalchemy/databases/postgres.py b/lib/sqlalchemy/databases/postgres.py
index 9f8e986071..19228f558e 100644
--- a/lib/sqlalchemy/databases/postgres.py
+++ b/lib/sqlalchemy/databases/postgres.py
@@ -113,11 +113,24 @@ class PGBoolean(sqltypes.Boolean):
     def get_col_spec(self):
         return "BOOLEAN"
 
-class PGArray(sqltypes.Concatenable, sqltypes.TypeEngine):
-    def __init__(self, item_type):
+class PGArray(sqltypes.MutableType, sqltypes.Concatenable, sqltypes.TypeEngine):
+    def __init__(self, item_type, mutable=True):
         if isinstance(item_type, type):
             item_type = item_type()
         self.item_type = item_type
+        self.mutable = mutable
+
+    def copy_value(self, value):
+        if self.mutable:
+            return list(value)
+        else:
+            return value
+
+    def compare_values(self, x, y):
+        return x == y
+
+    def is_mutable(self):
+        return self.mutable
 
     def dialect_impl(self, dialect, **kwargs):
         impl = self.__class__.__new__(self.__class__)