place docs for DBAPI-agnostic transaction_isolation setting for sqlite, pg [ticket:1784]

3 files changed, 17 insertions, 4 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 7de5cafad..aa2048d4b 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -36,6 +36,14 @@ PostgreSQL 8.2 supports an ``INSERT...RETURNING`` syntax which SQLAlchemy suppor
 as well.  A future release of SQLA will use this feature by default in lieu of 
 sequence pre-execution in order to retrieve new primary key values, when available.
 
+Transaction Isolation Level
+---------------------------
+
+:func:`create_engine` accepts an ``isolation_level`` parameter which results in 
+the command ``SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL <level>``
+being invoked for every new connection.   Valid values for this parameter are 
+``READ_COMMITTED``,  ``READ_UNCOMMITTED``, ``REPEATABLE_READ``, and ``SERIALIZABLE``.
+
 INSERT/UPDATE...RETURNING
 -------------------------
 
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index 2a51a7239..6ae6c6c08 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -25,9 +25,6 @@ psycopg2-specific keyword arguments which are accepted by :func:`~sqlalchemy.cre
   at a time are fetched over the wire to reduce conversational overhead.
 * *use_native_unicode* - Enable the usage of Psycopg2 "native unicode" mode per connection.  True  
   by default.
-* *isolation_level* - Sets the transaction isolation level for each transaction
-  within the engine. Valid isolation levels are `READ_COMMITTED`,
-  `READ_UNCOMMITTED`, `REPEATABLE_READ`, and `SERIALIZABLE`.
 
 Transactions
 ------------
diff --git a/lib/sqlalchemy/dialects/sqlite/base.py b/lib/sqlalchemy/dialects/sqlite/base.py
index ca0a39136..ec3d7b8ac 100644
--- a/lib/sqlalchemy/dialects/sqlite/base.py
+++ b/lib/sqlalchemy/dialects/sqlite/base.py
@@ -41,7 +41,15 @@ to the Table construct::
     Table('sometable', metadata,
             Column('id', Integer, primary_key=True), 
             sqlite_autoincrement=True)
-    
+
+Transaction Isolation Level
+---------------------------
+
+:func:`create_engine` accepts an ``isolation_level`` parameter which results in 
+the command ``PRAGMA read_uncommitted <level>`` being invoked for every new 
+connection.   Valid values for this parameter are ``SERIALIZABLE`` and 
+``READ UNCOMMITTED`` corresponding to a value of 0 and 1, respectively.
+
 """
 
 import datetime, re, time