Changes between Version 13 and Version 14 of TracDev/DatabaseApi

Timestamp:

Sep 15, 2010, 7:47:11 PM (14 years ago)

Author:

Christian Boos

Comment:

start to talk about the db_query

TracDev/DatabaseApi

@@ -53 +53 @@
 See more details in the [../ApiChanges/0.12#with_transaction] paragraph.
 
+The use of `env.get_db_cnx()` is still possible, but deprecated.
+An alternative `env.get_read_db()` method can be used to get a "read" only access to the database (for performing `SELECT` queries).
+
 === Trac 0.13 API
 
@@ -70 +73 @@
 
 It does essentially the same thing as the 0.12 version above in a terser way.
+
+The use of `env.get_db_cnx()` is now strongly discouraged.
+
+For performing read-only accesses, a second context manager is provided:
+
+{{{
+#!python
+from trac.env import Environment
+def myFunc():
+    env = Environment('/path/to/projenv')
+    with env.db_query as db:
+        cursor = db.cursor()
+        # Execute some SQL "SELECT" statements
+
+    return
+}}}
+
+This one enforces the notion of read-access, because the `db` connection bound to the context doesn't support the `commit()` or `rollback()` methods. As there's not `commit()` upon exit, one could question the usefulness of this construct. The main interest is in better locality of the  connection: in order to improve concurrency and (... finish later)
+
 
 === Configuration