Document SQLTransaction a little better

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/sqlclient/trunk@19776 72102866-910b-0410-8b05-ffd578937521

SQLClient.h

@@ -853,7 +853,10 @@ extern NSString	*SQLUniqueException;
  * then use the -execute method to perform all the statements as a
  * single operation.<br />
  * Any exception is caught and re-raised in the -execute method after any
- * tidying up to leave the database in a consistent state.
+ * tidying up to leave the database in a consistent state.<br />
+ * NB. This class is not in itsself thread-safe, though the underlying
+ * database operations should be.   If you have multiple threads, you
+ * should create multiple SQLTransaction instances, at least one per thread.
  */
 @interface	SQLTransaction : NSObject
 {
@@ -875,6 +878,12 @@ extern NSString	*SQLUniqueException;
  */
 - (void) add: (NSString*)stmt with: (NSDictionary*)values;
 
+/**
+ * Returns the database client with which this instance operates.<br />
+ * This client is retained by the transaction.
+ */
+- (SQLClient*) db;
+
 /**
  * Performs any statements added to the transaction as a single operation.
  * If any problem occurs, an NSException is raised, but the database connection

SQLClient.m

@@ -1562,6 +1562,11 @@ static unsigned int	maxConnections = 8;
   [self _addInfo: [_db _substitute: stmt with: values]];
 }
 
+- (SQLClient*) db
+{
+  return _db;
+}
+
 - (void) execute
 {
   if (_count > 0)