Allow a switch to be in more than one stack at a time, as in a switch

that is both in the experimental and control nets.

doc/setup-db.txt

@@ -211,7 +211,8 @@ max_vlan: Ditto, but the biggest number. Defaults to 1000.
 
 Finally, add switches to these stacks by putting entries in the switch_stacks
 table, listing the node_id of each switch and the stack_id of the stack it
-belongs to.
+belongs to. You can leave the 'is_primary' column of these rows with its default
+value (1).
 
 ##### Step 4 - Setup control hardware
 ##### Local Only

sql/database-create.sql

@@ -1517,7 +1517,8 @@ CREATE TABLE switch_stack_types (
 CREATE TABLE switch_stacks (
   node_id varchar(32) NOT NULL default '',
   stack_id varchar(32) NOT NULL default '',
-  PRIMARY KEY  (node_id)
+  is_primary tinyint(1) NOT NULL default '1',
+  KEY node_id (node_id)
 ) TYPE=MyISAM;
 
 --

sql/database-migrate.txt

@@ -2311,3 +2311,10 @@ last_net_act,last_cpu_act,last_ext_act);
 
 	cd <your_build_tree>/firewall
 	gmake insertrules
+
+1.300: Allow a switch to be in multiple stacks, and add a column that records
+       of the memberships is the primary one.
+
+        alter table switch_stacks drop primary key;
+	alter table switch_stacks add index (node_id);
+	alter table switch_stacks add column (is_primary tinyint(1) not null default '1');