It would be nice to have Mergeant use certain commands for its own, such 
as, CONNECT and DISCONNECT.  This can come in handy for scripts.

Format for CONNECT:

  CONNECT libgdaDSN connection_string_values;

  libgdaDSN is a DSN setup for libgda

connection_string_values allows to set any missing connection parameters 
or override any connection parameters in the libgda DSN mentioned in 
libgdaDSN

Example of CONNECT:

   CONNECT SomeLibgdaDsn user=danmorg;password=fun2db;

Mergeant tries to connect to the data source via libgda, if connected 
successfully, displays a message, such as:

   Connected successfully for libgdaDSN as 1.

If connect another, it would display:

   Connected successfully for libgdaDSN as 2.

After connecting via the second connection, it would automatically 
default to using that second connection.

If you want to use the first connection again:

   USE 1;

Mergeant could list the open connections somewhere.

If you want to disconnect from the second connection, then use DISCONNECT:

   DISCONNECT 2;

You can disconnect from all connections by using ALL:

   DISCONNECT ALL;

I'm sure there are other nice commands that Mergeant could use.