There are 2 permanent ways to define connection string :

1) XML Config file (recommended)

2) SQL server table.

whenever; deploying the package on production change the connection file accordingly.

Also you can use one...

select a sql script tool, create the sql connection and write a sql script to check if  row count> 0 then go for update command by selecting the update db task...

Perhaps you can set the input column properties to varchar/nvarchar by right clicking on the tool.

Anil