How it works
Please note that this tool only reads database schema.
It does not modify anything, so you are always safe running it against any database.
Step 1 - generating model file
Run the tool against the 'ideal' database and extract schema to model file.
dbschemaupdater /connection:"Persist Security Info=False;Integrated Security=SSPI;database=my_cool_db_name;server=(local)" /generate+ /model:modelfile.xml
Result of this operation is modelfile.xml which contains information about target schema.
Step 2 - generating update script
Run the tool against database you want to update, and provide model file as an argument.
dbschemaupdater /connection:"Persist Security Info=False;Integrated Security=SSPI;database=the_old_db_name;server=(local)" /model:modelfile.xml /output:update.sql
Result of this stage is an SQL-script that you can later edit and/or manually apply to the database you want to update.
Step 3 - update database
Open SQL Management Studio, connect to the database and run the script. If everything went well you'll get updated database.