Comment 5 for bug 511979

This is just a limitation on Postgres engine, that you can't alter column if it is involved in any view. Obviously this can be dealt by creating "discount" column with required type in the first place...

This is what needs to be done to bypass this error:

1. get the view definition schema
2. Drop the view
3. alter "dicount" column
4. recreate view
5. Comment the alter statement in sale.py
6. restart erp server
7. install magentoconnect

I did the pl/pgsql script for this - see attachment, but it will only run as is on postgres 9. But it can be adopted to run on 8 as well or you need to do it manually in psql.