“cannot be cast to type integer” error

Question

This is my first question so I will appreciate patience.

I changed a few attributes to IntegerField from CharField. Listed below is the code:

rating         


        

Answer 1

You need to add "USING (col_name::integer)" to eliminate this error. But in that case you have to use direct query.

migrateEngine.execute('ALTER TABLE test ALTER COLUMN testScore TYPE INTEGER USING testScore::integer')

Answer 2

if you are happy to throw away your data, you can delete the column and create a new one

if you want to keep your data, you need to either

a) give your new column a different name, or
b) create a temporary column to hold the data during the transition

you then need a sequence of migrations

1. a schema migration to add the new (or temp) column
2. a data migration that explicitly moves the data, doing any required conversion (e.g. "A" -> 1)
3. possibly a schema migration deleting your temporary column