There are certain changes that Snowflake does not support on existing columns. These include:
- Change the default for a column, unless the default is a sequence.
- Add a default for a column.
- Change a column data type to a different type
- Decrease the length of a text/string column
- Change the scale of a number column
Currently, Coalesce does not have a built in mechanism to work around Snowflake’s unsupported changes. Any unsupported changes must be completed off-platform directly in Snowflake. There are several methods for working around this described in this StackOverflow post, or you may select another method you devise. This will need to be completed anytime an unsupported change is required.