Column.is_integer() method

[clrcrl]

The Column class has an instance method, is_numeric() that returns true if the column is a fixed-precision Numeric type (eg. numeric), else False (including integer and float types).

There are instances where I want to determine:

• Is this column generally numeric? I.e. one of: decimal, float, integer
• Is this column an integer? i.e. one of bigint, smallint, integer (e.g. on Redshift).

The second one is easy: let's add an is_integer() method.
But I don't know how to name the first method, since is_numeric() is already reserved for numeric (i.e. decimal) columns. Can we rename is_numeric to is_decimal, or will that mess up too many things?

[drewbanin]

I don't think renaming is_numeric() is a good idea. Can we instead name this new method is_number()? numeric is a well-defined type on pg/redshift/snowflake/bigquery/etc. We'll probably also want to add a method for is_float().

The is_number() implementation could just check if a column is_integer() or is_numeric() or is_float().

[drewbanin]

@clrcrl are you interested in contributing a PR for this issue? It might be a little tricky with differing semantics between each of the databases that dbt supports, but the code will be pretty straightforward to implement after some fact-finding work :)

[clrcrl]

Yeah I could do that for sure!

[clrcrl]

Happy for @beckjake to take this one!

[beckjake]

Fixed in #2046