Is there a way to limit data to numerics in VARCHAR datatype? We want users to o

You could strip out all non-numeric characters as the user types.

Here is a SAIL recipe that provides a nice example: forum.appian.com/.../SAIL_Recipes.html

You have a number of options - most use validations and various tests - but one of the simplest is just to cast the value parameter of the text field to integer or decimal depending on your requirements:

load(
local!someValue,
a!textField(
label: "Value",
value: tointeger(local!someValue),
saveInto: local!someValue
)
)

Thanks for the suggestions! I'll test both out and see which one works best for us.

I think changing the user input without even giving him a hint of what exactly happened will not be good practice. The user won't possibly understand why the values entered by him has changed.

You must use a validation message so as to prompt him to enter only numeric values. You can create a rule for that.

Thanks - I agree. We're going to display instructions as well.