Data Type in DSV

I have Varchar column called "Age", which capture patient age. and I am trying to use grouping property of the Age dimension, since it is varchar type, the grouping is messed up, such as 20 - 4, 40 - 5. So I say, ok, I need to cast to int, so I change my age dimension to int, but the fact table need to be changed too, so I did cast(age as int) as Age, however I got error:

maxlength applies to string data type only, you cannot set column 'Age' property MaxLength to be non-negative number.

Any advice?

Dear Friend,

First when U Chages any data type in Fact Table. First remove all references in Cube. Suppose U want to change Age Datatype then first remove Age Measures from Cube or if any other reference is there like dimension using this field remove that from cube, then save, then process again. Now U can change that age datatype. Do fresh DataSourceView. Then add the things U removed. And Re-process your cube now this error will not come.