MDX-How can I setup default dimension member in cube calculation script?

Q: How can I setup default dimension member in Calculation script?

A: You can use ALTER CUBE statement. Syntax:

ALTER CUBE CurrentCube | YourCubeName UPDATE DIMENSION <dimension name>, DEFAULT_MEMBER='<default member>';

Example:
At first lets test what is default value

SELECT [Geography].[Geography].DefaultMember ON 0 FROM [Adventure Works]

Result:

All Geographies
$80,450,596.98

Now lets apply default member to be Canada:

ALTER CUBE [Adventure Works] UPDATE DIMENSION [Geography].[Geography]
, DEFAULT_MEMBER = [Geography].[Geography].[Country].&[Canada];

Run query to test results:

SELECT [Geography].[Geography].DefaultMember ON 0
FROM [Adventure Works]

Results:

Canada
$14,377,925.60