Security permissions in OLAP is similar to normal OLTP based environment. Say if you are using Pivot Table object in MS Office Excel to display the reports using OLAP objects like Cubes. To achieve this it should connect to an OLAP Server and database to fetch the data. As per the configuration when it tries to refresh data in the pivot table, it internally checks whether the windows user from the current system has required access rights. If the login that used in Excel do not have proper permission...(
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Read the complete post at http://sqlserver-qa.net/blogs/bi/archive/2007/09/25/olap-connectivity-from-pivot-table-in-excel-security-permissions.aspx