Wiki page says “A semantic layer is a business representation of corporate data that helps end users access data autonomously using common business terms”. BI Semantic Model in MSBI is a layer between Data warehouse and reporting tools/Users. BI Semantic Model maps the data structure/schema of data warehouse or any data source in more business oriented terms with all the possible relations defined and business logic implemented which can be easily understood by both the business users and the IT Professional. In general, we do not provide direct data warehouse (Raw data) access to the data consumers. Data Consumer will be accessing the BI Semantic Model , BI Semantic Model will be in turn connecting to the data warehouse or data source and in that way it gives a layer of abstraction. BI Semantic Model can address all the BI requirement be it Reporting, analytical, scorecard & dashboard , Personal/Self Service BI and custom application. In larger organizations each department may have their own BI Semantic layer as “Single source of truth” so that the users can consistently consume the correct data.
BI Semantic Model in SQL Server has three major elements. Data Model, Business logic and Data Access. There are three different approach to create BI Semantic Model in SQL Server. PowerPivot Workbook, Tabular Model and Multidimensional Model