period starting in 1996. Multidimensional Storage modes Microsoft Analysis Services takes a neutral position in the MOLAP vs. ROLAP arguments among OLAP products. It allows all the flavors of MOLAP, ROLAP and HOLAP to be used within the same model. Partition storage modes MOLAP - Multidimensional OLAP - Both fact data and aggregations are processed, stored, and indexed using a special format optimized for multidimensional data. ROLAP - Relational OLAP - Both fact data and aggregations remain in the relational data source, eliminating the need for special processing. HOLAP - Hybrid OLAP - This mode uses the relational data source to store the fact data, but pre-processes aggregations and indexes, storing these in a special format, optimized for multidimensional data. Dimension storage modes MOLAP - dimension attributes and hierarchies are processed and stored in the special format ROLAP - dimension attributes are not processed and remain in the relational data source. Tabular storage mode In-Memory - Tabular storage mode compresses data and stores the model in memory for faster execution of queries. APIs and object models Microsoft Analysis Services supports different sets of APIs and object models for different operations and in different programming environments. Querying XML for Analysis - The lowest level API. It can be used from any platform and in any language that supports HTTP and XML OLE DB for OLAP - Extension of OLEDB. COM based and suitable for C/C++ programs on Windows platform. ADOMD - Extension of ADO. COM Automation based and suitable for VB programs on Windows platform. ADOMD.NET - Extension of ADO.NET. .NET based and suitable for managed code programs on CLR platforms. ADO.NET Entity Framework - Entity Framework and LINQ can be used on top of ADOMD.NET (SSAS Entity Framework Provider is required) Administration and management DSO - For AS 2000. COM Automation based and suitable for VB programs on Windows platform. AMO - For AS 2005 and later versions. .NET based and suitable for managed code programs on CLR platforms. Query languages Microsoft Analysis Services supports the following query languages Data definition language (DDL) DDL in Analysis Services is XML based and supports commands such as <Create>, <Alter>, <Delete>, and <Process>. For data mining models import and export, it also supports PMML. Data manipulation language (DML) MDX - for querying OLAP cubes LINQ - for querying OLAP cubes from .NET using ADO.NET Entity Framework and Language INtegrated Query (SSAS Entity Framework