TARGIT InMemory Database, offered for use with TARGIT Decision Suite, is similar to Microsoft's tabular engine. Both are column-store databases.
Column-store databases allow for large data set storage in a small space when loaded InMemory. Rather than repeating all the data values for each row like a traditional relational database would do, a column-store database only keeps a distinct list of values for each field and replaces the values of the transactions with highly indexed integer values so it can quickly look up the values and present the data set. This allows a 50GB+ database to fit into a few GB of memory space.
However, unlike Microsoft's tabular engine, the TARGIT InMemory Database can be used with standard edition of SQL Server and most other databases. Data can even be loaded directly from the source systems into the TARGIT InMemory Database using the TARGIT InMemory ETL Studio. This means there is no longer a reliance on SQL Server.