Available-to-promise on an in-memory column store

A system and method of determining an earliest delivery date for a demand on the basis of a fact table stored in a database, where the demand indicates both a desired date and a desired quantity for items from a stock, where a fact time series is comprised by and/or deducible from the fact table, and where the fact time series comprises fact tuples indicating both a fact date and a change in quantity of stock items that occurred on this fact date. The method includes generating an aggregated time series from the fact time series by defining and/or obtaining discrete time intervals, and generating, for at least one discrete time interval, an aggregated tuple indicating both its corresponding discrete time interval and the aggregated change in quantity of stock items that occurred in its corresponding discrete time interval.