1. A method in a host organization, the method comprising: generating indices from a dataset of columns and rows, the indices representing probabilistic relationships between the rows and the columns of the dataset; storing the indices within a database of the host organization; exposing the database of the host organization via a request interface; receiving, at the request interface, a query for the database specifying at least (i) a PREDICT command term, (ii) one or more specified columns to be predicted, and (iii) one or more column name=value pairs specifying column names to be fixed and the values by which to fix them; and querying the database using the PREDICT command term and passing the one or more specified columns to be predicted and the one or more column name=value pairs to generate a representation of a joint conditional distribution of the one or more specified columns to be predicted fixed according to the column name=value pairs using the indices stored in the database.