20. A system to operate within a host organization, the system comprising: a processor to execute instructions stored in memory of the system; an analysis engine to generate indices from a dataset of columns and rows, the indices representing probabilistic relationships between the rows and the columns of the dataset; a predictive database to store the indices; a request interface to expose the predictive database; the request interface to receive 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 corresponding values by which to fix the column names; and a query interface to query the predictive 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, wherein querying the database using the PREDICT command term comprises passing a JavaScript Object Notation (JSON) structured query to the database, the JSON structured query having a query syntax of: the PREDICT command term as a required term; required specification of the one or more specified columns to be predicted; the required specification of the column names to be fixed and the values by which to fix the column names as the one or more column name=value pairs restricting output of the query to a predictive record set having returned elements that are probabilistically related to the one or more columns to be fixed and the corresponding values by which to fix the column names as specified via the one or more column name=value pairs; and an optional specification of one or more tables, datasets, data sources, and indices to be queried.
20. A system to operate within a host organization, the system comprising: a processor to execute instructions stored in memory of the system; an analysis engine to generate indices from a dataset of columns and rows, the indices representing probabilistic relationships between the rows and the columns of the dataset; a predictive database to store the indices; a request interface to expose the predictive database; the request interface to receive 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 corresponding values by which to fix the column names; and a query interface to query the predictive 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, wherein querying the database using the PREDICT command term comprises passing a JavaScript Object Notation (JSON) structured query to the database, the JSON structured query having a query syntax of: the PREDICT command term as a required term; required specification of the one or more specified columns to be predicted; the required specification of the column names to be fixed and the values by which to fix the column names as the one or more column name=value pairs restricting output of the query to a predictive record set having returned elements that are probabilistically related to the one or more columns to be fixed and the corresponding values by which to fix the column names as specified via the one or more column name=value pairs; and an optional specification of one or more tables, datasets, data sources, and indices to be queried. 24. The system of claim 20 , further comprising: a web-server to implement the request interface; wherein the web-server is to receive as input, a plurality of access requests from one or more client devices from among a plurality of customer organizations communicably interfaced with the host organization via a network; a multi-tenant database system with predictive database functionality to implement the predictive database; and wherein each customer organization is an entity selected from the group consisting of: a separate and distinct remote organization, an organizational group within the host organization, a business partner of the host organization, or a customer organization that subscribes to cloud computing services provided by the host organization.