1. A computer-implemented method for a computing environment employing a matrix-based mathematical programming language, the method comprising: generating a heterogeneous dataset in the computing environment, wherein the heterogeneous dataset embodies a plurality of variables for a plurality of subjects, wherein each element of a respective variable has a same data type, wherein the variables comprise at least two data types; accessing contents of the heterogeneous dataset with a single command in the computing environment, wherein the single command is based on at least one of: a command to access contents of the heterogeneous dataset for one of the variables and for one of the subjects, a command to access contents of the heterogeneous dataset for all subjects associated with one of the variables, or a command to access contents of the heterogeneous dataset for a portion of the plurality of the variables and for a portion of the plurality of the subjects; and providing in the computing environment a portion of the heterogeneous dataset based on the single command.