11. A computer-program product tangibly embodied in a non-transitory machine-readable storage medium, the computer-program product including instructions operable to cause a computing device to perform computer operations including: receive computer-executable query instructions to solve a mixed-integer linear programming (MILP) problem, wherein the query instructions comprise: a first expression conveying an objective function and at least one side constraint of the MILP problem, wherein the objective function and the at least one side constraint define a master problem of the MILP problem; a second expression conveying a first mapping of data values of graph data associated with the MILP problem to a first graph; and a third expression conveying a selection of a first graph-based algorithm to solve a first subproblem of the MILP problem based on the first graph; replace the third expression in the query instructions with a fourth expression as part of a decomposition of the MILP problem, the fourth expression comprising instructions to implement the first graph-based algorithm to solve the first subproblem; and operations of an iteration to solve the MILP problem, wherein the operations of the iteration comprise: executing the first expression to derive a solution to the master problem; and executing the fourth expression to derive a solution to the first subproblem based on the first mapping and the solution to the master problem.
11. A computer-program product tangibly embodied in a non-transitory machine-readable storage medium, the computer-program product including instructions operable to cause a computing device to perform computer operations including: receive computer-executable query instructions to solve a mixed-integer linear programming (MILP) problem, wherein the query instructions comprise: a first expression conveying an objective function and at least one side constraint of the MILP problem, wherein the objective function and the at least one side constraint define a master problem of the MILP problem; a second expression conveying a first mapping of data values of graph data associated with the MILP problem to a first graph; and a third expression conveying a selection of a first graph-based algorithm to solve a first subproblem of the MILP problem based on the first graph; replace the third expression in the query instructions with a fourth expression as part of a decomposition of the MILP problem, the fourth expression comprising instructions to implement the first graph-based algorithm to solve the first subproblem; and operations of an iteration to solve the MILP problem, wherein the operations of the iteration comprise: executing the first expression to derive a solution to the master problem; and executing the fourth expression to derive a solution to the first subproblem based on the first mapping and the solution to the master problem. 17. The computer-program product of claim 11 , the computing device caused to perform operations including, receive the graph data, wherein: the data values of the graph data are associated with nodes of the first graph; and the second expression comprises instructions to iterate through the nodes of the first graph.