1. A computer-implemented method of executing machine instructions, the method comprising: storing into a column of a first table of a relational database, software expressed in an intermediate level language (ILL); interpreting the ILL software in a virtual machine in a relational database management system used to access the relational database; operating a compiler in the relational database management system, to receive the ILL software as input and to emit native code comprising said machine instructions; storing the native code emitted by the compiler in a second table of the relational database, wherein the second table is distinct from the first table; storing in the relational database an indicator of a plurality of properties required to execute the native code; checking if said indicator stored in the relational database matches a new indicator of said plurality of properties; executing said machine instructions in the native code emitted by the compiler, via the virtual machine in the relational database management system, if a result of said checking is true; and marking the native code as invalid if said result of said checking is false.