13. The computer system of claim 12 , wherein the validator is one or more of: an expression that defines a range of valid data, a set of valid data, or a code module that, when executed against particular input data, determines whether the particular input data matches a specified syntax or data model.
12. The computer system of claim 9 , wherein the instructions, when executed by the one or more processors, further cause: storing a validator for the first property type, wherein the validator defines valid data for the first property type; determining whether the first data matches the validator before storing the first data in the first property instance.