1. A method, implemented by a computing device, for validating application models within a database environment, the method comprising: receiving an application schema, wherein the application schema defines constraints for validating application models that are associated with the application schema; storing the application schema within the database environment; receiving an application model, wherein the application model defines operation of an application, and wherein the application model is associated with the application schema; validating the application model, wherein the validating comprises performing validation of the application model against the application schema; upon successful validation of the application model, storing the application model within the database environment, wherein validation is successful when the application model satisfies all constraints of the application schema, wherein a constraint is satisfied when the constraint is consistent with the application model; and when the validation of the application model is unsuccessful, outputting a result of the validation that indicates the application model will not be stored within the database environment, wherein validation is unsuccessful when the application model fails at least one constraint of the application schema; wherein the application schema remains available within the database environment, and cannot be removed from the database environment, while there are any application models stored within the database environment that are associated with the application schema and that were validated against the application schema, wherein the application schema remains available for review and evaluation within the database environment.