1. An object-oriented temporal context programming system comprising: data objects, each data object defining a class of object with at least one attribute, said attribute being stored in the database with an indication of the effective time of the attribute, any change in attribute also being stored in the data object along with an indication of the time of effect of the change in the attribute; and methods which the class can carry out, said methods having an argument which is effective time, said method being stored in the database with an indication of the effective time of the method, any change in said method also being stored in the data object along with an indication of the time of effect of the change in the method, execution of said method with a particular time argument utilizing the attributes of the effected data objects and the particular method in effect for the particular time specified.