The paper attempts theoretically to clarify the interrelation between various levels of descriptions used in the modelling and the programming of information systems. We suggest an analysis where we characterise the description levels with respect to how precisely they may handle information about given types of properties, and examine how descriptions on higher levels translate into descriptions on lower levels. Our example looks at temporal properties where the information is concerned with the existence in time. In a high level temporal model with information kept in a three-dimensional space the existences in time can be mapped precisely and consistently securing a consistent handling of the temporal properties. We translate the high level temporal model into an entity-relationship model, with the information in a two-dimensional graph, and finally we look at the translations into relational and other textual models. We also consider the aptness of models that include procedural mechanisms such as active and object databases.