I need to create a model for cities that contains only the fields id, city name, like a sql table but without creating a file that is not inheriting any Alfresco model (content, folder, etc). I can do that? or it is obligatory to inherit from the Alfresco models
I think that it is neccesary to inherit from one model from cm: or sys: (not completely sure). You can use more basic custom types of the Alfresco default content model. But, if they are based on cm:content or cm:folder, they are easier to check them in Alfresco Share for example, and besides, from CMIS point of view you can see them as an SQL table.