What is the difference between a “schema”, a “schema language”, and a “data model”?
The database schema is like a blueprint that describes the layout of the data contained in the database: what kinds of fields are present and how they are organized. For example, it could state that one kind of experiment will be called a binding_assay, and will contain a field for the contributor’s name which will be a string of characters, some other field which is a number, etc. The schema is stored in a file that is read by the database software, so minor changes like, say, adding a new field are relatively easy from a programming perspective because they can be made in this file without changing the programs at all. (Though of course, all the existing data would need to be changed to conform to the new schema file, which could be a rather tedious job.) The language for specifying the schema is just a set of grammatical rules for describing schemas in general. That is, what exactly should the schema file say in order to tell the database software that there will be a table called b
