You could include a little of relational thinking by going back to Venn diagrams - expressing entity types [Manx cat, Siamese Cat, Moggy, Siberian Tiger, Lion, Panther] and entity supertypes [Domestic Cats, Big Cats] that way, and get the kids to thing about individual things as instances of types of things, differntiated by attributes. You can bring in a little Platonism by talking about ideal types and how everything has attributes that we can all see, and get them to understand attributes by thinking about what makes 1 type of thing different from another.
Entity and Referential integrity is also easily explained. Every instance of stuff you record information about [the things that you're interested in], must be uniquely identifiable. Every unique ID of stuff you're interested in must have a corresponding foriegn key value.
E.g. Every pet has an owner. An owner may have more than 1 pet, but a pet may not have more than one owner.
When you begin to build rules around data, you then get away from flat file databases and start identifying and building relationships between entities. This thinking is at the root of data modelling and database design.
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Date: 2007-05-18 03:21 pm (UTC)Entity and Referential integrity is also easily explained. Every instance of stuff you record information about [the things that you're interested in], must be uniquely identifiable. Every unique ID of stuff you're interested in must have a corresponding foriegn key value.
E.g. Every pet has an owner. An owner may have more than 1 pet, but
a pet may not have more than one owner.
When you begin to build rules around data, you then get away from
flat file databases and start identifying and building
relationships between entities. This thinking is at the root of
data modelling and database design.