Programming DAO: Overview - Access Database Design and Programming - page 197

delete it before running this program. Also, you may need to switch away from and then
return to the Query tab to refresh the list.)
14.2 The DAO Object Model
As the name Data Access Objects suggests, the DAO is, at least in part, an object-
oriented environment. In particular, the DAO is implemented as a hierarchy of collections
of objects. Figure 14-5 shows the DAO Object Model, describing the collections and
their objects.
Figure 14-5. The DAO object model
Each of the shaded boxes represents a collection of objects. (Thus DBEngine is the only
noncollection.) The name of the objects contained within a given collection is just the
singular of the collection name. For instance, the TableDefs collection holds TableDef
objects, and the Documents collection holds Document objects. DBEngine is the only
standalone object—not contained in any collection.
There is a potential point of confusion about the DAO object hierarchy in Figure 14-5
that we should address. Consider, for example, the relationship between the Databases
and Workspaces collections. It would be incorrect to say, as one might infer from the
diagram, that the Databases collection is contained in the Workspaces collection. Indeed,
the line from Workspaces to Databases means that each Workspace object has (or as
Microsoft would say, “contains”) a Databases collection.