R50

R50 / 1c:Mc-1

Process Input Port reads zero or one Store

Store is read by zero, one or many Process Input Port

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Data from a Store can provide input to any number of Processes. In fact, only a Process may read directly from a Store. You can't, for example, connect an External Output directly to a Store.

In the Shlaer-Mellor application example, we use a Store to symbolize a populated model class. The data extracted from such as store cannot be definitively typed since many different model attribute subsets may be accessed. With an Aircraft Store, for example, you might read a set of ID, Altitude values or perhaps a single Heading value. Consequently, there is no modeled constraint on the data content read and written from a store.

The same Process may draw data from any number of Stores including none at all.

Formalization

Read Access.(Port, Process, Graph) -> Process Input Port.(Name, Process, Graph)
Read Access.(Store, Graph) -> Store.(Name, Graph)