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  • nahla Al-gethami thinks this is interesting:

The first item in the upper left corner of Figure 5-1 is the “Customer” external entity, which is a rectangle that represents individual customers who are buying things at the supermarket. This symbol has three arrows pointing away from it to rounded rectangular symbols. These arrows represent data flows and show that the external entity (Customer) provides three “bundles” of data to processes that use the data.


Cover of Systems Analysis and Design, 4th Edition