Unformatted text preview: processes must have an input. P7: don't show external entities' processes External Entity: E1: it must be out of scope (EXTERNAL). E2: must be NOUN. No problem with having the same entity to avoid crossing lines. Data Stores DS1: singular countable nouns o can have adjective before DS2: The data store may represent a person, place, a filing cabinet, a computerized file or database. Temporary scratch paper or a temporary computer file is not included on DFD. DS3: give each data store a unique identifying number like D1, D2 …. DS4: Data stores must have I/O both; otherwise there is a p...
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- Fall '12