IT 304 Midterm Part 2 PDF

IT 304 – Quantitative Research LEVEL 0 DFD Data Flow Diagrams (DFDs) a Level 0 DFD gives an overview of how the system works These diagrams crop up in a few different places often in reports...

IT 304 – Quantitative Research LEVEL 0 DFD Data Flow Diagrams (DFDs) a Level 0 DFD gives an overview of how the system works These diagrams crop up in a few different places often in reports and planning stages of E.g for a back up system various systems. Example: Show how data is used and most importantly how it moves around a system any computer system has data being stored and it will move around various different components Common symbols: An IT technician uses File Manager. We have our original files/data and copy of files stored on another storage device. LEVEL 1 DFD Go into more detail than a Level 0 what is using the data or what is it doing to the data DFD LEVEL 1 RULES what/who is providing or receiving the data Each external entity has at least one input or output Each process has at least one input or output where data is being held (e.g. a database or just a file) Data flows in only one direction the transfer of data (we shouldn't have these sort of double arrows in a level one DFD) Every data flow is labelled Every data flow connects to at least on process