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Documentation Techniques

Five documentation techniques include data flow diagrams, entity relationship diagrams, system flowcharts, program flowcharts, and record layout diagrams.

Data Flow Diagrams and Entity Relationship Diagrams

* Data flow diagrams – Data flow diagrams (DFD) use symbols to represent the entities, processes, data flows, and data stores that pertain to a system. * Entities – Entities in a DFD are objects that lie at the boundary of the system being modeled. They are the sources of and destinations for data and can be other interfacing systems or entities external to the organization. Entities are labeled as singular nouns on a DFD. Data stores represent the accounting files and records used in each process, and the labeled arrows represent data flows between processes, data stores, and entities. * Processes – Processes are labeled with a descriptive verb. Process objects should not be represented as nouns. The arrows connecting objects should be labeled to represent specific flows of data. Also, each data flow label should be unique. The same label should not be attached to two different flow lines in the same DFD. * Usage – Systems analysts use DFDs extensively to represent the logical elements of the system. It does not depict the physical system. * Entity relationship diagrams – An entity relationship diagram is used to represent the relationship between business entities. An entity is anything about the organization that captures data. The labeled connecting line represents the nature of the relationship between two entities. Cardinality is the degree of the relationship and the numeric mapping between entities. Cardinality reflects normal business rules as well as organizational policy. Systems designers identify organization entities and prepare a model for them. The data model is the blueprint for what ultimately become the physical database. * Relationship between ER diagrams and data flow diagrams – A DFD is a model of system processes and the ER diagram models the data used in the system. Each data store in the DFD represents a corresponding entity in the ER diagram.

System Flowcharts

A system flowchart is the graphical representation of the physical relationships among key elements of a system, including organizational departments, manual activities, computer programs, hard-copy accounting records, and digital records. They also describe the physical computer media being employed in the system. * Flowcharting manual activities – The flowchart should be labeled to clearly identify the system that it represents, the correct symbols should be used to represent the various entities in the system, all symbols should be labeled, lines should have arrowheads to clearly show the process flow direction and sequence of events, and a text description should be included if necessary. * Lay out the physical areas of activity – A flowchart reflects the physical system, which is represented as vertical columns of events and actions separated by lines of demarcation.

Program Flowcharts

System flowcharts do not provide all the operational details that are sometimes needed, which are provided by a program flowchart. Every program represented in a system flowchart should have a supporting program flowchart that describes its logic. A separate symbol represents each step of the program’s logic, and each symbol represents one or more lines of computer code. Accountants sometimes use program flowcharts to verify the correctness of program logic. 1. The program retrieves a single record from the unedited transaction file and stores it in memory. 2. The first logical tests is to see if the program has reached the end-of-file (EOF) condition for the transaction file. Most file structures use a special record or marker to indicate an EOF condition. When EOF is reached, the edit program will terminate and the next program in the system will be executed. 3. Processing involves a series of tests to identify certain clerical and logical errors. Each test is represented by a decision symbol and evaluates the presence or absence of a condition. 4. Error-free records are sent to the edited transaction file. 5. Records containing errors are sent to the error file. 6. The program loops back to step 1 and the process is repeated until the EOF condition is reached.

Record Layout Diagrams

Record layout diagrams are used to reveal the internal structure of digital records in a flat-file or database table. The layout diagram usually shows the name, data type, and length of each attribute or field in the record. Each data attribute and key field is shown in terms of its name and relative location in the record.