After successive levels of data flow diagrams are complete, systems analysts use them to help catalog the data processes, flows, stores, structures, and elements in a data dictionary. Of particular importance are the names used to characterize data items. When given an opportunity to name components of data-oriented systems, the systems analyst needs to work… [Continue Reading]
Analyzing Systems Using Data Dictionaries
The Data Dictionary
The data dictionary is a specialized application of the kinds of dictionaries used as references in everyday life. The data dictionary is a reference work of data about data (that is, metadata), one that is compiled by systems analysts to guide them through analysis and design. As a document, the data dictionary collects and coordinates… [Continue Reading]
The Data Repository
Although the data dictionary contains information about data and procedures, a larger collection of project information is called a repository. The repository concept is one of the many impacts of CASE tools and may contain the following: Information about the data maintained by the system, including data flows, data stores, record structures, elements, entities, and… [Continue Reading]
Defining the Data Flows & Describing Data Structures
Data flows are usually the first components to be defined. System inputs and outputs are determined from interviewing, observing users, and analyzing documents and other existing systems. The information captured for each data flow may be summarized using a form containing the following information: ID, an optional identification number. Sometimes the ID is coded using… [Continue Reading]
Logical and Physical Data Structures
When data structures are first defined, only the data elements that the user would see, such as a name, address, and balance due, are included. This stage is the logical design, showing what data the business needs for its day-to-day operations. As we learned from HCI, it is important that the logical design accurately reflect… [Continue Reading]
