Analyzing Systems Using Data Dictionaries

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]

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]

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]

Each data element should be defined once in the data dictionary and may also be entered previously on an element description form, such as the one illustrated in the figure below. Characteristics commonly included on the element description form are the following: Element ID. This optional entry allows the analyst to build automated data dictionary… [Continue Reading]

All base elements must be stored in the system. Derived elements, such as the employee year-to-date gross pay, may also be stored in the system. Data stores are created for each different data entity being stored. That is, when data flow base elements are grouped together to form a structural record, a data store is… [Continue Reading]

Data dictionary entries may be created after the data flow diagram has been completed, or they may be constructed as the data flow diagram is being developed. The use of algebraic notation and structural records allows the analyst to develop the data dictionary and the data flow diagrams using a top-down approach. For instance, the… [Continue Reading]

The ideal data dictionary is automated, interactive, online, and evolutionary. As the systems analyst learns about the organization’s systems, data items are added to the data dictionary. On the other hand, the data dictionary is not an end in itself and must never become so. To avoid becoming sidetracked with the building of a complete… [Continue Reading]

Extensible markup language (XML) is a language that can be used to exchange data between businesses or between systems within a business. It is similar to HTML, the markup language used to create Web pages, but is more powerful. HTML is concerned primarily with formatting a document; XML addresses the problem of sharing data when… [Continue Reading]

Often the element structure of XML content is defined using a document type definition (DTD). A DTD is used to determine whether the XML document content is valid, that is, whether it conforms to the order and type of data that must be present in the document. The DTD is easy to create and well… [Continue Reading]