A frequent requirement in database classes is for students to
implement a prototype database application where several design
documents are required. One such document is an access matrix,
such as the one shown in Figure 3 which displays the possible
operations that an input form performs on a table. This type of
matrix serves two purposes. First, it provides an overview of the
system as well as identifies implementation difficulties. The
example, Figure 3 clearly shows that the ORDER form is by far the
most difficult because it accesses five different tables, while the
other forms only access one table. A second advantage is that the
matrix visually depicts rules of integrity. For instance, if any change
such as change in a data type, were made in any of the tables, all
forms affected by this change can easily be identified by parsing the
table’s column in the matrix. Although this type of matrix appears
simple, students have tremendous difficulty creating it. The matrix
animation allows a user to select an operation inside the matrix and
then a simulation of the form/program performing the operation on
the table will be displayed. For example, if a user clicks on ‘U’ of
the customers form on the customers table, a simulation of an
update of customer data will be presented.
A frequent requirement in database classes is for students toimplement a prototype database application where several designdocuments are required. One such document is an access matrix,such as the one shown in Figure 3 which displays the possibleoperations that an input form performs on a table. This type ofmatrix serves two purposes. First, it provides an overview of thesystem as well as identifies implementation difficulties. Theexample, Figure 3 clearly shows that the ORDER form is by far themost difficult because it accesses five different tables, while theother forms only access one table. A second advantage is that thematrix visually depicts rules of integrity. For instance, if any changesuch as change in a data type, were made in any of the tables, allforms affected by this change can easily be identified by parsing thetable’s column in the matrix. Although this type of matrix appearssimple, students have tremendous difficulty creating it. The matrixanimation allows a user to select an operation inside the matrix andthen a simulation of the form/program performing the operation onthe table will be displayed. For example, if a user clicks on ‘U’ ofthe customers form on the customers table, a simulation of anupdate of customer data will be presented.
การแปล กรุณารอสักครู่..