Logical flow through the EXD query system and example of EXD query. (a) Logical flow through EXD query system. Boxes correspond to forms and web pages produced by the system. Arrows correspond to movements through the system available through hotlinks and buttons on the forms and pages. Number in circles indicated forms and web pages depicted in the example of an EXD query in b of this figure. (b) Illustration of an EXD query provided to give an impression of EXD system usage. (1) A user selects two data sets from the database, (2) selects an information field (SGDID) and nine Measures from these data sets, (3) specifies a query condition, and (4) obtains results. Forms and web pages shown in diagram are versions of actual EXD pages that have been reduced in size, abridged, and edited to highlight key features. Details pertaining to the example are given in the text.
