[Student Record Prototype System]

by

TABLE OF CONTENTS

CHAPTER 3: FORM TYPE3

Database Schema4

The Language Tutor8

Consolidation10

REFERENCES16

CHAPTER 3: FORM TYPE

A number of free GIS packages are listed in a document entitled “Open Source GIS”, last updated in 2008. However, many of the packages listed here are not fully fledged GIS software packages with an appropriate installer (executable file) for the Windows platform. Indeed, a number of them are code libraries for use by developers. In contrast, the website of the Open Source Geospatial Foundation lists three desktop GIS - GRASS, Quantum GIS and gvSIG- in this case, these are packages that have passed through an incubation process before joining the Foundation. Previous reviews of FOSS GIS include Steiniger and Bocher (2009), Donnelly (2010) and Chen et al. (2010), with the latter being particularly relevant as the authors ranked packages using criteria which included Internet connection and security, operating system, programming language, level of complexity, data format and database connectivity, maturity, and installation processes.

Steiniger and Bocher (2009) provide additional information on the database connectivity of the packages appearing at the top of the Chen et al. (2010) rankings, and Donnelly (2010) reviews an almost identical list of software from the perspective of basic functionality such as opening an Esri shapefile, selecting features and producing a map layout.The form type is the central concept of our approach and IIS Case. A form type generalizes document types, i.e. screen forms that users utilize to communicate with an information system. IIS Case imposes strict structuring rules on form types. Using this tool, a designer specifies screen forms of transaction programs and, indirectly, creates an initial set of attributes and constraints.

During the automated process of the design, which demands a minimal interaction with the designer, the form types are transformed into an implementation DB schema. A form type is a named tree structure, whose nodes are called component types. Each component type is identified by its name within the scope of a form type, and has non-empty sets of attributes and keys, and a possibly empty set of unique constraints. A set of allowed database operations must be associated with each component type.

The set of allowed operations is a subset of the set of 'standard' operations {retrieve, insert, update, delete}. If the update operation is associated with a component type, the set of updatable attributes of the component type must be also specified. In addition, each attribute of a component type may be mandatory or optional. If a component type attribute must not have null values, it is designated as mandatory. Otherwise, it is optional. Each attribute of a component type is selected from a global set of all information system attributes. The attributes are globally identified only by their names.

In the past, spatial data was produced and provided by either governmental bodies, such as national mapping agencies, commercial data providers or other large organizations. It was provided in a top down manner as data products, such as those provided by the Ordnance Survey (the National Mapping Agency in ...