Review of the article: An informal introduction to Constraint Database System

This paper gave new database model with merits over object-oriented and relational one. Key idea of constraints is to view both data as constraints and vice versa. This paper discussed how geographic data, spatial data and cad cam data are integrated with Generalized tuples. This paper gave idea on how constraint solver handles different operators involved in the query for efficient query evaluation. Thus constraint data base have potential to overcome the impedance mis-match not just hiding it. Active use of constraints is called as constraint propagation. Constraints are accumulated through query evaluation, both during progression down the index tree and when data is retrieved. Very important uses of constraints in data base are 1) integrity constraints, which must be satisfied in every database state. 2) Capturing partial information of the object. This paper is not much concern about Partial information of object. Major advantages of using Constraint logic Programming are it provides means to express complex problems in simple way. It also supports for rapid prototyping. It typically allows users to control the search for solution. These programs can be integrated with standard mathematical programs. This logic programming systems find solutions one-at-a-time. And finally constraint propagation is suitable tool for finding feasible solutions effectively. In GIS application, routing is the typical GIS problem in planning and operating in a mines, escape routes must be planned for each point, here escape routes are naturally satisfy safety constraints. This is one of the major application of constraints in the field of GIS, considering multidimensional indexing techniques as constraints, it is easy to optimise, better, to constraint the search of relevant data. This paper described various applications of constraints logic programming in Utility Companies, Marketing companies, Warehousing and transportation.