Description
To incorporate many of the techniques you’ve learned so far this semester into a distributed three-tier web-based application which uses servlets and JSP technology running on a Tomcat container/server to access and maintain a persistent MySQL database using JDBC.
suppliers (snum, sname, status, city) //information about suppliers parts (pnum, pname, color, weight, city) //information about parts jobs (jnum, jname, numworkers, city) //information about jobs
shipments (snum, pnum, jnum, quantity) //suppliers ship parts to jobs in specific quantities
The first-tier (client-level front-end) of your application will be a JSP page that allows the client to enter SQL commands into a window (i.e. a form) and submit them to the server application for processing. The front-end (and only the front-end) will utilize JSP technology. The client front-end will provide the user a simple form in which they will enter a SQL command (any DML, DDL, or DCL command could theoretically be entered by the user, however we will restrict to queries, insert, update, replace, and delete commands). The front-end will provide only two buttons for the user, an Execute button that will cause the execution of the SQL command they enter, and a Reset button that simply clears any content in the form input area. The client front-end will run on any web-based browser that you would like to use. You can elect to have a default query or not, it is entirely your decision. The application will connect to the backend database as a root user client.
The second-tier servlet, in addition to handling the SQL command interface will also implement the business/application logic. This logic will increment by 5, the status of a supplier anytime that supplier is involved in the insertion/update of a shipment record in which the quantity is greater than or equal to 100. Note that any update of quantity >= 100 will affect any supplier involved in a shipment with a quantity >= 100. The example screen shots illustrate this case. An insert of a shipment tuple (S5, P6, J7, 400) will cause the status of every supplier who has a shipment with a quantity of 100 or greater to be increased by 5. In other words, even if a supplier’s shipment is not directly affected by the update, their status will be affected if they have any shipment with quantity >= 100. (See page 9 for a bonus problem that implements a modified version of this business rule.) The business logic of the second tier will reside in the servlet on the Tomcat web-application server (server-side application). This means that the business logic is not to be implemented in the DBMS via a trigger.
The third-tier (back-end) is the persistent MySQL database described above and is under control of the MySQL DBMS server. All you need to do with the database is run the creation/population script.
References:
Notes: Lecture Notes for MySQL installation and use. Documentation for MySQL available at: http://www.mysql.com. More information on JDBC can be found at: http://www.oracle.com/technetwork/java/javase/jdbc/index.html . More information on Tomcat can be found at http://tomcat.apache.org. Lecture Notes for Servlets. Lecture Notes for JSPs.
