Description

Title: “Project Three: Two-Tier Client-Server Application Development With MySQL and JDBC” Points: 100 points

Objectives: To develop a two-tier Java based client-server application interacting with a MySQL database utilizing JDBC for the connectivity. This project is designed to give you some experience using the various features of JDBC and its interaction with a MySQL DB Server environment.

Description: In this assignment you will develop a Java-based GUI front-end (client-side) application that will connect to your MySQL server via JDBC.

You are to develop a Java application that will allow any client (the end-user) to execute commands against the database. You will create a Java GUI-based application front-end that will accept any MySQL DDL or DML command, pass this through a JDBC connection to the MySQL database server, execute the statement and return the results to the client. Note that while technically your application must be able to handle any DDL or DML command, we won’t actually use all of the commands available in these sublanguages. For one thing, it would be quite rare to allow a client to create a database or a table within a database. Note too, that the only DML command that uses the executeQuery() method of JDBC is the Select command, all other DML and DDL commands utilize executeUpdate(). Some screen shots of what your Java GUI front-end should look like are shown below. Basically, this GUI is an extension of the GUI that was developed in the lecture notes and is available on WebCourses as DisplayQueryResults.java. Your Java application must give the user the ability to execute any SQL DDL or DML command for which the user has the correct permissions. User information for connections will be maintained in properties files, but the user must supply their username and password (for their MySQL server account) via the GUI. You will be able to start multiple instances of your Java application and allow different clients to connect simultaneously to the MySQL DB sever, since the default number of connections is set at 151 (See your Workbench options file under the networking tab). In addition to the client interactions with your application, a background (business logic) transaction logging operation will occur which keeps a running total of the number of queries and the number of updates that have occurred via the user application. This is a separate database (i.e., a completely different database than any to which a client user can connect), that the application will connect to using root user privileges in a separate properties file. This separate properties file is not accessible by any end user. Each user operation will cause the application to make this connection and update the operational logging database table. More details on this aspect of the application are shown below and will be covered in the Q&A sessions.

Once you’ve created your application, you will execute a sequence of DML and DDL commands and illustrate the output from each in your GUI for two different users. For this project you will create, in addition to the root user, a client user with limited permissions on the database (see below). The root user is assumed to have all permissions on the database, any command they issue will be executed. The client user will be far more restricted.

References for this assignment:
Notes: Lecture Notes for MySQL and JDBC.

Input Specification:
The first step in this assignment is to login to the MySQL Workbench as the root user and execute/run the script to create and populate the backend database. This script is available on the assignment page and is named “project3dbscript.sql”. This script creates a database named project3. You can use the MySQL Workbench for this step, or the command line whichever you prefer. This script file is available on WebCourses.

The second step is to create authorizations for a client user (in addition to the root user) named client. By default your root user has all permissions on the project3 database. Use either SQL Grant statements from the command line or the MySQL Workbench (see separate document for details on how to accomplish this task) to check and set permissions for the client as follows:

The third step is to create the operationslog database using the project3operationslog.sql script. This script file is also available on WebCourses.

Output Specification:
There are three parts for the output for this project. Part 1 is to provide screen shots from your application which clearly show the complete query/command expression and results for each of the commands that appear in the script named: project3rootuserscript.sql available on the course website. There are eight different commands in this script and some of the commands will have more than one output capture (see below). Part 2 is to provide screen shots from your application which clearly show the complete query/command expression and results for each of the commands that appear in the script named: project3clientuserscript.sql available on the course website. There are three different commands in this script and some of the commands will have more than one output capture (see below). To produce your final output, first recreate the database, then run the root user commands followed by the client commands in script order within each script file.

Deliverables:
1. All of the .java files associated with your application.
2. All 14 screenshots from the execution of the commands specified in the project3rootuserscript.sql script.
3. All 8 screenshots from the execution of the commands specified in the project3clientuserscript.sql script.
4. A screenshot showing the final state of the operationscount table after executing the command select * from operationscount; once both the root user and client user command script files have been completely executed.

Details:
Shown on the next page is a screen shot of the initial GUI. Notice that there is a single drop-down list for selecting the properties file that will be used to make the client connection. The user credentials along with the JDBC driver and database URL will be specified in these files. The client must enter only their user credentials (username and password) through the GUI. Your application must verify that the user-entered credentials match those in the specified properties file before making a connection to the database. If the user entered credentials do not match those in the specified properties file, a message will be displayed to the user and no connection to the database will be established.

You should provide buttons for the user to clear the command window as well as the result window. The status of the connection should be returned to the GUI and displayed in the connection area.

The output of all SQL commands should be returned to the SQL Execution Result window. Please note that only single SQL commands can be executed via this application (will not execute scripts of commands). We will also not go to the effort of making the application display the results of MySQLspecific commands. (When a MySQL-specific command is executed, the SQL Execution Result window does not need to display any results, if you wanted to you could display the line “MySQL command executed” in the results window, but this is not required.)

As each user command is executed (only successful commands – some of the client command will not be successful) the operationscount table in the operationslog database must be updated by your application. Each query and each update will be logged (counted) separately. Your application must obtain a connection to the operationslog database and perform the update with root user credentials.
Only successful operations will be logged – any transaction erroring will not increment any counter. These operations are invisible to the end user (regardless of who the user is, including root users). The application must connect to the operationslog database using a properties file which contains all necessary connection information.

Note that for non-query DML and DDL commands, before and after screen shots must be taken to illustrate the basic effect of the command. See pages 8-9 for an illustration of this.

The remainder of the document illustrates the application at various phases during execution.

Screen shot illustrating an initial connection.

Illustrating the drop-down list of possible propertied files that could be selected.

User has connected to a database and issued a select command. Results are displayed in the SQL Execution window.

A more complicated query:

When the user makes a mistake entering a SQL command:

The following three screen shots illustrate that your application should be able to handle non-query commands from the users.

Before screen shot of a subset of the riders relation:

Insert command issued:

After screen shot of subset of riders relation after insert command was issued:

Screen shot illustrating the client user issuing a select command.

Screen shot illustrating the client user issuing a command for which they do not have permission:

The following screenshot illustrates the operationscount table values after various operations have been completed. This screenshot is taken from a root user account in the MySQL Workbench using the operationslog database. Note that the numbers shown in this screenshot are not the correct numbers that you will see after executing the root user command script followed by the client user command script. This is just an example.