Instructions for using the relational algebra expression evaluator

1. Make sure that you have Java installed on your computer. If not, you can download the Java JDK (Java Development Kit) from here. 
2. Download and extract the contents of this zip file. You should now have a university folder that contains a relational algebra expression evaluator written in Java and text files corresponding to the 11 relations referenced in the university database in chapter 2. 
3. Open the university folder and execute the relational algebra expression evaluator named raevalPlus.jar by double-clicking the jar file, or by right clicking and opening it with the Java runtime
• Note: If that does not launch the interpreter, double click the cmd.bat file contained in the folder. This will open a terminal window. Run the relational algebra evaluator using the command: java   -jar    raevalPlus.jar
4. In the relational algebra expression evaluator window prompt >, type in:
• source "loadAll.txt" and press Control-Enter. This reads the data in the text files to create relations corresponding to the 11 relations in the university database: department, instructor, student, advisor, classroom, course, prereq, section, takes, teaches, time_slot
  
• Explore relational algebra by evaluating relational algebra expressions. For example:
  
1. select instructor where salary > 65000 and press Control-Enter
2. select instructor times (teaches rename (id as i_id)) where id=i_id and press Control-Enter
3. project (select instructor times (teaches rename (id as i_id)) where id=i_id) over name, course_id, semester, year and press Control-Enter