Assignment 4

This assignment is due Tuesday, April 28 before class time. Do this assignment on turing.cs.niu.edu or hopper.cs.niu.edu. It is worth 100 points. No late homework.

Submission:

To receive credit for this assignment you must turn in a hardcopy of your script AND a machine-readable version using the following rules.

Hardcopy: (Same rules as before.) Assignments must be stapled. Written homework must be turned in at the beginning of the class period to be considered on time. Print programs using non-proportional type (e.g., Courier) in at least 10 point size. You may use proportional type for answers to questions, but make sure the type size is at least as large as what you are reading (i.e., 12 point). This means that you may not print 2-up. Homework should be turned in on 8 1/2 x 11 paper and must be stapled together. The upper right corner of the first page should contain (a) your name, (b) CS330, (c) the assignment number, (d) the date. If you cannot attend class, written assignments will be considered on time if they are left under my office door provided they are received before class time.

Machine-readable: (a) Name your script hw4-xxxx, where xxxx = the first four letters of your last name. (If your last name has fewer than four letters, just use your last name.) (b) Email your script as an attachment to your TA at z139048. Note: no machine name, just the z-number. Email from turing/hopper cannot go outside the cluster; this form will send email within the cluster, regardless of which machine your account is located on. (c) Your script must be mailed as an attachment, not included in the body of the email. (d) The subject line should also say hw4-xxxx.

One email program you can use is alpine. (This is the one used by Linus Torvalds, the originator of linux.) Start it with the alpine command. The first time you will get a message about being counted as an alpine user. After that, use 'c' to compose your email, then fill in the "to" address (z139048), the name of your attachment, and the subject. Then say "hi" to your TA in the body of the email, just so it won't be blank. Finally, use 'x' to send your message, confirming with 'y' when asked.

Maintain automobile records in a database

The first parameter is always the database being queried. The second parameter is always the command that will be executed. Any parameters that follow are specific to the command that was issued.

The general syntax of script invocation is:

autodb dbname command param1 ... paramN

where:

• dbname is the name of the file that contains the database records
• command is one of: create, add, view or delete
• param1 ... paramN are paramemters to the specified command

Description of commands and parameters

• create title text
  creates a new database with name dbname. Any text following the create command will become the first line in the database file. If no text is given, the default is "Automobile Database".
  An error occurs if the database already exists.
  Upon success, the create command reports "New database created".
  


• add make model year color
  adds a new record to the database. Up to 4 parameters can be listed in this order: make, model, year, color. If only 3 parameters are given then the script will prompt for the fourth; if only 2 are given it will prompt for parameter 3 and 4; if only one parameter is given it will prompt for parameters 2 to 4; if no parameters are given then it prompts for all 4.
  The year must be a 4 digit number greater than 1870 and smaller than 2020. The other parameters are strings.
  Upon success, the add command reports "Successfully added a record to the database".
  


• view all
view single number
view range number1 number2
  allows the user to view all records, just a single record or a range of records in the database. To view a single record the record number is specified after the keyword "single". To view a range of records the 2 numbers after the keyword "range" indicate the start and the end of the range, they are inclusive. The second number must be larger than the first.
  The output of the view command lists records in the database. The first line of output always is the title text from the database. Then follow the lines for the requested entries in the database, either all, a single line, or a range.
  An example "view all" output looks like this:

     Automobile Database
     Ford, Mustang, 2008, blue with white stripes
     Mitsubishi, Lancer, 2009, white
     Toyota, Camry LE, 2004, black
     Porsche, Cayenne S, 2007, red
  

  An example "view range 2 3" output looks like this:

     Automobile Database
     Mitsubishi, Lancer, 2009, white
     Toyota, Camry LE, 2004, black
  

• delete all
delete single number
delete range number1 number2
  allows the user to delete records: either all, just a single record or a range of records. To delete a single record the record number is specified after the keyword "single". To delete a range of records the 2 numbers after the keyword "range" indicate the start and the end of the range, they are inclusive. The second number must be larger than the first.
  The delete command reports the number of lines deleted, such as "Successfully deleted 4 records from the database". Note that the title line in the database is never deleted.

Error checking

• ensure that the command is spelled correctly
• ensure that all required parameters to the appropriate command are present
• ensure that line numbers fall within the lines present in the database file
• ensure that the database file exists and is readable, and in the case of "add", "delete" and "edit" also writable
• if the file is empty (i.e., no records), your script should print out a message that no records are found

Database file format

For example, the database file for the above "view all" command would contain:

Automobile Database
Ford, Mustang, 2008, blue with white stripes
Mitsubishi, Lancer, 2009, white
Toyota, Camry LE, 2004, black
Porsche, Cayenne S, 2007, red

Example run

a132436@turing:~/unix/assign4$ ./autodb DB create Example for Assignment
New database created

a132436@turing:~/unix/assign4$ ./autodb DB add Ford Mustang 2008 "blue with white stripes"
Successfully added a record to the database
a132436@turing:~/unix/assign4$ ./autodb DB add Mitsubishi Lancer 2009 white
Successfully added a record to the database
a132436@turing:~/unix/assign4$ ./autodb DB add Toyota "Camry LE" 2004 black
Successfully added a record to the database
a132436@turing:~/unix/assign4$ ./autodb DB add Porsche "Cayenne S" 2007 red
Successfully added a record to the database

a132436@turing:~/unix/assign4$ ./autodb DB view all
Example for Assignment
Ford, Mustang, 2008, blue with white stripes
Mitsubishi, Lancer, 2009, white
Toyota, Camry LE, 2004, black
Porsche, Cayenne S, 2007, red

a132436@turing:~/unix/assign4$ ./autodb DB delete single 2
1 record deleted

a132436@turing:~/unix/assign4$ ./autodb DB view all
Example for Assignment
Ford, Mustang, 2008, blue with white stripes
Toyota, Camry LE, 2004, black
Porsche, Cayenne S, 2007, red

a132436@turing:~/unix/assign4$ cat DB
Example for Assignment
Ford, Mustang, 2008, blue with white stripes
Toyota, Camry LE, 2004, black
Porsche, Cayenne S, 2007, red

Additional notes:

• Be sure to test your script thoroughly.
• Your file must mention either /bin/sh or /bin/bash in its shebang line.
• Make sure your script does not leave any temporary files behind.
• Make sure that your autodb file is a regular Unix text file.