This project involves setting up a database for car records, similar to the one used by the State Department of Motor Vehicles. Attached is the source code for an interactive user interface program, proj_09ui, and the spec and body of a package cars.
proj_09ui, in operation, looks something like this:
Select one operation below: C -> Table, Commit Table R -> Table, Rollback Table S -> Table, Select all Rows T -> Table, Truncate Table A -> Row, Add One Row D -> Row, Delete One Row F -> Row, Find a Row U -> Row, Update One Row Q -> Quit the Program
Please type a command, then press Enter > C Thank you for correct input.
You'll find it easiest to do the project step-by-step, as follows:
Step 1: Compile these three programs and also the package simple_dates. Then link proj_09ui and run it, just to see how it behaves.
Step 2: Modify simple_dates according to the attached package spec. Use the concepts developed in Project 7.
Step 3: Implement the following task in proj_09ui:
database_writer
The database_writer task reads from input file into the DB_Commit array and the DB_Pending array. The database_writer writes only from the DB_Commit array (every so many seconds, you chose the time interval). We will provide a test data file cars.dat. You will be able to test these operations by running proj_09ui program.
Step 4: Now implement the operations
Commit_Database -- Copy DB_Pending to DB_Commit Rollback_Database -- Copy DB_Commit to DB_Pending Select_Database -- Display all rows in DB_Pending
The database_writer task and the Commit_Database procedure require synchronization -- use the task synchronize_commit for this purpose.
Step 5: Now implement the operations
Put Add_Row Find_Row
so you can read in the data, add a few Add_Row transactions, then display and write the database to disk. You can then examine the disk file with vi or cat. Hint: Rewrite the Procedure Select_Database to use the Procedure Put.
Step 6: Complete the other operations in the database package and tie them into proj_09ui.
The Ada source code files necessary to start this project are stored in the directory "~csada/clund/proj_09". Use the Unix copy ("cp") command to obtain the files.
Here is the Simple_Dates interface with the desired modifications:
WITH Ada.Calendar;
PACKAGE Simple_Dates IS
------------------------------------------------------------------
--| Specification for package to represent calendar dates
--| in a form convenient for reading and displaying.
--| Author: Michael B. Feldman, The George Washington University
--| Last Modified: April 1996
------------------------------------------------------------------
TYPE Months IS
(Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec);
TYPE Date IS PRIVATE;
PROCEDURE Get(Item: OUT Date);
-- Pre: None
-- Post: Reads a date ROBUSTLY in mmm dd yyyy form, returning it in Item
PROCEDURE Put(Item: IN Date);
-- Pre: Item is defined
-- Post: Displays a date in mmm dd yyyy form
PROCEDURE Get(File: IN Ada.Text_IO.File_Type; Item: OUT Date);
-- Pre: None
-- Post: Reads a date in mmm dd yyyy form from the given file,
-- returning it in Item
PROCEDURE Put(File: IN Ada.Text_IO.File_Type; Item: IN Date);
-- Pre: Item is defined
-- Post: Writes a date in mmm dd yyyy form to the given file
FUNCTION Today RETURN Date;
-- Pre: None
-- Post: Returns today's date
PRIVATE
TYPE Date IS RECORD
Month: Months;
Day: Ada.Calendar.Day_Number;
Year: Ada.Calendar.Year_Number;
END RECORD;
END Simple_Dates;