SQL and PLSQL

Before you start this coursework you must have finished the SQL exercises on the Bus/ Depots / Drivers Database.
Important note - check that you have not, in preceding modules, created tables with the same names as in this exercise. If any of these table names already exist in your area in Oracle then you should either delete them (using ‘drop table xyz cascade constraints’) or use different names for tables in the coursework database. There might also be problems if constraint primary key and foreign key names are the same so it is advisable to delete all tables created in preceding modules. After creating and loading tables check that all data is present.
Employ Oracle SQL*PLUS to answer the following queries. It is recommended which you either use Notepad or similar (not Word) to initially create the queries.

The Children’s Library Database

This situation relates to a database that is to be set for a library that lends books to children:

A Children's Library keeps information on books held, borrowers who borrow these books and the loans of these books, which the borrowers make. In addition information is held regarding the authors and publishers of these books.

The information is to be held in a Relational database and implemented using Oracle. Two files are available on Oasis Plus for you to make the relations and to load the relations with sample data.  The tables in the database are shown. The identifier attribute(s) are underlined, foreign keys are asterisked *.

Table                                  Attributes
Borrower    borId, borName, borAddress, borMaxbooks

BookTitle    isbn, btName, datePublished, pubId*, ageLower ageUpper, value

BookCopy    bcId, isbn*, dateAcquired, dateDestroyed

Loan                borId*, bcId*, dateOut, dateDue, dateBack

Publisher    pubId, pubName, pubAddress

Author                   authorId, authorName

Authorship    authorId*, isbn*

Note that the BookCopy table contains information on the physical books kept in the library whereas the BookTitle table contains information on a specific publication of a book. For ex, there are two copies of 'Winnie the Pooh', with bcId of 101 and 102 with an ISBN (International Standard Book Number) of 10: 0786843411.  The BookTitle table contain information regarding the recommended age range for each book (ageLower and ageUpper). A book might have a number of authors and this is indicated in the Authorship table.

The characteristic borMaxbooks points to the maximum number of books that a borrower can borrow at a time. Also, a book, which is still out on loan, will have a blank dateBack field in the loan table.

As copies of books become old, damaged and dirty the books are deleted from the library and destroyed. Destroyed book copies have a date to indicate this otherwise the date is null.

It is essential which you draw an Entity-Relationship diagram mapped to a relational database, showing the entities and relationships included. Suppose that features with the same name are based on the same domain. Do not hand in this diagram – it is not assessed.

Use join conditions to answer the queries in this problems 1 and 2

Q1. Find out borrowers (by name) who have ever borrowed a book written by the Phillip Pullman.

Q2. Find out borrowers (by name) who have currently on loan a book written by the Phillip Pullman

Q3. Give the ISBN and title of every book and the number of copies currently on the loan listing most popular first.

Q4 Display the names of borrowers who have never borrowed books published by the publisher Mammoth.

Q5. Give the titles of books that have the same value as ‘Northern Lights’. Do not comprise Northern Lights in your output.

Q6 List out all book titles and the total value of the book copies for a particular title that are currently on loan where total value is greater than or equal to £20.

Q7. List out the borrowers (by number and name, once only), who have currently on loan a book that has the same title as a book that Jenny Wren has borrowed. Do not comprise Jenny Wren in the output.

Q8. Provide the name of any borrower who has ever borrowed all the book copies in the library. It is possible that no-one has borrowed all the copies. (Hint: this is an ex of relational algebra divide).

Q9. Run the make View statement and the query below and show the results. Give the English meaning of the query (as in problems 1-7 above):

Create view borrowedBooks

As     Select l.borId, bc.isbn, bc.bcId
        From Loan l, bookCopy bc
        Where l.bcId = bc.bcId;

Select b.borName
From Borrower b
Where not exists
    (select *
    from bookTitle bt, Publisher p
where bt.pubId=p.pubId
and pubName='Puffin'
    and not exists
        (select *
        from borrowedBooks bb
        where bb.borId = b.borId
        and bb.isbn = bt.isbn));

Q10. Run the query below and demonstrate the results. Provide the English meaning of the query (as in problems 1-7 above):

Select distinct                   b.borName
From  Borrower           b, Loan l, Book_copy bc,
Author                              a1, Author a2,
Authorship                  ash1, Authorship ash2
Where                            b.borId = l.borId
And                                l.bcId = bc.bcId
And                        bc.isbn = ash1.isbn
And                    bc.isbn = ash2.isbn
And               ash1.authorId = a1.authorId
And                ash2.authorId = a2.authorId
And                a1.authorName = 'Janet Ahlberg'
 And              a2.authorName = 'Allan Ahlberg';

Triggers and stored procedures

Don’t forget to type the command ‘set serveroutput on’ before implementing the code in this section. If you are forced out of the SQL*PLUS don’t forget to retype this command.

Before you start this coursework you must have completed the PL/SQL exercises on the Bus/Drivers/Depots Database.

1. prepare down a PL/SQL block which comprises a procedure getTotalLoans which accepts a ISBN and returns the title and number of copies currently on loan for that book. (See problem 3 of the SQL queries part of the coursework.) The main block must call the procedure with an ISBN of 4 and output the book title and number of copies.

2. prepare down a PL/SQL block, which displays for all book titles held in the library (not those destroyed). You should include the ISBN, the book title, publisher name and the number of copies of each held (whether on loan or not). Use a cursor to do this problem.

3. prepare down a stored function called getPublisher. This function takes up as input an ISBN for a book and returns the publisher name.
Call the function from within an SQL statement to display the publisher for book title ‘The Twits’

4. Make a trigger ‘checkRecommendedAge’ to enforce the (harsh) constraint that children are only permitted to borrow books deemed suitable for their age. The trigger fires whenever there is a new loan and outputs an error message whenever an attempt is made to borrow a book where the borrower’s real age is not in the lower to upper age range for the book. Ignore the fact that some of the data already in the database may violate the constraint.

Show what happens when you try to insert following records into the Loan table using the following statements:

Insert into Loan values (001,144,'29-aug-2008','18-sep-2008','');
Insert into Loan values (001,101,'29-aug-2008','18-sep-2008','');
Insert into Loan values (001,120,'29-aug-2008','18-sep-2008','');
For testing purposes the following commands (which set the database back to its original state) might be useful:
delete from Loan where borId=001 and bcId=144 and dateOut='29-aug-2008';
delete from Loan where borId=001 and bcId=101 and dateOut='29-aug-2008';
delete from Loan where borId=001 and bcId=120 and dateOut='29-aug-2008';
Note well: read following page before handing in your coursework

- For SQL coding, indication of the problem a particular solution refers to, written as a comment e.g. /* problem 1 List the borrowers……*/

- For PLSQL coding  the problem number is required only

- The SQL and PLSQL code in its entirety, formatted with indentations so it is easy to read (see code in text book). Please use a reasonable size of font.

- SQL*Plus Screen print to verify that you have executed the code

- The resulting table created from the SQL execution or results from your PLSQL execution.  You should copy and paste the results from SQL*Plus. If the output is very long, hand in the first page only. Note that the correct solutions generate small tables.  Do not print/hand in