1. Relationships and Advanced Query Concepts Using Multiple Tables Please use speaker notes for additional information!

2. Relationships To ensure the integrity of the data, the developer has two powerful tools: 1) Entity integrity which means that the primary key must be unique and that can be no null values in the key. 2) Referential integrity which means any foreign keys established must link to a valid primary key. Referential integrity is an option that the developer can choose to enforce or ignore. Lets say you have an employee table and a dept table. The employee table contains a foreign key of dept which links to the dept table where dept is the primary key. You cannot add an employee to the employee table and assign them to a dept that does not exist in the dept table. If you want a new dept, you must go to the dept table and create the new dept. Then you can add an employee and assign to that dept. To put this into rule form: the primary key must exist in the parent table before you can use a foreign key of that value in the child table. Also you cannot delete a row/record from the parent table that will leave orphans in the child table. Looking at my example above, once you have used the dept in the employee table, you cannot delete the dept from the dept table without first deleting all employees assigned to that dept from the employee table.

3. In this example, I first clicked the relationship button in the toolbar and then in the show tables, I selected the 3 tables shown. I dragged the DDriveNo from the Drive2000 table to the Donation2000 table to establish the relationship and the edit relationship box was shown. If I want to enforce referential integrity, I will click the box. Referential Integrity When the relationships button is clicked, relationships appears on the tool bar. You can use this to show or edit etc. Select tools and then select relationships to get to this screen.

4. Referential Integrity If you click on Join Type, the options shown below are given. This means you can do an equi-join or inner join which joins only those records from two tables that are equal or you can allow records from one table to match another as explained.

5. Relationship I have now established a relationship between the drive number on the Drive2000 table and the drive number on the Donation2000 table. The one side of the one to many relationship is shown with a 1. The many side of the one to many relationship is shown with a 8 This slide shows the additional relationship between idno on the donor2000 table and idno on the Donation2000 table. Again notice the 1 to many relationship.

6. Index Especially for large databases it is beneficial to index the foreign key. In this example, DDriveNo on the Donation 2000 table has been indexed. Because there are many occurrences of DDriveNo it is important to use Yes(Duplicates OK).

7. Donor2000 Shows the entries in Donation2000 that relate to the record in Donor2000.

8. Drive2000 Shows the related records in Donation2000.

9. Donation Because I established referential integrity I cannot add a record on the child side (Donation2000) with a drive number that does not exist on the parent side (Drive2000). In this example, I tried to add a record with drive 127. Drive 127 does not exist in Drive2000 son an error message is displayed and the record is not allowed.

10. 3 table query

11. SQL SELECT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Donation2000.DDateCont, Donation2000.DAmtCont, Drive2000.DDriveName FROM Drive2000 INNER JOIN (Donor2000 INNER JOIN Donation2000 ON Donor2000.DIdno = Donation2000.DIdno) ON Drive2000.DDriveNo = Donation2000.DDriveNo; SELECT Donor2000.DIdno, DName, Donation2000.DDriveNo, DDateCont, DAmtCont, DDriveName FROM Drive2000, Donation2000, Donor2000 WHERE Donor2000.DIdno = Donation2000.DIdno AND Drive2000.DDriveNo = Donation2000.DDriveNo; The first SQL was created by Access, the second is my code.

12. Three tables donation >= 500 Three tables donation >= 500 This query takes data from three tables. The table is in ascending order by Didno and only those records with DAmtCont >= 500 are shown.

13. SELECT Donation2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Drive2000.DDriveName, Donation2000.DAmtCont FROM Drive2000 INNER JOIN (Donor2000 INNER JOIN Donation2000 ON Donor2000.DIdno = Donation2000.DIdno) ON Drive2000.DDriveNo = Donation2000.DDriveNo WHERE (((Donation2000.DAmtCont)>=500)) ORDER BY Donation2000.DIdno; SELECT Donation2000.DIdno, DName, Donation2000.DDriveNo, DDriveName, DAmtCont FROM Donation2000, Drive2000, Donor2000 WHERE Donation2000.DIdno=Donor2000.DIdno AND Donation2000.DDriveNo=Drive2000.DDriveNo AND DAmtCont>=500 ORDER BY Donation2000.DIdno; SQL for three tables - donation >= 500 The SQL code above was generated by Access, the code below was written by me. The results are the same.

14. Parameter Query I keyed in the >= and then square brackets surrounding the prompt for data. When you run, the prompt asks for the number to test.

15. SELECT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Drive2000.DDriveName, Donation2000.DAmtCont FROM Drive2000 INNER JOIN (Donor2000 INNER JOIN Donation2000 ON Donor2000.DIdno = Donation2000.DIdno) ON Drive2000.DDriveNo = Donation2000.DDriveNo WHERE (((Donation2000.DAmtCont)>=[Enter number to test])); SELECT Donor2000.DIdno, DName, Donation2000.DDriveNo,DDriveName, Donation2000.DAmtCont FROM Donor2000, Donation2000, Drive2000 WHERE Donor2000.DIdno = Donation2000.DIdno AND Drive2000.DDriveNo = Donation2000.DDriveNo AND DAmtCont>=[Enter number to test]; SQL from parameter query The SQL at the top was generated by Access for the parameter query. The SQL below is my code.

16. Parameter - between In this test you can see that Low amount was entered as 500. When prompted for High amount, I entered 1000.

17. SELECT Donor2000.DIdno, Donor2000.DName, Donation2000.DIdno, Drive2000.DDriveName, Donation2000.DAmtCont FROM Drive2000 INNER JOIN (Donor2000 INNER JOIN Donation2000 ON Donor2000.DIdno = Donation2000.DIdno) ON Drive2000.DDriveNo = Donation2000.DDriveNo WHERE (((Donation2000.DAmtCont) Between [Low amount] And [High amount])); SELECT Donor2000.DIdno, DName, Donation2000.DIdno, DDriveName, DAmtCont FROM Donor2000, Donation2000, Drive2000 WHERE Donor2000.DIdno = Donation2000.DIdno AND Drive2000.DDriveNo = Donation2000.DDriveNo AND DAmtCont Between [Low amount] And [High amount]; Code above generated by Access. Code below written by me. SQL Parameters

18. Calc

19. SELECT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Drive2000.DDriveName, Donation2000.DAmtCont, [Donation2000]![DAmtCont]*1.1 AS Goal FROM Drive2000 INNER JOIN (Donor2000 INNER JOIN Donation2000 ON Donor2000.DIdno = Donation2000.DIdno) ON Drive2000.DDriveNo = Donation2000.DDriveNo; Calculation SELECT Donor2000.DIdno, DName, Donation2000.DDriveNo, DDriveName, DAmtCont, DAmtCont*1.1 AS Goal FROM Donor2000, Donation2000, Drive2000 WHERE Donor2000.DIdno = Donation2000.DIdno AND Drive2000.DDriveNo = Donation2000.DDriveNo; Generated code above. My code below.

20. SELECT TOP 25 PERCENT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Donation2000.DDateCont, Donation2000.DAmtCont, Drive2000.DDriveName FROM Drive2000, Donation2000, Donor2000 WHERE (((Donor2000.DIdno)=[Donation2000].[DIdno]) AND ((Drive2000.DDriveNo)=[Donation2000].[DDriveNo])); High/Top Values This code shows the use of the top or highest values button. Note that I selected 25% which now appears in the SQL code and that only the top 25% of the records are showing - there is a total of 10 records.

21. SELECT TOP 10 PERCENT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Donation2000.DDateCont, Donation2000.DAmtCont, Drive2000.DDriveName FROM Drive2000, Donation2000, Donor2000 WHERE (((Donor2000.DIdno)=[Donation2000].[DIdno]) AND ((Drive2000.DDriveNo)=[Donation2000].[DDriveNo])) ORDER BY Donation2000.DAmtCont DESC; Top 10% contribution

22. High values SELECT TOP 25 PERCENT Donor2000.DIdno, Donor2000.DName, Donation2000.DDriveNo, Donation2000.DDateCont, Donation2000.DAmtCont, Drive2000.DDriveName FROM Drive2000, Donation2000, Donor2000 WHERE (((Donor2000.DIdno)=[Donation2000].[DIdno]) AND ((Drive2000.DDriveNo)=[Donation2000].[DDriveNo])) ORDER BY Donation2000.DAmtCont;