1. Special Registers, Date functions, Case and User Defined Functions!!

2. Agenda Review ISeries installed products
Special Registers – System Values
Create Tables
Date Functions
Case
Building our own SQL Functions

3. Review Table vs *FILE Library vs Collection What is a schema?
Constraints?

4. ISeries installed Products
Display Software Resources

5. Build the following Database
Students
Student Number
Student Name
Address
Enrolled Date
Student Marks
Student Number
Course Code
Final Grade

6. Insert Data

7. Add 1 year, 2 months and 3 days to enrolled date
Select Statement
As?

8. How many days has a student been at Seneca?
Select Statement

9. Case Statements Provides a multiconditional test Eg: select orderid,
when totamt <= 100 then ‘Small’
when totamt <= 500 then ‘Medium’
else ‘Large’
end as SalesSize
From Sale

10. Case Statements select orderid, case ShipCity
when ‘Toronto’ then ‘Ontario’
when ‘Montreal’ then ‘Quebec’
else ‘Invalid’
end as CustProv
From Sale

11. Write a select statement that produces a student marks report and lists the letter grade

12. Build your own SQL function
First line:
Create Function fname
Where fname is the name for the function.
Second set of lines is used to define input parameters
Eg: (Str char(10), StrLen int)
defines the parameter Str as a 10 characters
and defines the parameter StrLen as an integer

13. UDF cont’d Third line declares the one variable returned
eg: RETURNS CHAR(10)
Means return a 10 character value
Fourth Line declares the language of the function:
Language SQL

14. UDF Cont’d Fifth line: Returns null on null input
Means that if there are no input values to the function, then NULL will be returned.
Sixth line:
BEGIN
Starts the code section of the function

15. UDF Cont’d
Last line
END
Comments start with --

16. Coding functions DECLARE Used to declare variables SET
used to assign values to variables
RETURN
used to return the output parameter

17. Coding Functions
Most built-in SQL functions can be used including case
Case statements must end in end case
Each statement must end in an ‘;’

18. Build a function that calculates a Letter Grade based on a Final Mark

19. Coding UDF create function dbpract.gradeStr (grade dec(5,2))
returns char(2)
language sql
returns null on null input
begin
-- declare variables
declare chargrade char(2);
-- calculate char grade
case
when grade >= 90 then set chargrade = 'A+';
when grade >= 80 then set chargrade = 'A';
else set chargrade = 'F';
end case;
return chargrade;
end