Form Validation against DB

Question

Hi,
I have a field to capture the username and would like to validate against the database that it is a valid user before submitting. If not, I will show an error message. Are there any good example of doing that in Apex? Thanks.

Answer 1

Hi
There are several ways you could do this. A simple method would be to add an Item Level Validation on your page for the username field.
1 Click the Create button in the Validations section of the page defniition
2 Select Item level validation
3 Select the username field from the list of page items
4 Select SQLvalidation method
5 Select the Exists type
6 Give the validation a name (eg, Validate username) and select a location for any error message
7 In the Validation setting, enter in something like:
SELECT 1 FROM USERTABLE WHERE UPPER(USERNAME) = UPPER(:P1_USERNAME)and enter in an Error Message - (eg, Invalid username)
8 Select the button that is used to submit the page (eg, SUBMIT)
9 Click Create to finish
Then, whenever the user clicks the Submit button, the vaildation is triggered and an attempt is made to find the username entered in your list of valid usernames - if there is a match, the above SQL will return one row and the validation is deemed to have passed, so the submit takes place. If there isn't a match, no rows will be returned and the validation fails, and the error message is displayed and the submit process stops.
Andy