Check for duplicate before insert

Hi,

I was wondering if there is any simple guide or tutorial on how to implement a check to prevent a simple form from inserting its values to the database if there is a duplicate?

I created an simple insert form and set in my database the 'name' column to be unique.
I used a DataAssist insert behavior to insert the form values into the database.
How can i make the insert behavior to first check the 'name' field for duplicates before really inserting and if there is already a dulicate to show the message that the name already exist and need to choose another name.

Does this involve handcoding or does DataAssist has such feature inside to check first.

I hope someone can give some easy tutorial how to do this.

Thanks.

Ok, i figured it out how to do it, works nicely!

I just had to move the lookup record set above all the validation code otherwise it would not let me insert any values and always showed the error validation for the lookup.
Now it is working like a charm.

Just one question, when i enter some error message and select it to create the showif behavior it will generate the code nicely. I just wonder if you always need to select the correct class in the property inspector to create the same span tag with the same look like the other error messages which were created when inserting the form.
Also i found when selecting this class manually it does create the correct look but does not insert the id field, has this to be coded by hand as well?

Thanks.

yes, the span tag will need to added to the message after it is added.

this helped me