Stop Duplicate records in child table

BLOMASKY

I have a parent table "Units" and a child table "UnitLengths" There is an attribute "length" in the UnitLengths table. I want to make sure when the user is adding records in the UL table that there are no rows with duplicate lengths (for this unit.)

Can someone help me with the logic for this rule?

Thanks
Bruce

BenHayat

If EXISTS UnitLengths WHERE (UnitLengths.ParentUnit IS DEFINED AND UnitLengths.ParentUnit = ThisUnit AND UnitLengths.Length=ThisUnitLengths.Length AND UnitLengths.ID<>ThisUnitLengths.ID) Then REPORT ERROR "Legth already exists"

I didn't know what name you had chosen in your UnitLenths table for the Parent Unit table. So I named it "ParentUnit" in my code. You can change it to your name.
I just wrote this from the top of my head. But the logic should work.

BenHayat

BTW Bruce, the naming convention in OOP for Object name is to use a "Singular" name and use "Plural" for collection. In your case Units should be Unit and UnitLengths, should be UnitLength.

Hope this helps!

BenHayat

Bruce, was the code helpful?

BLOMASKY

Sorry Ben, I was traveling all day today.

Yes, the code helped a lot! I had a brain fart and could not think how to do it. One of the best things of Aware is the fact that the users (few as there are) are always avail. to help others. Of the many things that the website says about Aware, "Intuitive" is perhaps, the only one that I don't agree with. Perhaps if I was not a programmer for the last 35 years, and had no previous experience it would be 🙂

Hope you (and the rest of you cool kids) had a great new year. I am having fun learning my way around V7 and am very hopeful that this version will be create a banner year for Aware.

Bruce

BLOMASKY

Ben, regarding the naming of Objects. IMHO as long as your naming is consistent and understandable by others on your development team, then all is good. I have read many articles telling the "proper" way to capitalize, camelCase, pluralize (is that a word?) etc, etc.

I came from Sencha where there is both a model of the data, which was singular and the data store which could contain multiple records which I would pluralize to be able to tell the difference. With Aware the BO is both! It does define the record structure which would make me want to make it singular, but it is also used when retrieving and working with sets of data. Decisions... decisions... Since my tables in SQL from my previous development environment were plural, and since it was better English when I write my queries "Find ALL Customers" vs. "Find ALL Customer" I went with plural.

Bruce

BenHayat

BLOMASKY wrote
With Aware the BO is both! It does define the record structure which would make me want to make it singular, but it is also used when retrieving and working with sets of data.
Bruce

Not Quite...
Let say you have a "Customer" and "Order" Object. And they have Parent/Child relationship (Customer owns Order).
In this case, you will also have a reference in Customer, called "Orders". That is plural, because it's a reference to a "Collection" of Orders. This the place were you name Order in plural format (Orders), but not as a single object.

I do understand coming from legacy system, we used plural for our tables (35 years here too), but if someone were to look at your Aware code, can get confused. For example, I kept telling myself, "It's Unit not Units. Or It's UntiLength not UnitLengths" when I was writing the code to comply with your style. 😃