Oracle Forms

Guys,

I am new to forms. I do have a requirement where I need to create one tabular block for 10 rows (parent record) and then I need to create three tabular tabs of 5 rows for detailed records (child). That means each tab can have 5 records for 1 parent row.. Thats how this parent-child structure has ONE to MANY relationships

To achieve this requirement I created one parent block of table type (using table XX_Parent) and then I created three detailed block for each tab (Tab_A,Tab_B,Tab_C) using child table (XX_Child). For each tab while inserting the data I took one context_value column in child table. i.e. when I insert the data using Tab_A , context_value column will be A. In the same way B and C for Tab_B for Tab_C respectively. And I wrote this logic at PRE-INSERT trigger for each tab. But when I insert the data for all the tabs, it allows me to enter successfully for Tab_A only, the moment I navigate from Tab_A to enter the data intoTab_B, it throws me error like "You are passing NULL value to set context_value". I hope I make the requirement clear to you.

I am not sure if I am following the right approach to achieve my requirement. if its not right, please suggest me right one.. and if its right please guide me resolve the error..

Looking forward to your reply.

Thanks
Sunil