Is editing also possible like the cascade delete. in ADF

Question

Hi
I am trying to achieve following requirement.
2)     For a valid edit equipment scenario:-
a. When we increase the equipment count (i. e. availability_count), corresponding equipment instances should also be increased in the T_EQUIPMENT_INSTANCE.
b. When we decrease the equipment count (i.e. availability_count), corresponding equipment instances should also be decreased in the T_EQUIPMENT_INSTANCE.
Here I have two table in DB Viz. T_special_equipment(equipment_id,equipment name, equipment_desc, ...., availability_count) , here equipment _id is generated through the sequence i.e. not getting value from the portal
there is another table T_equipment_instance(Equipment_id, Instance_id) in this table instance_id is generated through sequence.
**Here say currently I have availability_count =3 for equipment_id 100 in T_special_equipment table then this Equipment id would be appearing 3 times in Tequipment_instance table ,** so while perfrming edit operation on
T_special_equipment table and say decreasing availability_count =2 , so correcsponding Equipment id should appeare 2 times in Tequipment_instance table
and suppose while perfrming edit operation on T_special_equipment table and say increasing availability_count =6 , so correcsponding Equipment id should appeare 6 times in Tequipment_instance table
Can anyone please give some suggetions on it, How can I achieve this.

Answer 1

Lets try again:
Start withT_EQUIPMENT_INSTANCE
Row equipment_id        equipment name ....  availability_count
1   1                   Test                 5
T_equipment_instance
Row    Equipment_id        Instance_id
1      1                   100
2      1                   101
3      1                   102
4      1                   103
5      1                   104set availability_count to 3
T_EQUIPMENT_INSTANCE
Row equipment_id        equipment name ....  availability_count
1   1                   Test                 3
T_equipment_instance
Row    Equipment_id        Instance_id
1      1                   100
4      1                   103
5      1                   104or may be
T_EQUIPMENT_INSTANCE
Row equipment_id        equipment name ....  availability_count
1   1                   Test                 5
T_equipment_instance
Row    Equipment_id        Instance_id
3      1                   102
4      1                   103
5      1                   104or T_EQUIPMENT_INSTANCE
Row equipment_id        equipment name ....  availability_count
1   1                   Test                 5
T_equipment_instance
Row    Equipment_id        Instance_id
2      1                   101
3      1                   102
4      1                   103You see the problem?
You need to specify exactly which rows to delete.
In text: "when availability_count decrements delete as many rows in table T_equipment_instance matching the Equipment_id with the highest instance_id until the count of rows equals the availability_count"
or "when availability_count decrements delete as many rows in table T_equipment_instance matching the Equipment_id with the lowest instance_id until the count of rows equals the availability_count"
or "when availability_count decrements delete as many rows matching the Equipment_id until the count of rows equals the availability_count"
This a use case you can code against.
Next thing is that you said that you use a sequence to fill the instance_id. One feature of a db sequence is that you get each number only once. So when you decrement the availability_count and delete the highest numbers and then increment the availability_count again the instance id has gaps.
Timo