We have created a new data class i.e ABC-Data-TV which has the below Properties

1. Doesnt below to a class group

2. Concrete

This is having a dedicated table and created its history table properly.

Now we have to create another class below it ABC-Data-TV-DM with the same properties

1. Doesnt below to a class group

2. Concrete

This should also have its dedicated table

But it is throwing error while creating the History class against it 

Unable to open an instance using the given inputs: pxObjClass = "Rule-Obj-Class", pyClassName = "ABC-Data-TV-DM"

And these errors are shown on class

This record has 2 error(s) in 1 place(s) .

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Save failed - Trying to save an invalid page: Table does not exist in database Trying to save an invalid page: page is not valid

This is due to History table not created properly

Is this way of creation not correct ? Cant we have parent child relationship between 2 concrete classes or there is some other issue