Need a Constrain

The sample you sent does not have the WBS_5 table. Can you upload another one?

Rafael said:
The Constrain in Level 5 is : a.'Level-4' = b.'Level 4' not work. 

 Double check that you have the correct field in the b section. There is no 'Level 4' field in the WBS_5 table. There is a WBS_4 field.

To lock records I use this process.

1.  Create a button to unlock a record with this in On Click:

do as server
    for i in (select 'YourTableName')[LOCKED = true or LOCKED = null] do
        i.(LOCKED := false)
    end
end;
alert("All records unlocked")

2.  Create another button to lock a record with this in On Click:

do as server
    for i in (select 'YourTableName')[LOCKED = false or LOCKED = null] do
        i.(LOCKED := true)
    end
end;
alert("All records locked")

Note:  The above locks ALL records in 'YourTableName'

For each of these buttons I use a lock/unlock emoji 

I have a Windows PC and use Win+; to find an emoji.

3.  Create a Yes/No field named 'LOCKED'.  This allows me to Lock/Unlock a single record and is triggered by the above.  The code in 1 and 2 above toggles the LOCKED - Yes/No field.

4.  In every field I want to respond to the Locked status I have added this "not LOCKED" (omit "") in the Writable If condition.

5.  As a safety measure I also have added the code in point 2 (without the alert) to the Trigger after hide parameter of the TAB for the form.  This of course assumes you have a TAB as the first element of your form (I do so I can have a background colour for TABS)

Hope that helps.