Nested CDT Data Write

Certified Lead Developer

Not a question, but an interesting topic I found today that I thought was worth sharing. 

A problem that took some experimentation to figure out was that Nested CDTs will fail on write if the inner CDT foreign key column has a NOT NULL constraint in the database. Appian must do some back-end script that writes the Inner CDT first and then runs an UPDATE to configure Foreign Key relationships. Can anyone confirm/seen this issue before?

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  • Can you clarify what kind of relationship you used and what your Cascade behavior was? Typically if you have a CASCADE=REFRESH behavior, then your nested CDT must already have a primary key that exists in the database for it to work.

    For instance, suppose I have Customer M:1 Region with CASCADE-REFRESH. In this example, you can only use existing regions; you cannot insert a region at the same time you insert customer.

    If I misinterpreted your case, can you provide a bit more information about what you tried?

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  • Can you clarify what kind of relationship you used and what your Cascade behavior was? Typically if you have a CASCADE=REFRESH behavior, then your nested CDT must already have a primary key that exists in the database for it to work.

    For instance, suppose I have Customer M:1 Region with CASCADE-REFRESH. In this example, you can only use existing regions; you cannot insert a region at the same time you insert customer.

    If I misinterpreted your case, can you provide a bit more information about what you tried?

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