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I have a bunch of tables in a relational database which, obviously, are dependent upon one another due to foreign key relationships. I want to build a dependency tree, traverse it, and output INSERT SQL statements. I need to first output SQL for foreign key tables in my dependency tree first because parent tables will depend on values from their foreign key identifier tables.
Does a binary tree, traversed in postorder, seem suitable for this task?
If a table can be dependent on more than two tables, a binary tree will be insufficient.
Let table A be dependent on tables B, C and D. Then you would have to insert into B, C and D first, i.e. A should have three child nodes in your tree.
I think you need to use a more general tree structure which allows an arbitrary number of child nodes. Traversing this tree structure in post-order should yield the desired results, as you suggested.
Things will start to get messy when your dependency graph contains cycles and you need to defer constraint checking 😉