Is there a clean, simple, and preferably prepackaged (ready function?) way to list the order of referential integrity in a Postgres database, rather than trying to read the system tables to find that order manually, which is tedious and time consuming?

What I mean is, if the entity hierarchy is


meaning that a single user can have multiple accounts and that a single account can have multiple transactions, if I want to delete all the three tables without breaking any foreign keys, I would have to do it in the exact following order:


Now this is a very simple and obvious example. But real life databases have a lot more tables and foreign keys. If I wanted to delete every table down to 0 rows, is there a quick way to obtain the exact order of referential integrity to do it in?

  • 3
    Write a script to do data dictionary diving, given a table name? – Philᵀᴹ Oct 14 '16 at 15:08
  • i was hoping this function could be prepackaged – amphibient Oct 14 '16 at 15:14
  • also, i am not familiar with the term data dictionary diving – amphibient Oct 14 '16 at 15:15
  • There nay be cycles in the foreign keys graph (a table referencing itself or A -> B -> C -> A) – ypercubeᵀᴹ Oct 14 '16 at 16:18
  • i get that @ypercubeᵀᴹ. but wouldn't that be indicative of a less-than-perfect DB design (which is a separate issue from the one at hand) ? – amphibient Oct 14 '16 at 16:22

You can "dive" into the system tables and get all the tables that reference a specific table (and all those that reference them, etc). It will be a recursive query, not very difficult to write.

However, for the simple operation you want to to perform, there is a simple solution:
TRUNCATE with the magic option CASCADE:

truncate table a cascade ;

Tested at rextester.com

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