Week 3 · Data audits & API trust boundary · about 3 minutes
What you will be able to do
Read the system catalog to map an undocumented ticket database before writing integration code.
The idea
When the customer's schema is undocumented, do not guess from sample rows. Ask the catalog: which tables exist, which columns are not null, and which foreign keys tie tickets to users.
information_schema and pg_catalog are the map. One afternoon of forensics beats two weeks of wrong assumptions in the AI layer.
SELECT table_name
FROM information_schema.tables
WHERE table_schema = 'public'
ORDER BY table_name;
SELECT tc.table_name, kcu.column_name, ccu.table_name AS foreign_table
FROM information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage AS kcu USING (constraint_name)
JOIN information_schema.constraint_column_usage AS ccu USING (constraint_name)
WHERE tc.constraint_type = 'FOREIGN KEY';If you cannot name the join path from ticket to owner, you are not ready to expose it to the model.
Key takeaways
- Undocumented databases still have a map in information_schema.
- List tables, nullability, and foreign keys before you integrate.
- Do not invent a schema the customer does not run.
Part of the Forward Deployed Engineer roadmap. New to the role? Start with what a Forward Deployed Engineer does.