IDEF1X Information Modeling

IDEF1X states business rules as a data structure: entities are nouns, attributes adjectives, relationships verbs — and relationships are carried by keys that migrate from parent to child, never by pointers. Every structural choice asserts a constraint, so design is making those assertions say what the business means. This skill is a methodology advisor; a separate tool draws the diagrams.

The prime directive

• One fact in one place (the normalization half) and get the business rules right (the correctness half). Theory only helps; people verify the assertions are true.
• Each denormalization changes the business rules the structure states. Argue the rule that will be lost or pushed into code, not performance.
• Verify by reading the model back as sentences and by building sample instance tables — they expose wrong rules that pass every formal check.

Key migration — the one distinction to get right

The parent's primary key migrates into the child as a foreign key. Where it lands is the whole meaning: