# Deferrable Constraint

A constraint whose checking may be postponed until transaction completion.

## What does **Deferrable Constraint** do in a relational database?

**Deferrable Constraint** — A constraint whose checking may be postponed until transaction completion.

```sql
ALTER TABLE enrollment
ADD CONSTRAINT enrollment_student_fk
FOREIGN KEY (student_id) REFERENCES student (student_id)
DEFERRABLE INITIALLY DEFERRED;
```

Level: Freelancer · [More Database terms at this level](https://www.ask-codey.com/glossary/subjects/database/freelancer)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/deferrable-constraint