Third Normal Form (3NF) is the point in the normalization process where you remove dependencies that travel through an intermediate attribute. A transitive dependency occurs when a non-key attribute determines another non-key attribute, so the second attribute depends on the primary key only indirectly. A classic pattern looks like this: in an Employee table keyed by EmployeeID, the DepartmentID determines DepartmentName, so DepartmentName depends on EmployeeID only through DepartmentID. The fix is to split the dependent attributes into their own table and keep the determinant as a foreign key.
In this course, 3NF matters because it is the practical stopping point for most production schemas. Once a table is in 2NF, leftover transitive dependencies are what still cause redundant storage and the insertion, update, and deletion anomalies you studied earlier in the module. Decomposing to 3NF keeps each fact recorded in exactly one place, which makes updates safe and keeps referential integrity meaningful.
As you watch the videos below, pay attention to three things: how each presenter identifies the determinant of a suspect attribute, how the original table is split (which attribute stays behind as a foreign key), and how the resulting tables are checked against the 1NF and 2NF rules you already know. Try pausing before each worked solution and attempting the decomposition yourself, then compare your answer to the presenter's.
This lecture walks through the full sequence of normal forms, from 1NF through BCNF and the higher forms, using everyday example tables rather than abstract notation. The 3NF portion should show how transitive dependencies are identified and why 3NF builds directly on the 2NF requirements. Because it covers everything in one pass, it also places 3NF in context relative to what comes before and after it.
Gate Smashers is a widely used computer science channel, and this single-session overview is useful for seeing how 3NF fits into the whole normalization ladder rather than treating it as an isolated rule.
A short, exercise-driven video that takes a denormalized dataset and works it into Third Normal Form step by step. The description also indicates coverage of denormalization, so you should see why designers sometimes deliberately reverse the process for performance reasons. Expect a worked table transformation rather than a lecture on theory.
Its practice-problem format directly supports the "Decomposing Tables to Achieve 3NF" and "Step-by-Step 3NF Transformation Example" subtopics, and the brief running time makes it easy to replay while attempting the exercise yourself.
Part four of a database design series, this video states the 3NF rule explicitly: a table is in 3NF when it satisfies all 2NF rules and no non-key attribute determines another non-key attribute. The longer format allows a careful, definition-first treatment of the rule and its application to sample tables. It assumes you have watched the earlier parts on 1NF and 2NF, which matches the order of this module.
Hugo Kornelis is a veteran database professional, and the precise phrasing of the rule in the video description signals the kind of careful definition students need for recognizing 3NF violations and validating a finished schema.
Together these videos carry you from recognizing a problem to fixing and verifying it. The Gate Smashers overview and the Kornelis lesson give you the precise statement of the 3NF rule and the reasoning about anomalies and dependencies that supports MO1 and MO4, while their reviews of the earlier normal forms reinforce the 1NF and 2NF work in MO2 and MO3. The Tech Coach practice exercise provides the hands-on decomposition drill called for by MO4, and the cumulative, build-on-the-previous-form structure of all three videos models the compliance check across every resulting table that MO5 requires.
These videos were chosen from YouTube on October 2, 2026. Each has captions; the player turns them on. Videos on YouTube can be changed or removed — if one no longer plays, tell your instructor. If a player does not appear, use its Watch on YouTube link.