About this tool
Name two entities, choose the relationship type and the participation on each side, and the tool shows which symbol each notation uses and generates the tables that relationship becomes. Crow's foot notation writes both the minimum and the maximum using bars, circles and a three-pronged foot, while UML writes a numeric range such as 0..1 or 1..*. Chen notation is a different family that draws the relationship as a diamond and writes 1 and N along the lines.
The heart of turning a relationship into tables is where the foreign key goes. A 1:N puts it on the many side, and a 1:1 needs UNIQUE on top of that to be distinguishable from 1:N. An N:M cannot live in two tables, so a junction table is created with both foreign keys bound into a composite primary key. The behaviour when a parent row is deleted can be picked from the five actions standard SQL defines as of October 2026, with a note on why the chosen one behaves as it does.
The tool also points out rules a foreign key cannot hold. Requiring that each side has at least one counterpart is not something a foreign key can enforce. It does not draw diagram pictures, and it does not design data types or indexes, check naming rules or judge normal forms.
Frequently asked questions
They are two names for the same notation. The information engineering name came first, and because the many end splits into three prongs like a bird's foot it is also called crow's foot. Chen notation is a separate family that draws relationships as diamonds, so its symbols genuinely differ.
A column holds one value, so a relationship with many on both sides cannot fit into two tables. A separate table with one row per pair, keyed on both foreign keys together, stores the relationship and prevents the same pair appearing twice.
It does not draw diagram pictures, design data types or indexes, check naming rules or judge normal forms. It compares notation symbols and generates table definitions.