SQLite 3.27

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PRAGMA foreign_keys = ON;
CREATE TABLE Heap ( 
  id INTEGER PRIMARY KEY,
  name TEXT NOT NULL UNIQUE CHECK(typeof(name) = 'text'),
  parent INTEGER REFERENCES Heap(id),                                       
  color INTEGER CHECK(color BETWEEN 0 AND 2)                                                           
); 
INSERT INTO Heap (name, parent, color) VALUES ('name1', null, 1)
INSERT INTO Heap (name, parent, color) VALUES ('name2', 1, 1)
SELECT * FROM Heap


id
name
parent
color


1
name1
null
1

2
name2
1
1


INSERT INTO Heap (name, parent, color) VALUES ('name3', 5, 2)


id
name
parent
color


1
name1
null
1

2
name2
1
1


FOREIGN KEY constraint failed

INSERT INTO Heap (name, parent, color) VALUES ('name3', null, 2)
INSERT INTO Heap (name, parent, color) VALUES ('name4', 2, 1)