How to fix FOREIGN KEY error?

Question

Database administration

There are two tables /Users/egortimonin/Desktop/Screenshot 2020-07-19 at 15.48.25.png in tblMessage all IDs are unique, but EQUIPMENT_ID can be repeated, when filling the tblMessage table SQL complains and writes

Конфликт инструкции INSERT с ограничением FOREIGN KEY "FK__tblMessag__EQUIP__0559BDD1". 
Конфликт произошел в базе данных "dbo", таблица "dbo.tblEquipment", column 'ID'.

I don't understand why this is happening, I have a one-to-many relationship where one tblEquipment entry can have many entries in the tblMessage table. Why is there an error?

Answer 1

You are adding to a tblMessagestring with a value EQUIPMENT_IDthat is not in tblEquipment.

Answer 2

The screenshot is not visible, but I will assume that you mixed up the direction of the key (i.e. the unique field).