SqlException: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Clothing_Colors_Products_ProductId". The conflict occurred in database "Clothes_Shop_1", table "dbo.Products", column 'Id'. code example
Example: sqlexception: the insert statement conflicted with the foreign key constraint
In your table dbo.Sup_Item_Cat, it has a foreign key reference to another table. The way a FK works is it cannot have a value in that column that is not also in the primary key column of the referenced table.
If you have SQL Server Management Studio, open it up and sp_help 'dbo.Sup_Item_Cat'. See which column that FK is on, and which column of which table it references. You're inserting some bad data.
Let me know if you need anything explained better!