hello guys i want to remove sql_constraint of barcode since now i want i have product with same barcode, can someone help me? thanks :D

_sql_constraints = [

        ('barcode_uniq', 'unique(barcode)', "A barcode can only be assigned to one product !"),

    ] 

i've done do this bellow code but it raise an error for: "Fail Connect Server"

_sql_constraints = [

        ('barcode_uniq', 'Check(1=1)', "A barcode can only be assigned to one product !"),

    ]