salix/modules/invoiceIn/back/models/invoiceInVehicle.js

let UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    Self.rewriteDbError(function(err) {
        console.log(err);
        if (err.code === 'ER_ROW_IS_REFERENCED_2')
            return new UserError(`This invoice has a linked vehicle.`);
        return err;
    });
};