从.net web.api

Question

基本上，我试图在.Net API中处理唯一约束验证。我在表的两个字段上都有两个唯一的键约束。

如果您在下面看到我的代码，我正在尝试检查记录是否存在。我正在寻找如果记录存在则返回一个布尔值。那可能吗。目前，我正在返回null。

这是最好的方法吗？

[HttpPost]
        [SkipTokenAuthorization]
        [Route("api/classificationoverrides/create")]
        public IHttpActionResult Create(ClassificationItemViewModelCreate model)
        {
            var mgrClassificationService = GetService<MGR_STRT_CLASSIFICATION>();

            var isExists = mgrClassificationService.Where(x =>
                x.MANAGERSTRATEGYID == model.ManagerStrategyId && x.PRODUCT_ID == model.ProductId).FirstOrDefault();

            if (isExists == null)
            {

                var mgrClassficationOverride = new MGR_STRT_CLASSIFICATION();
                if (model != null)
                {
                    mgrClassficationOverride.PRODUCT_ID = model.ProductId;
                    mgrClassficationOverride.LEGACY_STRATEGY_ID = model.LegacyStrategyId;
                    mgrClassficationOverride.STRATEGY_ID = model.StrategyId;
                    mgrClassficationOverride.MANAGERSTRATEGY_TYPE_ID = model.ManagerStrategyTypeId;
                    mgrClassficationOverride.MANAGERSTRATEGYID = model.ManagerStrategyId;

                    mgrClassficationOverride = mgrClassificationService.Create(mgrClassficationOverride);
                }
                return Ok(mgrClassficationOverride);
            }
            else
            {
                return null;
            }
        }