c# – 实体框架不保存对数据库的更改

发布时间：2020-12-15 20:59:18 所属栏目：百科来源：网络整理

导读：我很困惑为什么这个代码不起作用,它应该在循环之后保存对数据库的更改但是当我将SaveChanges方法放在循环中时,它将记录保存到数据库中但是在它之外它不保存任何东西？它只有300~1000条记录 static bool lisReady = false; static bool sacclReady = false; s

我很困惑为什么这个代码不起作用,它应该在循环之后保存对数据库的更改但是当我将SaveChanges方法放在循环中时,它将记录保存到数据库中但是在它之外它不保存任何东西？它只有300~1000条记录

static bool lisReady = false;
    static bool sacclReady = false;

    static void Main(string[] args)
    {
        Logger("Starting services");
        ConnectDBLis().Wait();
        ConnectDBSaccl().Wait();
        Thread.Sleep(1000);
        if (lisReady & sacclReady){
            //start
            Logger("Services ready");
            StartExport().Wait();
        }
    }

    static async Task<bool> StartExport()
        {
            lis lisdb = new lis();
            nrlsaccl saccldb = new nrlsaccl();
            var getTestOrders = await lisdb.test_orders.ToListAsync();
            Logger("Services starting");
            foreach (var tO in getTestOrders.Where(x => x.entry_datetime.Value.Year == 2016))
            {
                foreach (var tr in tO.test_results)
                {
                    foreach (var tL in tr.test_result_logs)
                    {
                        results_availability postResults = new results_availability
                        { 
                          first_name = tO.patient_orders.patient.first_name,middle_name = tO.patient_orders.patient.middle_name,last_name = tO.patient_orders.patient.last_name,birthdate = tO.patient_orders.patient.birthdate,};
                        if (postResults.id == 0)
                        {
                            saccldb.results_availability.Add(postResults);
                        }
                        else
                        {
                            saccldb.Entry(postResults).State = EntityState.Modified;
                        }
                    }
                }
            }
            await saccldb.SaveChangesAsync();
            return true;
        }

编辑：

所以我将记录限制为100并保存更改有效,瞬间3000条记录不起作用,任何解决方案？

解决方法

此代码无法完全解决您的问题,这是您的问题的一些考虑因素.

注意：这在添加1200条记录和300条修改时适用于我

static async Task<bool> StartExport()
    {
        using (var db = new Entities())
        {
            var appraisals = await db.Appraisals.ToListAsync();

            db.Database.CommandTimeout = 300;
            //Disabling auto detect changes enabled will bring some performance tweaks
            db.Configuration.AutoDetectChangesEnabled = false;
            foreach (var appraisal in appraisals.Where(g => g.Id > 1))
            {

                if (appraisal.Id == 10)
                {
                    appraisal.AppraisalName = "New name";
                    db.Entry(appraisal).State = EntityState.Added;
                }
                else
                {
                    appraisal.AppraisalName = "Modified name";
                    db.Entry(appraisal).State = EntityState.Modified;
                }
            }

            db.Configuration.AutoDetectChangesEnabled = true;

            if (await db.SaveChangesAsync() > 1)
                return true;
            else
                return false;
        }
    }

You could use db.Database.CommandTimeout = 300; to increase the timeout of you connection.

Entity framework 6 provides AddRange() This will insert the items in one shot,it will disable AutoDetectChangesEnabled and insert the entities

在您的情况下,您不希望将entites标记为已修改,EF已经很好地跟踪它. Entity Framework – Why explicitly set entity state to modified?

The purpose of change tracking to find that you have changed a value on attached entity and put it to modified state. Setting state manually is important in case of detached entities (entities loaded without change tracking or created outside of the current context).

在这里,我们将所有实体附加到上下文本身

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!