EF Core – Temporal Table 时态表

前言

EF core 6.0 开始有 build-in 的 Temporal Table 支持了.

关于 SQL Server Temporal Table 可以看这篇.

主要参考

What's New in EF Core 6.0 # SQL Server temporal tables

实战

Configuration

可以设置 History Table Name, SysStartTime, SysEndTime
默认是 TableNameHistory, PeriodStart, PeriodEnd

builder.ToTable(b => b.IsTemporal());
//builder.ToTable("Branch", b => b.IsTemporal(b => {
//    b.UseHistoryTable("BranchHistory");
//    b.HasPeriodStart("SysStartTime");
//    b.HasPeriodEnd("SysEndTime");
//}));

Create, Update, Delete

和一般操作一模一样

var branch = new Branch
{
    Name = "Kulai1",
    Address = "Kulai1",
    ContactNumber = "07-5586349"
};
_db.Branches.Add(branch);
await _db.SaveChangesAsync();
await Task.Delay(3000);
branch.ContactNumber = "07-2249129";
await _db.SaveChangesAsync();
await Task.Delay(3000);
_db.Branches.Remove(branch);
await _db.SaveChangesAsync();

Select

全部资料调出来

var branches1 = await _db.Branches.TemporalAll().ToListAsync();

调出某个时间点的资料

var branches2 = await _db.Branches.TemporalAsOf(
    DateTime.SpecifyKind(DateTime.Parse("2021-10-19 13:04:01.7980901"), DateTimeKind.Utc) 
).ToListAsync();

注: 其实只要放进去的是 datetime 就可以了, kind 会直接被忽视掉. 它也不会智能把 Local Time 换去 UTC 哦

调出某个期间的资料

var branches4 = await _db.Branches.TemporalBetween(
    new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc), 
    new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc)
).ToListAsync();
var branches5 = await _db.Branches.TemporalFromTo(
    new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc),
    new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc)
).ToListAsync();

调出某个期间内的资料

var branches6 = await _db.Branches.TemporalContainedIn(
        new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc),
        new DateTime(2021, 10, 19, 13, 4, 7, 284, DateTimeKind.Utc)
).ToListAsync();