Query of the history of a temporary table returns additional records

File a bug

Imagine that you have a simple invoices and InvoicesHistory entities, also imagine that you have already inserted some records (only inserted, not updated ).

So if you query from SQL Server Management Studio (SSMS), the [InvoicesHistory] table has no records. (Of course, because there were no updates)

The surprise is that if you query from EFC , as many records as the temporary table has are retrieved. i.e

Query from SSMS Invoices has 5 insertions, InvoicesHistory has 0 insertions (because Invoices were no updates)

The surprise is that if you query the InvoicesHistory table from EFC, it returns 5 records. (for this example)

 var invoicesHistory = context.Invoices.TemporalAll().ToList();  // invoicesHistory.Count =5
 var count = context.Invoices.TemporalAll().ToList().Count;   // count = 5 
     /*
     * If the records were not updated, the historical table should not retrieve  records,
     * you would expect the same behavior as SQL Server. 
     */

stack traces

   at System.Environment.get_StackTrace()\r\n   at MyForms.Form1.button1_Click(Object sender, EventArgs e) in C:\\Users\\PHILIPS.JESUSMENDOZA\\source\\repos\\MyForms\\Form1.cs:line 71\r\n   at System.Windows.Forms.Control.OnClick(EventArgs e)\r\n   at System.Windows.Forms.Button.OnClick(EventArgs e)\r\n   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)\r\n   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)\r\n   at System.Windows.Forms.Control.WndProc(Message& m)\r\n   at System.Windows.Forms.ButtonBase.WndProc(Message& m)\r\n   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)\r\n   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)\r\n   at Interop.User32.DispatchMessageW(MSG& msg)\r\n   at Interop.User32.DispatchMessageW(MSG& msg)\r\n   at System.Windows.Forms.Application.ComponentManager.Interop.Mso.IMsoComponentManager.FPushMessageLoop(UIntPtr dwComponentID, msoloop uReason, Void* pvLoopData)\r\n   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context)\r\n   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context)\r\n   at System.Windows.Forms.Application.Run(Form mainForm)\r\n   at MyForms.Program.Main() in C:\\Users\\PHILIPS.JESUSMENDOZA\\source\\repos\\MyForms\\Program.cs:line 14

Include provider and version information

EF Core version: EFC 6.0.1 Database provider: Microsoft.EntityFrameworkCore.SqlServer Target framework: .NET 6.0 Operating system: Edición Windows 10 Pro Versión 21H2 Se instaló el ‎08/‎12/‎2021 Compilación del SO 19044.1387 Experiencia Windows Feature Experience Pack 120.2212.3920.0

IDE: Microsoft Visual Studio Professional 2022 (64-bit) Version 17.0.3

[maumar]

TemporalAll maps to FOR SYSTEM_TIME ALL operation on sql server, which according to tsql documentation “Returns the union of rows that belong to the current and the history table.”. So we should adjust documentation to reflect that. But should consider providing a (convenient) way to query the history table directly given the discrepancy between ALL and history table shown in this scenario. For now you can use FromSql - make sure to use NoTracking

[ajcvickers]

@mendozagit

1-Could use normal properties (not shadow properties).

This is tracked by #26463.

2-Could the properties PeriodEnd and PeriodStart be nullable (for semantics) 3-There could be a simple and transparent way to query historical data,

The EF Core implementation aligns with the way this is implement in SQL Server. See https://docs.microsoft.com/en-us/sql/relational-databases/tables/temporal-tables?view=sql-server-ver15. The way the columns and queries are handled matches how temporal tables are implemented by SQL Server. I don’t think it makes sense for EF to do something different here; that would both be confusing, and would create mapping issues when attempting to go from EF to SQL Server.