Do temporal tables in SQL Server 2017 support foreign keys?

Question

If I try to add a foreign key to a temporal table in Visual Studio, it can't resolve the reference to the primary table for the key. This happens whether that table is also a temporal table or is not a temporal table.

The docs say you cannot have foreign keys in the history table for a temporal table... but they don't say you can't have them in the temporal table itself.

Is it possible ?

CREATE TABLE [Doc].[Document]
(
    [Id] INT NOT NULL PRIMARY KEY IDENTITY,
    [SysStart] DATETIME2 (7) GENERATED ALWAYS AS ROW START NOT NULL DEFAULT CAST('1900-1-1 00:00:00.0000000' AS datetime2),
    [SysEnd] DATETIME2 (7) GENERATED ALWAYS AS ROW END NOT NULL DEFAULT CAST('9999-12-31 12:59:59.9999999' AS datetime2), 
    [Name] NVARCHAR(250) NOT NULL, 
    [TypeId] INT NOT NULL, 
    [InActive] BIT NOT NULL DEFAULT 0, 
    [UpsertedBy] NVARCHAR(100) NOT NULL, 
    [DateAndTime] DATE NOT NULL DEFAULT getdate(), 

    CONSTRAINT [FK_Document_ToTable] 
        FOREIGN KEY ([TypeId]) **REFERENCES [Type]([Id])**, 

    PERIOD FOR SYSTEM_TIME ([SysStart], [SysEnd])
)
WITH (SYSTEM_VERSIONING = ON(HISTORY_TABLE=[Doc].[Document_HISTORY], DATA_CONSISTENCY_CHECK=ON))

Answer 1

Yes it's perfectly possible.

The below works fine

CREATE TABLE Foo(FooId INT PRIMARY KEY);


CREATE TABLE Bar
(
    [Id] INT NOT NULL PRIMARY KEY IDENTITY,
    FooId INT REFERENCES Foo, /*Works fine*/
    [SysStart] DATETIME2 (7) GENERATED ALWAYS AS ROW START NOT NULL DEFAULT CAST('1900-1-1 00:00:00.0000000' AS datetime2),
    [SysEnd] DATETIME2 (7) GENERATED ALWAYS AS ROW END NOT NULL DEFAULT CAST('9999-12-31 12:59:59.9999999' AS datetime2), 
    PERIOD FOR SYSTEM_TIME ([SysStart], [SysEnd])
)
WITH (SYSTEM_VERSIONING = ON)