创建在 SQL 服务器分区视图中工作的不确定 CHECK CONSTRAINT

Question

Context

A SQL partitioned view reads tables like any other view. However, what makes them special is that they allow me to write to the underlying tables through when a portioning key column is indicated by using a CHECK CONSTRAINT on the underlying tables.

• Read more in the Online Docs .

An Example

For example, here a CHECK CONSTRAINT validates the [Year] column value is always 2022 . The value of 2022 in the CHECK is a hard coded (deterministic) value. During a SELECT operation, the view ignores the CHECK but during an INSERT operation, the CHECK instructs the view to which table it should insert the record(s).

CREATE TABLE Part2022 
(
    Id UNIQUEIDENTIFIER UNIQUE CLUSTERED
  , Year INT CONSTRAINT req2022 CHECK (Year = 2022) 
    PRIMARY KEY NONCLUSTERED (Id, Year)
);

Using this approach, a partitioning view would look like this:

CREATE VIEW Parts AS
            SELECT * FROM Part2022
  UNION ALL SELECT * FROM Part2021
  UNION ALL SELECT * FROM Part2020

This works just fine.

The question

I understand the issue, but I wonder if some clever data engineer out there has figured a workaround that would enable a different approach - something similar to this:

CREATE TABLE PartCurrent
(
    Id UNIQUEIDENTIFIER UNIQUE CLUSTERED
  , Year INT CONSTRAINT reqCurrent CHECK (Year = YEAR(GETUTCDATE())) 
    PRIMARY KEY NONCLUSTERED (Id, Year)
);

Of course, this does not work. Though the CHECK CONSTRAINT can be applied to the table without issue, including this table in a partitioned view now results in:

Msg 4436, Level 16, State 12, Line 53 view is not updatable because a partitioning column was not found.

Q: Is there a way to use an indeterminate CHECK CONSTRAINT with a partitioned view?

PS: I know what partitioned tables are and when to use them in a model. In this case, though, they do not meet the requirements. As a result, I am asking about partitioned views. Thx.

Answer 1

Answer: Though a check constraint condition can be dynamic in a table, if that table is in a partition view, checks on partition key columns must be hardcoded. This is by design.

• Read the Docs .

That is to say, you must do something like this:

CREATE TABLE Part2022 
(
    Id UNIQUEIDENTIFIER UNIQUE CLUSTERED
  , Year INT CONSTRAINT req2022 CHECK (Year = 2022) 
    PRIMARY KEY NONCLUSTERED (Id, Year)
);

You cannot do something like this:

CREATE TABLE Part2022 
(
    Id UNIQUEIDENTIFIER UNIQUE CLUSTERED
  , Year INT CONSTRAINT req2022 CHECK (Year = YEAR(GETUTCDATE())) 
    PRIMARY KEY NONCLUSTERED (Id, Year)
);