在LINQ to SQL生成的SQL中,<column>为NULL vs<column>=NULL

var result = dataContext.Inventory
 .SingleOrDefault(x => (x.part_id == model.Part.id &&
                        x.location_id == transaction.to_location_id &&
                        x.bin_id == transaction.to_bin_id &&
                        x.project_id == transaction.project_id &&
                        x.expiration_date == inventoryToTransfer.expiration_date));

null . 我知道记录存在,但是生成的SQL(如果打开SQL日志记录)是

SELECT [t0].[id], [t0].[part_id], etc...
FROM [dbo].[Inventory] AS [t0]
INNER JOIN [dbo].[Parts] AS [t1] ON [t1].[id] = [t0].[part_id]
WHERE ([t0].[part_id] = @p0) AND (([t0].[location_id]) = @p1) AND ([t0].[bin_id] = @p2) AND
([t0].[project_id] = @p3) AND ([t0].[expiration_date] = @p4)
-- @p0: Input BigInt (Size = 0; Prec = 0; Scale = 0) [5197]
-- @p1: Input BigInt (Size = 0; Prec = 0; Scale = 0) [57]
-- @p2: Input BigInt (Size = 0; Prec = 0; Scale = 0) [71]
-- @p3: Input BigInt (Size = 0; Prec = 0; Scale = 0) [Null]
-- @p4: Input DateTime (Size = 0; Prec = 0; Scale = 0) [Null]

实际上,它将不返回任何内容,因为比较=NULL将不返回任何匹配项。我在想的是,这将生成一个空值(这非常有效)。这样地。。。

...
([t0].[project_id] IS NULL) AND ([t0].[expiration_date] IS NULL)

我知道,我知道。。。我不应该用空值来定义唯一性,但是有办法解决这个问题吗?