SMO issue with default column values.

先在 SMO 中重現 CREATE TABLE 和 ALTER TABLE 的情況，然後追蹤產生 SQL 的 SMO 預設值指令碼路徑。將輸出與資料庫定義以及 DacFx ScriptComparison 的行為進行比較；當 10 或 0 等原始預設值能以一致的方式表示且沒有多餘的括號時，即表示完成。

Greetings. To reproduce. . .

Create the following table:

CREATE TABLE DefaultTest (
    [FlagValue] INT DEFAULT 10
)

Then, generate the SMO script. You will get:

CREATE TABLE [dbo].[DefaultTest] (
    [FlagValue] INT DEFAULT ((10)) NULL
);

This is odd, why has the 10 become ((10))? Syntax wise, 10 is OK.
The same happens if you create the table without the default, then add it with:

ALTER TABLE DefaultTest ADD DEFAULT 10 FOR [FlagValue]

What's interesting, is that if you use Azure Data Studio to edit the ((10)) default value in the UI back to 10 (maybe the UI isn't using SMO?), the SQL it generates displays as:

CREATE TABLE [dbo].[DefaultTest] (
    [FlagValue] INT DEFAULT 10 NULL
);

. . . which instantly becomes ((10)) again when you apply the change to the database.

Now, the engine always stores the constraints definition wrapped with ( and ).
I contend there is a bug in SMO -- if the value within parenthesis is a primitive (string, integer, etc), then it doesn't need parenthesis.

Why is this a problem? Currently writing code to compare schemas against two databases, and having to parse weird output from DacFx's ScriptComparison, which is complaining that default values of (0) sometimes become ((0)). Now, I can write an AST parser using ScriptDom, but isn't this an SMO error?

Basically, it means that SMO isn't generating a technically identical representation of the table.

Thanks!