更改 SQL Server 中的主键列

Change primary key column in SQL Server

提问by ckbhodge

UPDATE

更新

Here are the constraints as a result of the query

以下是查询结果的约束

SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME = 'history'

CONSTRAINT_NAME   COLUMN_NAME  ORDINAL_POSITION
PK_history        userKey       1
PK_history        name          2

Here is the result of the query

这是查询的结果

SELECT * 
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
WHERE TABLE_NAME = 'history'

CONSTRAINT_NAME   CONSTRAINT_TYPE  IS_DEFERRABLE  INITIALLY_DEFERRED
PK_history        PRIMARY KEY      NO             NO

END UPDATE

结束更新

My host provides an interface to my SQL Server DB via ASP.NET Enterprise Manager.

我的主机通过 ASP.NET Enterprise Manager 为我的 SQL Server DB 提供了一个接口。

I have 3 columns in my historytable:

我的表中有 3 列history：

• userId(key, int, NULL not allowed)
• name(key, string, NULL not allowed)
• id(not key, int, NULL allowed)

• userId(key, int, NULL 不允许)
• name(key, string, NULL 不允许)
• id（不允许 key、int、NULL）

I want to make the id column the only key.

我想让 id 列成为唯一的键。

To do that, I believe I need to:

为此，我相信我需要：

1. Make sure there are no NULLs in that column for any row
2. Set the column to not allow NULLs
3. Add the column as a primary key
4. Remove the other 2 columns as keys

1. 确保该列中的任何行都没有 NULL
2. 将列设置为不允许 NULL
3. 将该列添加为主键
4. 删除其他 2 列作为键

However, when I use the UI provided, it never works. Sometimes it'll just look like it tries to do something but it never changes when I refresh the view of the columns. It occasionally creates a temp table that looks like it tried to do some of the operation, but that never gets copied/overwrites the original table that I'm trying to change.

但是，当我使用提供的 UI 时，它永远无法工作。有时它看起来就像试图做某事，但当我刷新列的视图时它永远不会改变。它偶尔会创建一个临时表，看起来它试图执行某些操作，但它永远不会被复制/覆盖我试图更改的原始表。

When I try using a query, the changes don't show up either. Here are the queries I think I need:

当我尝试使用查询时，更改也不会显示。以下是我认为我需要的查询：

    SELECT * from history WHERE id is NULL     <---- This shows 0 results

    ALTER TABLE history
    ALTER COLUMN id int NOT NULL

    ALTER TABLE history ADD PRIMARY KEY (id)

    ALTER TABLE history
    DROP CONSTRAINT userId
    DROP CONSTRAINT name
    GO

I've only gotten to the attempt to disallow NULLs and to add the primary key for the id column. It doesn't seem to work. Can someone point me in the right direction? Thanks!

我只是尝试禁止 NULL 并为 id 列添加主键。它似乎不起作用。有人可以指出我正确的方向吗？谢谢！

回答by competent_tech

Assuming that your current primary key constraint is called pk_history, you can replace the following lines:

假设您当前的主键约束称为 pk_history，您可以替换以下几行：

ALTER TABLE history ADD PRIMARY KEY (id)

ALTER TABLE history
DROP CONSTRAINT userId
DROP CONSTRAINT name

with these:

用这些：

ALTER TABLE history DROP CONSTRAINT pk_history

ALTER TABLE history ADD CONSTRAINT pk_history PRIMARY KEY (id)

If you don't know what the name of the PK is, you can find it with the following query:

如果您不知道 PK 的名称是什么，可以使用以下查询找到它：

SELECT * 
  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
 WHERE TABLE_NAME = 'history'

回答by Stefan Steiger

Necromancing.
It looks you have just as good a schema to work with as me... Here is how to do it correctly:

死灵法术。
看起来你有一个和我一样好的模式......这里是如何正确地做到这一点：

In this example, the table name is dbo.T_SYS_Language_Forms, and the column name is LANG_UID

本例中，表名为dbo.T_SYS_Language_Forms，列名为LANG_UID

-- First, chech if the table exists...
IF 0 < (
    SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES 
    WHERE TABLE_TYPE = 'BASE TABLE'
    AND TABLE_SCHEMA = 'dbo'
    AND TABLE_NAME = 'T_SYS_Language_Forms'
)
BEGIN
    -- Check for NULL values in the primary-key column
    IF 0 = (SELECT COUNT(*) FROM T_SYS_Language_Forms WHERE LANG_UID IS NULL)
    BEGIN
        ALTER TABLE T_SYS_Language_Forms ALTER COLUMN LANG_UID uniqueidentifier NOT NULL 

        -- No, don't drop, FK references might already exist...
        -- Drop PK if exists 
        -- ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT pk_constraint_name 
        --DECLARE @pkDropCommand nvarchar(1000) 
        --SET @pkDropCommand = N'ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT ' + QUOTENAME((SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
        --WHERE CONSTRAINT_TYPE = 'PRIMARY KEY' 
        --AND TABLE_SCHEMA = 'dbo' 
        --AND TABLE_NAME = 'T_SYS_Language_Forms' 
        ----AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms' 
        --))
        ---- PRINT @pkDropCommand 
        --EXECUTE(@pkDropCommand) 

        -- Instead do
        -- EXEC sp_rename 'dbo.T_SYS_Language_Forms.PK_T_SYS_Language_Forms1234565', 'PK_T_SYS_Language_Forms';


        -- Check if they keys are unique (it is very possible they might not be) 
        IF 1 >= (SELECT TOP 1 COUNT(*) AS cnt FROM T_SYS_Language_Forms GROUP BY LANG_UID ORDER BY cnt DESC)
        BEGIN

            -- If no Primary key for this table
            IF 0 =  
            (
                SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
                WHERE CONSTRAINT_TYPE = 'PRIMARY KEY' 
                AND TABLE_SCHEMA = 'dbo' 
                AND TABLE_NAME = 'T_SYS_Language_Forms' 
                -- AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms' 
            )
                ALTER TABLE T_SYS_Language_Forms ADD CONSTRAINT PK_T_SYS_Language_Forms PRIMARY KEY CLUSTERED (LANG_UID ASC)
            ;

            -- Adding foreign key
            IF 0 = (SELECT COUNT(*) FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS WHERE CONSTRAINT_NAME = 'FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms') 
                ALTER TABLE T_ZO_SYS_Language_Forms WITH NOCHECK ADD CONSTRAINT FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms FOREIGN KEY(ZOLANG_LANG_UID) REFERENCES T_SYS_Language_Forms(LANG_UID); 
        END -- End uniqueness check
        ELSE
            PRINT 'FSCK, this column has duplicate keys, and can thus not be changed to primary key...' 
    END -- End NULL check
    ELSE
        PRINT 'FSCK, need to figure out how to update NULL value(s)...' 
END