查询查找可能的应该是外​​键的列？

Question

我正在寻找一个查询来帮助清理旧数据库，它没有多少关系。我并不需要它是完美的，只是为了帮助指导我开始清理并开始执行数据完整性。

我假设所有的表都具有正确的主键，并且尚未关联的表中的列具有相同的名称。

从理论上说，我可以有三个表，一个具有复合键（我也不会选择来设计这样的数据库，但在它的清理很有限的，这些类型的复合/主/外键是常见的）：

Case.CaseId（PK）
Workstep.WorkstepId（PK）
Workstep.CaseId（PK，FK）
WorkQueue.CaseId（不涉及Case.CaseId但应该是）

我希望能够做的是运行一个查询，并拿出结果，让我索姆ething如表名，列名，那是没有关系的，但应该是，该表的外键如：

表名，列名，应与PRIMARY KEY
工作队列，CaseId，Case.CaseId

请参阅下面我正在使用的SQL，但它返回任何主键，即使是既是主键也是外键的一部分。使用而不是返回1行再次我的例子，下面的SQL，我得到2：

表名，列名，应与PRIMARY KEY
工作队列，CaseId，Workstep.CaseId（我不希望这行，因为它也涉及到“真正的”主键，Case.CaseId）
工作队列，CaseId，Case.CaseId

SELECT 
    SubqueryAllPotentialForeignKeys.TABLE_NAME 
    ,SubqueryAllPotentialForeignKeys.COLUMN_NAME 
    ,(PrimaryKeys.TABLE_NAME + '.' + PrimaryKeys.COLUMN_NAME) as 'Possible Primary Key' 

--all potential foreign keys (column name matches another column name but there is no reference from this column anywhere else) 
FROM 
    ( 
    SELECT 
     INFORMATION_SCHEMA.COLUMNS.TABLE_NAME 
     ,INFORMATION_SCHEMA.COLUMNS.COLUMN_NAME 
    FROM 
     INFORMATION_SCHEMA.COLUMNS 
    WHERE 
     --only get columns that are in multiple tables 
     INFORMATION_SCHEMA.COLUMNS.COLUMN_NAME IN 
     (
      SELECT COLUMN_NAME FROM 
       (SELECT COLUMN_NAME, COUNT(COLUMN_NAME) AS ColNameCount FROM INFORMATION_SCHEMA.COLUMNS GROUP BY COLUMN_NAME) AS SubQueryColumns 
      WHERE ColNameCount > 1 
     ) 

     --only get the table.column if not part of a foreign or primary key 
     EXCEPT 
     (
      SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE 
     ) 

    ) AS SubqueryAllPotentialForeignKeys 

LEFT JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS PrimaryKeys ON 
    SubqueryAllPotentialForeignKeys.COLUMN_NAME = PrimaryKeys.COLUMN_NAME 

--when finding possible keys for our columns that don't have references, limit to primary keys 
WHERE 
    PrimaryKeys.CONSTRAINT_NAME LIKE '%PK_%' 

ORDER BY TABLE_NAME, COLUMN_NAME 

Answer 1

这可能不是世界上最美丽的东西，但工作得很好织补：

SELECT * FROM 
(
    SELECT 
     SubqueryAllPotentialForeignKeys.TABLE_NAME 
     ,SubqueryAllPotentialForeignKeys.COLUMN_NAME 
     ,(PrimaryKeys.TABLE_NAME + '.' + PrimaryKeys.COLUMN_NAME) as 'Possible Primary Key' 

    --all potential foreign keys (column name matches another column name but there is no reference from this column anywhere else) 
    FROM 
     ( 
     SELECT 
      INFORMATION_SCHEMA.COLUMNS.TABLE_NAME 
      ,INFORMATION_SCHEMA.COLUMNS.COLUMN_NAME 
     FROM 
      INFORMATION_SCHEMA.COLUMNS 
     WHERE 
      --only get columns that are in multiple tables 
      INFORMATION_SCHEMA.COLUMNS.COLUMN_NAME IN 
      (
       SELECT COLUMN_NAME FROM 
        (SELECT COLUMN_NAME, COUNT(COLUMN_NAME) AS ColNameCount FROM INFORMATION_SCHEMA.COLUMNS GROUP BY COLUMN_NAME) AS SubQueryColumns 
       WHERE ColNameCount > 1 
      ) 

      --only get the table.column if not part of a foreign or primary key 
      EXCEPT 
      (
       SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE 
      ) 

     ) AS SubqueryAllPotentialForeignKeys 

    LEFT JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS PrimaryKeys ON 
     SubqueryAllPotentialForeignKeys.COLUMN_NAME = PrimaryKeys.COLUMN_NAME 

    --when finding possible keys for our columns that don't have references, limit to primary keys 
    WHERE 
     PrimaryKeys.CONSTRAINT_NAME LIKE '%PK_%' 
) AS Subquery 

--exclude all keys that are primary but also foreign 
WHERE [Possible Primary Key] NOT IN 
    (
     SELECT (TABLE_NAME + '.' + COLUMN_NAME) 
     FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE 
     WHERE CONSTRAINT_NAME LIKE 'FK_%' 
    ) 

ORDER BY TABLE_NAME, COLUMN_NAME