我编写了一个查询来查找主键 - 数据库中所有表之间的外键关系。仅当我们在物理上存在外键时才有效。
请运行此查询以清楚地了解我的问题。
WITH cte
AS
(
SELECT
fk.create_date
, fk.modify_date
, fkc.constraint_object_id AS ConstraintId
, OBJECT_NAME(fkc.constraint_object_id) AS ConstraintName
--, fkc.referenced_object_id AS PrimaryKeyTableId
, OBJECT_NAME(fkc.referenced_object_id) AS PrimaryKeyTableName
--, fkc.referenced_column_id AS PrimaryKeyColumnId
, rc.name AS PrimaryKeyColumnName
--, fk.parent_object_id AS ForeignKeyTableId
, OBJECT_NAME(fk.parent_object_id) AS ForeignKeyTableName
--, fkc.parent_column_id AS ForeignKeyColumnId
, lc.name AS ForeignKeyColumnName
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns rc
ON rc.OBJECT_ID = fkc.referenced_object_id
AND fkc.referenced_column_id = rc.column_id
INNER JOIN sys.foreign_keys fk
ON fk.OBJECT_ID = fkc.constraint_object_id
INNER JOIN sys.columns lc
ON lc.OBJECT_ID = fk.parent_object_id
AND fkc.parent_column_id = lc.column_id
)
, cte2(create_date, modify_date, ConstraintName
, PrimaryKeyTableName, PrimaryKeyColumnName
, ForeignKeyTableName, ForeignKeyColumnName
, Hops, path ) AS
(
SELECT
create_date, modify_date, ConstraintName
, PrimaryKeyTableName, PrimaryKeyColumnName
, ForeignKeyTableName, ForeignKeyColumnName
, 1 , CAST(QUOTENAME(PrimaryKeyTableName + '.' + PrimaryKeyColumnName) AS VARCHAR(4000))
FROM cte
UNION ALL
SELECT
cte.create_date, cte.modify_date, cte.ConstraintName
, cte.PrimaryKeyTableName, cte.PrimaryKeyColumnName
, cte.ForeignKeyTableName, cte.ForeignKeyColumnName
, cte2.Hops +1, CAST(cte2.path + '-> ' +QUOTENAME(cte.PrimaryKeyTableName+ '.' + cte.PrimaryKeyColumnName) AS VARCHAR(4000))
FROM cte2 INNER JOIN cte ON cte2.ForeignKeyTableName = cte.PrimaryKeyTableName
AND cte2.ForeignKeyColumnName != cte.PrimaryKeyColumnName
)
SELECT
ConstraintName
, PrimaryKeyTableName, PrimaryKeyColumnName
, ForeignKeyTableName, ForeignKeyColumnName
, Hops, path + '-> ' + QUOTENAME(ForeignKeyTableName + '.' + ForeignKeyColumnName) AS Path
FROM cte2
除非我们在数据库中存在复合主键,否则上面的查询工作顺利。
假设我有一张桌子
因此,考虑到复合主键场景,当前查询不会生成路径。
我想生成类似的路径。
[Method.MethodId] - > [ParameterMethodMap.MethodId,ParameterMethodMap.ParameterId] - > [Test.TestId] - > [Sample.SampleId]
这是某种方式我想合并复合主键。我怎么能这样做?
答案 0 :(得分:0)
通常,因为您不能在CTE的递归部分中使用聚合函数,所以应该将列连接部分移动到另一个CTE。你将拥有:
;
WITH CTE_FKCols
AS (
SELECT FK.NAME
,'[' + STUFF((
SELECT ','
,object_name(Col.object_id) + '.' + col.NAME
FROM sys.foreign_key_columns C
INNER JOIN sys.columns Col ON Col.object_id = c.referenced_object_id
AND col.column_id = c.referenced_column_id
WHERE C.constraint_object_id = FK.object_id
FOR XML PATH('')
), 1, 1, '') + ']' Cols
FROM sys.foreign_keys FK
)
,CTE
AS (
SELECT fk.create_date
,fk.modify_date
,fkc.constraint_object_id AS ConstraintId
,OBJECT_NAME(fkc.constraint_object_id) AS ConstraintName
--, fkc.referenced_object_id AS PrimaryKeyTableId
,OBJECT_NAME(fkc.referenced_object_id) AS PrimaryKeyTableName
--, fkc.referenced_column_id AS PrimaryKeyColumnId
,OBJECT_NAME(fk.parent_object_id) AS ForeignKeyTableName
FROM sys.foreign_key_columns fkc
INNER JOIN sys.foreign_keys fk ON fk.OBJECT_ID = fkc.constraint_object_id
)
,cte2 (
create_date
,modify_date
,ConstraintName
,PrimaryKeyTableName
,ForeignKeyTableName
,Hops
,path
)
AS (
SELECT create_date
,modify_date
,ConstraintName
,PrimaryKeyTableName
,ForeignKeyTableName
,1
,CAST((
SELECT F.Cols
FROM CTE_FKCols F
WHERE F.NAME = cte.ConstraintName
) AS NVARCHAR(4000))
FROM cte
UNION ALL
SELECT cte.create_date
,cte.modify_date
,cte.ConstraintName
,cte.PrimaryKeyTableName
,cte.ForeignKeyTableName
,cte2.Hops + 1
,CAST((
cte2.path + CAST('-> ' AS NVARCHAR(4000)) + (
SELECT F.Cols
FROM CTE_FKCols F
WHERE F.NAME = cte.ConstraintName
)
) AS NVARCHAR(4000))
FROM cte2
INNER JOIN cte ON cte2.ForeignKeyTableName = cte.PrimaryKeyTableName
AND cte2.PrimaryKeyTableName != cte.PrimaryKeyTableName --Remove self-reference
)
SELECT *
FROM cte2