如何解决是否可以遍历我的SQL数据库中的每个表并查找其他行未使用的记录? PK / FK检查
我想编写一个SQL脚本,该脚本可以指出整个数据库中的哪些记录未被其他表用作引用。
例如,如果我有一个“ 评论”表,我想找出表中的哪些记录在用户中没有关系条目,帖子中的 nor ,但未按名称指定这些表格。 像这样:
'COLLECT ALL TABLES'
'LOOP OVER EACH ROW IN THIS TABLE'
'CHECK OTHER TABLES TO SEE IF THIS PARTICULAR PK_ID IS PRESENT AS A FOREIGN KEY'
'IF FOUND NOT FOUND'
'DELETE THIS ROW FROM THIS TABLE'
我知道如何做“如果没有找到”和“删除”部分,但是我在努力寻找前三个步骤。 欢迎任何想法和/或有用的提示或链接。 我很高兴在完成这篇文章后分享我的脚本作为对此文章的评论,因为我认为许多SQL开发人员都可以使用它。
解决方法
我想出自己编写脚本的地方,这里就是(使用Dynamic SQL)
我有185个表和〜190.000个Description条目,执行此脚本后最终得到了〜15.000个Description行。 (问题是,在更改对象的描述时创建了新的描述,而不是对其进行更新。在代码中修复此错误后,我进入了数据库)。该脚本花费了大约3个小时来完成。
USE [YOUR_DATABASE]
PRINT 'BEGIN SCRIPT'
-- put all the tables in your database in a table (where we will perform a cursor on)
SELECT TABLE_NAME INTO ALL_TABLES
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE' AND TABLE_CATALOG='YOUR_DATABASE'
-- delete non relevant entities in ALL_TABLES table
delete from ALL_TABLES where TABLE_NAME = 'ALL_TABLES' -- delete the 'all_tables' table
delete from ALL_TABLES where TABLE_NAME = 'DESCRIPTION' -- your to-check table
-- hide rowcounts
set nocount on
-- Variables to use in the cursors
DECLARE
@tableName NVARCHAR(MAX),@descriptionId INT,@descriptionInUse BIT;
-- cursor to get all the entities from ALL_TABLES
DECLARE cursor_allTables CURSOR
FOR SELECT
TABLE_NAME
FROM
dbo.ALL_TABLES;
-- cursor to get all the entities out of your to-check table ( mine was Description )
DECLARE cursor_descriptionCleanUp CURSOR
FOR SELECT
Id
FROM
dbo.Description;
-- start iterating over descriptions
OPEN cursor_descriptionCleanUp;
FETCH NEXT FROM cursor_descriptionCleanUp INTO
@descriptionId;
WHILE @@FETCH_STATUS = 0
BEGIN
-- set BIT to check if description is in use
set @descriptionInUse = 0;
-- start iterating over ALL_TABLE rows
OPEN cursor_allTables;
FETCH NEXT FROM cursor_allTables INTO
@tableName;
WHILE @@FETCH_STATUS = 0 AND @descriptionInUse= 0
BEGIN
-- check if this table has a DescriptionId
IF COL_LENGTH('dbo.'+@tableName,'DescriptionId') IS NOT NULL
BEGIN
-- check the table
DECLARE @sql as nvarchar(MAX);
DECLARE @rowCount as int;
SET @sql = 'SELECT DescriptionId FROM '+ @tableName+' where DescriptionId = '+ CAST(@descriptionId as nvarchar(MAX))
EXEC (@sql)
SELECT @rowCount = @@ROWCOUNT;
-- If EXEC (@sql) returned more than 0 rows,this Description row is in use in a table -> mark it as used
IF @rowCount > 0
BEGIN
set @descriptionInUse= 1;
END
END
FETCH NEXT FROM cursor_allTables INTO
@tableName;
END;
CLOSE cursor_allTables;
--if description row is not in use -> delete this row
IF @descriptionInUse = 0
BEGIN
DELETE FROM Description where Id = @descriptionId;
PRINT 'DELETE DESCRIPTION WITH ID: ' + CAST(@descriptionId as nvarchar(MAX))
PRINT'----------------------------------------------'
END
-- fetch next Description Id from Descriptions
FETCH NEXT FROM cursor_descriptionCleanUp INTO
@descriptionId;
END;
CLOSE cursor_descriptionCleanUp;
-- clean up
DEALLOCATE cursor_descriptionCleanUp;
DEALLOCATE cursor_allTables;
drop table ALL_TABLES
-- set nocount back to on
set nocount off
我希望它可以帮助其他人:-)
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