SQL 服务器 :: 从数据库无约束地创建 ERD

Question

我有一个数据库，没有任何限制，没有PK或FK。

我正在尝试通过逆向工程找出表之间的联系。为此，我的方法是创建一个包含具有相同名称和数据类型的所有列的列表。所以我创建了这个查询：

SELECT schema_name(tab.schema_id) AS schema_name
    ,tab.name AS table_name
    ,col.name AS column_name
    ,t.name AS data_type
    ,SUM([Partitions].[rows]) AS [TotalRowCount]
    
FROM sys.tables AS tab
INNER JOIN sys.columns AS col ON tab.object_id = col.object_id
LEFT JOIN sys.types AS t ON col.user_type_id = t.user_type_id
JOIN sys.partitions AS [Partitions] ON tab.[object_id] = [Partitions].[object_id]
    AND [Partitions].index_id IN (
        0
        ,1
        )

GROUP BY schema_name(tab.schema_id)
    ,tab.name
    ,col.name
    ,t.name
    
ORDER BY col.name

结果我得到了这个：

schema_name	table_name	column_name	data_type	TotalRowCount
H513WEB	ALPRETAR	IDREVI	numeric	1439
H513WEB	ALPRETAR	IDREVN	numeric	1439
H513WEB	CPDOENP	IDRLPP	numeric	4156
H513WEB	ALPRETAR	IDRNG	numeric	1439
H513WEB	FAAFACP	IDROLDEBCOM	numeric	100541
H513WEB	FAAFACP_OLD	IDROLDEBCOM	numeric	1513
H513WEB	CACPTAP	IDROLE	numeric	22109
H513WEB	CARROLP	IDROLE	numeric	5
H513WEB	FAENTFP	IDROLE	numeric	26084
H513WEB	CACPTCP	IDRUBRIQUE	numeric	48
H513WEB	CACPTRP	IDRUBRIQUE	numeric	12942
H513WEB	CAIMDCP	IDRUBRIQUE	numeric	6637
H513WEB	CAIMGIP	IDRUBRIQUE	numeric	5
H513WEB	CAIMRSP	IDRUBRIQUE	numeric	40
H513WEB	CAOREXP	IDRUBRIQUE	numeric	5
H513WEB	CAPLARP	IDRUBRIQUE	numeric	3
H513WEB	CARERUP	IDRUBRIQUE	numeric	175
H513WEB	CARUBRP	IDRUBRIQUE	numeric	312

但我只想列出具有相同 column_name 和 data_type 的行，结果应如下所示：

schema_name	table_name	column_name	data_type	TotalRowCount
H513WEB	FAAFACP	IDROLDEBCOM	numeric	100541
H513WEB	FAAFACP_OLD	IDROLDEBCOM	numeric	1513
H513WEB	CACPTAP	IDROLE	numeric	22109
H513WEB	CARROLP	IDROLE	numeric	5
H513WEB	FAENTFP	IDROLE	numeric	26084
H513WEB	CACPTCP	IDRUBRIQUE	numeric	48
H513WEB	CACPTRP	IDRUBRIQUE	numeric	12942
H513WEB	CAIMDCP	IDRUBRIQUE	numeric	6637
H513WEB	CAIMGIP	IDRUBRIQUE	numeric	5
H513WEB	CAIMRSP	IDRUBRIQUE	numeric	40
H513WEB	CAOREXP	IDRUBRIQUE	numeric	5
H513WEB	CAPLARP	IDRUBRIQUE	numeric	3
H513WEB	CARERUP	IDRUBRIQUE	numeric	175
H513WEB	CARUBRP	IDRUBRIQUE	numeric	312

怎么做？

Answer 1

如果您要尝试识别 PK 和 FK 候选项，那么不仅需要匹配数据类型，还需要匹配长度、小数位数和精度。例如，varchar(10) 不能是 varchar(8) 的外键。实际上，名称根本不需要匹配，但如果不包含该名称，您最终会得到大量误报。

我已经猜到了你想要的东西，但我认为这可能是正确的。另一方面，（估计的）行数似乎根本没有必要，所以我从查询中删除了它：

WITH ColumnCount AS(
    SELECT s.name AS SchemaName,
           t.name AS TableName,
           c.name AS ColumnName,
           ct.[name] AS DataType,
           c.max_length,
           c.precision,
           c.scale,
           COUNT(c.column_id) OVER (PARTITION BY c.[name], ct.[name], c.max_length, c.precision, c.scale) AS Duplicates
    FROM sys.schemas s
         JOIN sys.tables t ON s.schema_id = t.schema_id
         JOIN sys.columns c ON t.object_id = c.object_id
         JOIN sys.types ct ON c.user_type_id = ct.user_type_id)
SELECT *
FROM ColumnCount CC
WHERE CC.Duplicates > 1
ORDER BY CC.ColumnName,
         CC.SchemaName,
         CC.TableName;

SQL 服务器 :: 从数据库无约束地创建 ERD

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