从扩展属性(SQL Server)获取元数据

Question

我正在构建一个数据字典，并试图从扩展属性中获取一些信息。

我有一个脚本来添加扩展属性(按预期工作(。

EXEC sys.sp_addextendedproperty 
@name=N'MS_Description', 
@value=N'This column stores the bla bla bla.' ,
@level0type=N'SCHEMA', 
@level0name=N'dbo', --Schema Name
@level1type=N'TABLE', 
@level1name=N'my_super_crazy_table',--Table Name 
@level2type=N'COLUMN', 
@level2name=N'my_super_crazy_column'--Column Name
GO

现在，我希望在理想的情况下能够看到这些内容是何时创建/更新的(如果我能看到哪个用户的话，那将是额外的奖励——suser_sname()(

---

我对数据字典的最终查询如下：

SELECT tbl.name as [table_name],
clmns.name as [column_name],
exprop.value as [column_description]
-- exprop.*
FROM sys.tables AS tbl
INNER JOIN sys.all_columns AS clmns ON clmns.object_id=tbl.object_id
LEFT OUTER JOIN sys.extended_properties exprop ON exprop.major_id = clmns.object_id AND exprop.minor_id = clmns.column_id
WHERE (tbl.name IN ('my_super_crazy_table') and exprop.class = 1) 

输出：

table_name     |     column_name     |       column_description
my_super_crazy_table|my_super_crazy_column|This column stores the bla bla bla.

---

是否有其他sys表格可以为我提供所需信息？感谢

Answer 1

SQL Server当前不存储任何关于何时添加或更新扩展属性或由谁添加或更新的信息。

您可能最终想要实现更多的逻辑。这是我目前最好的剧本。

https://www.csvreader.com/posts/data_dictionary.sql

SELECT
d.[primary key],
d.[foreign key],
CASE
WHEN LEN(d.[column]) = 0 THEN d.[table]
ELSE ''
END AS [table],
d.[column],
CAST(d.[description] AS VARCHAR(MAX)) AS [description],
d.[data type],
d.nullable,
d.[identity],
d.[default]
FROM
(
SELECT
'' AS [primary key],
'' AS [foreign key],
s.[name] AS [schema],
CASE
WHEN s.[name] = 'dbo' THEN t.[name]
ELSE s.[name] + '.' + t.[name]
END AS [table],
'' AS [column],
ISNULL(RTRIM(CAST(ep.[value] AS NVARCHAR(4000))), '') AS [description],
'' AS [data type],
'' AS nullable,
'' AS [identity],
'' AS [default],
NULL AS column_id
FROM
sys.tables t
INNER JOIN sys.schemas s ON
s.[schema_id] = t.[schema_id]
-- get description of table, if available
LEFT OUTER JOIN sys.extended_properties ep ON
ep.major_id = t.[object_id] AND
ep.minor_id = 0 AND
ep.name = 'MS_Description' AND
ep.class = 1
WHERE
t.is_ms_shipped = 0 AND
NOT EXISTS
(
SELECT *
FROM
sys.extended_properties ms
WHERE
ms.major_id = t.[object_id] AND
ms.minor_id = 0 AND
ms.class = 1 AND
ms.[name] = 'microsoft_database_tools_support'
)
UNION ALL
SELECT
CASE
WHEN pk.column_id IS NOT NULL THEN 'PK'
ELSE ''
END AS [primary key],
CASE
WHEN fk.primary_table IS NOT NULL
THEN fk.primary_table + '.' + fk.primary_column
ELSE ''
END AS [foreign key],
s.[name] AS [schema],
CASE
WHEN s.[name] = 'dbo' THEN t.[name]
ELSE s.[name] + '.' + t.[name]
END AS [table],
c.[name] AS [column],
ISNULL(RTRIM(CAST(ep.[value] AS NVARCHAR(4000))), '') AS [description],
CASE
WHEN uty.[name] IS NOT NULL THEN uty.[name]
ELSE ''
END +
CASE
WHEN uty.[name] IS NOT NULL AND sty.[name] IS NOT NULL THEN '('
ELSE ''
END +
CASE
WHEN sty.[name] IS NOT NULL THEN sty.[name]
ELSE ''
END +
CASE
WHEN sty.[name] IN ('char', 'nchar', 'varchar', 'nvarchar', 'binary', 'varbinary')
THEN '(' + 
CASE
WHEN c.max_length = -1 THEN 'max'
ELSE 
CASE
WHEN sty.[name] IN ('nchar', 'nvarchar')
THEN CAST(c.max_length / 2 AS VARCHAR(MAX))
ELSE
CAST(c.max_length AS VARCHAR(MAX))
END
END
+ ')'
WHEN sty.[name] IN ('numeric', 'decimal')
THEN '(' + 
CAST(c.precision AS VARCHAR(MAX)) + ', ' + CAST(c.scale AS VARCHAR(MAX))
+ ')'
ELSE
''
END +
CASE
WHEN uty.[name] IS NOT NULL AND sty.[name] IS NOT NULL THEN ')'
ELSE ''
END AS [data type],
CASE
WHEN c.is_nullable = 1 THEN 'Y'
ELSE ''
END AS nullable,
CASE
WHEN c.is_identity = 1 THEN 'Y'
ELSE ''
END AS [identity],
ISNULL(dc.[definition], '') AS [default],
c.column_id
FROM
sys.columns c
INNER JOIN sys.tables t ON
t.[object_id] = c.[object_id]
INNER JOIN sys.schemas s ON
s.[schema_id] = t.[schema_id]
-- get name of user data type
LEFT OUTER JOIN sys.types uty ON
uty.system_type_id = c.system_type_id AND
uty.user_type_id = c.user_type_id AND
c.user_type_id <> c.system_type_id
-- get name of system data type
LEFT OUTER JOIN sys.types sty ON
sty.system_type_id = c.system_type_id AND
sty.user_type_id = c.system_type_id
-- get description of column, if available
LEFT OUTER JOIN sys.extended_properties ep ON
ep.major_id = t.[object_id] AND
ep.minor_id = c.column_id AND
ep.[name] = 'MS_Description' AND
ep.[class] = 1
-- get default's code text
LEFT OUTER JOIN sys.default_constraints dc ON
dc.parent_object_id = t.[object_id] AND
dc.parent_column_id = c.column_id
-- check for inclusion in primary key
LEFT OUTER JOIN
(
SELECT
ic.column_id,
i.[object_id]
FROM
sys.indexes i
INNER JOIN sys.index_columns ic ON
ic.index_id = i.index_id AND
ic.[object_id] = i.[object_id]
WHERE
i.is_primary_key = 1
) pk ON
pk.column_id = c.column_id AND
pk.[object_id] = t.[object_id]
-- check for inclusion in foreign key
LEFT OUTER JOIN
(
SELECT
CASE
WHEN s.[name] = 'dbo' THEN pk.[name]
ELSE s.[name] + '.' + pk.[name]
END AS primary_table,
pkc.[name] as primary_column,
fkc.parent_object_id,
fkc.parent_column_id
FROM
sys.foreign_keys fk
INNER JOIN sys.tables pk ON
fk.referenced_object_id = pk.[object_id]
INNER JOIN sys.schemas s ON
s.[schema_id] = pk.[schema_id]
INNER JOIN sys.foreign_key_columns fkc ON
fkc.constraint_object_id = fk.[object_id] AND
fkc.referenced_object_id = pk.[object_id]
INNER JOIN sys.columns pkc ON
pkc.[object_id] = pk.[object_id] AND
pkc.column_id = fkc.referenced_column_id
) fk ON
fk.parent_object_id = t.[object_id] AND
fk.parent_column_id = c.column_id
WHERE
t.is_ms_shipped = 0 AND
NOT EXISTS
(
SELECT *
FROM
sys.extended_properties ms
WHERE
ms.major_id = t.[object_id] AND
ms.minor_id = 0 AND
ms.class = 1 AND
ms.[name] = 'microsoft_database_tools_support'
)
) d
ORDER BY
d.[schema],
d.[table],
d.column_id;