如何将自定义属性添加到 SQL 连接字符串?

2021-12-07 00:00:00 function tsql sql-server extended-properties

我想在 SqlServer 连接字符串中添加一些自定义属性，如下所示:

I want to add some custom attributes in SqlServer connection string, something like this:

Integrated Security=SSPI;Extended Properties="SomeAttr=SomeValue";Persist Security Info=False;Initial Catalog=DB;Data Source=SERVER

然后在 sql 中获取该属性.例如 SELECT SOME_FUNCTION('SomeAttr')

And then get that attribute in sql. for example SELECT SOME_FUNCTION('SomeAttr')

推荐答案

没有通用的方法可以通过客户端 API 传递自定义连接字符串属性并使用 T-SQL 进行检索.不过，您有多种选择.以下是一些.

There is no generalized method to pass custom connection string attributes via Client APIs and retrieve using T-SQL. You have a number of alternatives, though. Below are a few.

方法 1:在连接字符串中使用 Application Name 关键字最多传递 128 个字符并使用 APP_NAME() T-SQL 函数检索:

Method 1: Use the Application Name keyword in the connection string to pass up to 128 characters and retrieve with the APP_NAME() T-SQL function:

Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=DB;Data Source=SERVER;Application Name="SomeAttr=SomeValue"

SELECT APP_NAME();

请注意，这限制为 128 个字符，您需要解析有效负载.此外，由于 ADO.NET 为每个不同的连接字符串创建了一个单独的连接池，请考虑实际上很少或没有数据库连接池.

Note that this is limited to 128 characters and you will need to parse the payload. Also, since ADO.NET creates a separate connection pool for each distinct connection string, consider there will effectively be little or no database connection pooling.

方法二:连接后执行SET CONTEXT_INFO并分配最多128个字节，可以用CONTEXT_INFO检索)T-SQL函数:

Method 2: Execute a SET CONTEXT_INFO after connect and assign up to 128 bytes that can be retreived with the CONTEXT_INFO) T-SQL function:

DECLARE @context_info varbinary(128) = CAST('SomeAttr=SomeValue' AS varbinary(128));
SET CONTEXT_INFO @context_info;

SELECT CAST(CONTEXT_INFO() AS varchar(128));

请注意，这限制为 128 个字节，您需要解析有效负载.

Note that this is limited to 128 bytes and you will need to parse the payload.

方法 3:在连接和插入可以通过 SELECT 查询检索的名称/值对后创建会话级临时表:

Method 3: Create a session-level temporary table after connect and insert name/value pairs that can be retrieved with a SELECT query:

CREATE TABLE #CustomSessionAttributes(
      AttributeName varchar(128) PRIMARY KEY
    , AttributeValue varchar(1000));
INSERT INTO #CustomSessionAttributes VALUES('SomeAttr', 'SomeValue');

SELECT AttributeValue 
FROM #CustomSessionAttributes 
WHERE AttributeName = 'SomeAttr';

注意可以根据需要增加属性值大小和类型，不需要解析.

Note that you can increase the attribute value size and type as needed, and no parsing is needed.

方法 4:创建一个以会话 ID 和属性名称为键的永久表，在连接后插入可以使用 SELECT 查询检索的名称/值对:

Method 4: Create a permanent table keyed by session id and attribute name, insert name/value pairs after connect that can be retrieved with a SELECT query:

CREATE TABLE dbo.CustomSessionAttributes(
      SessionID smallint
    , AttributeName varchar(128)
    , AttributeValue varchar(1000)
    , CONSTRAINT PK_CustomSessionAttributes PRIMARY KEY (SessionID, AttributeName)
    );
--clean up previous session
DELETE FROM dbo.CustomSessionAttributes WHERE SessionID = @@SPID; 
--insert values for this session
INSERT INTO dbo.CustomSessionAttributes VALUES(@@SPID, 'SomeAttr', 'SomeValue');

--retreive attribute value
SELECT AttributeValue 
FROM dbo.CustomSessionAttributes 
WHERE
    SessionID = @@SPID 
    AND AttributeName = 'SomeAttr';

注意可以根据需要增加属性值大小和类型，不需要解析.

Note that you can increase the attribute value size and type as needed, and no parsing is needed.

方法 5:使用存储过程 sp_set_session_context 存储会话范围的名称/值对并使用 SESSION_CONTEXT() 函数.此功能是在 SQL Server 2016 和 Azure SQL 数据库中引入的.

Method 5: Use stored procedure sp_set_session_context to store session-scoped name/value pairs and retrieve the values with the SESSION_CONTEXT() function. This feature was introduced in SQL Server 2016 and Azure SQL Database.

EXEC sp_set_session_context 'SomeAttr', 'SomeValue';
SELECT SESSION_CONTEXT(N'SomeAttr');

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