SESSION_CONTEXT (Transact-SQL)

Artikkeli
23.05.2023

Applies to: SQL Server 2016 (13.x) and later Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

Returns the value of the specified key in the current session context. The value is set by using the sp_set_session_context (Transact-SQL) procedure.

Transact-SQL syntax conventions

Syntax

syntaxsql

SESSION_CONTEXT(N'key')

Arguments

'key'
The key (type sysname) of the value being retrieved.

Return Type

sql_variant

Return Value

The value associated with the specified key in the session context, or NULL if no value has been set for that key.

Permissions

Any user can read the session context for their session.

Remarks

SESSION_CONTEXT's MARS behavior is similar to that of CONTEXT_INFO. If a MARS batch sets a key-value pair, the new value will not be returned in other MARS batches on the same connection unless they started after the batch that set the new value completed. If multiple MARS batches are active on a connection, values cannot be set as "read_only." This prevents race conditions and non-determinism about which value "wins."

Examples

The following simple example sets the session context value for key user_id to 4, and then uses the SESSION_CONTEXT function to retrieve the value.

SQL

EXEC sp_set_session_context 'user_id', 4;  
SELECT SESSION_CONTEXT(N'user_id');

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