DB_ID (Transact-SQL)

Статия
06/20/2023

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

This function returns the database identification (ID) number of a specified database.

Transact-SQL syntax conventions

Syntax

DB_ID ( [ 'database_name' ] )

Arguments

'database_name'
The name of the database whose database ID number DB_ID will return. If the call to DB_ID omits database_name, DB_ID returns the ID of the current database.

Return types

int

Remarks

DB_ID may only be used to return the database identifier of the current database in Azure SQL Database. NULL is returned if the specified database name is other than the current database.

Note

In Azure SQL Database, DB_ID may not return the same value as the database_id column in sys.databases and sys.database_service_objectives. These two views return database_id values that are unique within the logical server, while DB_ID and the database_id column in other system views return values that are unique within a single database or within an elastic pool.

Permissions

If the caller of DB_ID does not own a specific non-master or non-tempdb database, ALTER ANY DATABASE or VIEW ANY DATABASE server-level permissions at minimum are required to see the corresponding DB_ID row. For the master database, DB_ID needs CREATE DATABASE permission at minimum. The database to which the caller connects will always appear in sys.databases.

Important

By default, the public role has the VIEW ANY DATABASE permission, which allows all logins to see database information. To prevent a login from detecting a database, REVOKE the VIEW ANY DATABASE permission from public, or DENY the VIEW ANY DATABASE permission for individual logins.

Examples

A. Returning the database ID of the current database

This example returns the database ID of the current database.

SELECT DB_ID() AS [Database ID];  
GO

B. Returning the database ID of a specified database

This example returns the database ID of the AdventureWorks2022 database.

SELECT DB_ID(N'AdventureWorks2008R2') AS [Database ID];  
GO

C. Using DB_ID to specify the value of a system function parameter

This example uses DB_ID to return the database ID of the AdventureWorks2022 database in the system function sys.dm_db_index_operational_stats. The function takes a database ID as the first parameter.

DECLARE @db_id INT;  
DECLARE @object_id INT;  
SET @db_id = DB_ID(N'AdventureWorks2022');  
SET @object_id = OBJECT_ID(N'AdventureWorks2022.Person.Address');  
IF @db_id IS NULL   
  BEGIN;  
    PRINT N'Invalid database';  
  END;  
ELSE IF @object_id IS NULL  
  BEGIN;  
    PRINT N'Invalid object';  
  END;  
ELSE  
  BEGIN;  
    SELECT * FROM sys.dm_db_index_operational_stats(@db_id, @object_id, NULL, NULL);  
  END;  
GO

Examples: Azure Synapse Analytics and Analytics Platform System (PDW)

D. Return the ID of the current database