FILE_IDEX (Transact-SQL)

บทความ
09/03/2024

Applies to: SQL Server Azure SQL Managed Instance

This function returns the file identification (ID) number for the specified logical name of a data, log, or full-text file of the current database.

Transact-SQL syntax conventions

Syntax

FILE_IDEX ( file_name )

Arguments

file_name
An expression of type sysname that returns the file ID value 'FILE_IDEX' for the name of the file.

Return Types

int

NULL on error

Remarks

file_name corresponds to the logical file name displayed in the name column from the sys.master_files or sys.database_files catalog views.

Use FILE_IDEX in a SELECT list, a WHERE clause, or anywhere that supports use of an expression. For more information, see Expressions (Transact-SQL).

Examples

A. Retrieving the file id of a specified file

This example returns the file ID for the AdventureWorks_Data file.

USE AdventureWorks2022;  
GO  
SELECT FILE_IDEX('AdventureWorks2022_Data') AS 'File ID';  
GO

Here's the result set.

File ID   
-------   
1  
(1 row(s) affected)

B. Retrieving the file id when the file name is not known

This example returns the file ID of the AdventureWorks log file. The Transact-SQL (T-SQL) code snippet selects the logical file name from the sys.database_files catalog view, where the file type equals 1 (log).

USE AdventureWorks2022;  
GO  
SELECT FILE_IDEX((SELECT TOP (1) name FROM sys.database_files WHERE type = 1)) AS 'File ID';  
GO

Here's the result set.

File ID   
-------   
2

C. Retrieving the file id of a full-text catalog file

This example returns the file ID of a full-text file. The T-SQL code snippet selects the logical file name from the sys.database_files catalog view, where the file type equals 4 (full-text). This code returns 'NULL' if a full-text catalog does not exist.

SELECT FILE_IDEX((SELECT name FROM sys.master_files WHERE type = 4))  
AS 'File_ID';

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