SQL Error 4060: Cannot open database requested by the login

 SQL Server Error 4060 indicates that the login attempt to a specific database has failed. The full error message typically looks like this:

Cannot open database "DatabaseName" requested by the login. The login failed. Login failed for user 'UserName'.

Common Causes and Solutions

1. Database Does Not Exist

Cause: The database specified in the connection string does not exist on the SQL Server instance.

Solution: Verify that the database name in the connection string is correct and that the database exists on the server.

SELECT name FROM sys.databases WHERE name = 'DatabaseName';

2. Insufficient Permissions

Cause: The login does not have the necessary permissions to access the database.

Solution: Grant the appropriate permissions to the user.

USE master;
GRANT CONNECT TO [UserName];
USE [DatabaseName];
ALTER USER [UserName] WITH LOGIN = [UserName];

3. User Not Mapped to Database

Cause: The login is not mapped to a user in the database.

Solution: Map the login to a user in the database.

USE [DatabaseName];
CREATE USER [UserName] FOR LOGIN [UserName];

4. Database in Single-User Mode

Cause: The database is in single-user mode and another user is already connected.

Solution: Change the database to multi-user mode.

ALTER DATABASE [DatabaseName] SET MULTI_USER;

5. Database is Offline

Cause: The database is set to offline mode.

Solution: Set the database to online mode.

ALTER DATABASE [DatabaseName] SET ONLINE;

6. Login with Default Database Issue

Cause: The login’s default database is not accessible or does not exist.

Solution: Change the default database for the login.

ALTER LOGIN [UserName] WITH DEFAULT_DATABASE = [ExistingDatabase];

Example Troubleshooting Steps

Here is a structured approach to troubleshoot SQL Server Error 4060:

• Verify Database Existence: Check if the database exists on the server.

SELECT name FROM sys.databases WHERE name = 'DatabaseName';

• Check User Mapping: Ensure the login is mapped to a user in the database

USE [DatabaseName];
SELECT name FROM sys.database_principals WHERE name = 'UserName';

• Check Database Status: Verify that the database is online and in multi-user mode.

SELECT state_desc FROM sys.databases WHERE name = 'DatabaseName';

        To bring the database online and set it to multi-user mode if necessary:

ALTER DATABASE [DatabaseName] SET ONLINE;
ALTER DATABASE [DatabaseName] SET MULTI_USER;

• Grant Necessary Permissions: Ensure the login has the necessary permissions.

USE master;
GRANT CONNECT TO [UserName];
USE [DatabaseName];
ALTER USER [UserName] WITH LOGIN = [UserName];

• Check Default Database: Verify and change the default database for the login if required.

ALTER LOGIN [UserName] WITH DEFAULT_DATABASE = [ExistingDatabase];

Example Scenario

Suppose you encounter the error message while trying to connect to a database named SalesDB with a user named SalesUser. Follow these steps:

• Check if SalesDB exists:

SELECT name FROM sys.databases WHERE name = 'SalesDB';

• Check user mapping in SalesDB:

USE [SalesDB];
SELECT name FROM sys.database_principals WHERE name = 'SalesUser';

• Check the status of SalesDB:

SELECT state_desc FROM sys.databases WHERE name = 'SalesDB';

        If the database is offline, bring it online:

ALTER DATABASE [SalesDB] SET ONLINE;

• Ensure SalesUser has access to SalesDB:

USE master;
GRANT CONNECT TO [SalesUser];
USE [SalesDB];
ALTER USER [SalesUser] WITH LOGIN = [SalesUser];

• Check and set the default database for SalesUser:

ALTER LOGIN [SalesUser] WITH DEFAULT_DATABASE = [SalesDB];

By following these steps, you should be able to diagnose and resolve the SQL Server Error 4060, ensuring that the login can successfully access the requested database.

SQL Server Error 18456 - Login failed for user

 SQL Server Error 18456 is a common error indicating that the login attempt for a user has failed. The error message will typically look like this:

Login failed for user 'username'. (Microsoft SQL Server, Error: 18456)

Understanding Error 18456

This error can have various reasons depending on the state code provided in the error message. The state code helps to pinpoint the exact cause of the login failure. Here are some common state codes and their meanings:

State Codes and Their Meanings:

• State 1: Generic error.
• State 2: User ID is not valid.
• State 5: User ID is not valid.
• State 6: Attempt to use a Windows login name with SQL Server Authentication.
• State 7: Login disabled and password mismatch.
• State 8: Password mismatch.
• State 9: Invalid password.
• State 11 and 12: Valid login but server access failure.
• State 13: SQL Server service paused.
• State 18: Password must be changed.

Common Causes and Solutions

1. Invalid Username or Password

• State 8: Password mismatch.
• State 9: Invalid password.

Solution: Verify that the username and password are correct. Ensure that you are using the correct authentication method (Windows or SQL Server).

2. Account Locked or Disabled

• State 7: Login disabled and password mismatch.

Solution: Check if the account is locked or disabled in SQL Server. You can unlock or enable the account using the following query:

ALTER LOGIN [YourUserName] WITH PASSWORD = 'NewPassword' UNLOCK;

3. Invalid Login Name

• State 2 and 5: User ID is not valid.

Solution: Verify the login name. Ensure that the login exists in SQL Server.

4. Password Expiration

• State 18: Password must be changed.

Solution: Change the password for the user.

ALTER LOGIN [YourUserName] WITH PASSWORD = 'NewPassword';

5. Server Access Failure

• State 11 and 12: Valid login but server access failure.

Solution: Ensure the user has the necessary permissions to access the database. Grant the required permissions if necessary.

6. Windows Authentication Issue

• State 6: Attempt to use a Windows login name with SQL Server Authentication.

Solution: Ensure you are using the correct authentication mode. Switch to Windows authentication or create a SQL Server login.

7. SQL Server Service Paused

• State 13: SQL Server service paused.

Solution: Restart the SQL Server service.

Example of Troubleshooting Steps

Here is a structured approach to troubleshoot SQL Server Error 18456:

• Check the Error Log: Look for the error in the SQL Server error log to find the state code.

EXEC xp_readerrorlog 0, 1, N'Login failed';

• Verify User Credentials: Ensure the username and password are correct.
• Check Account Status: Ensure the account is not locked or disabled.

SELECT name, is_disabled FROM sys.sql_logins WHERE name = 'YourUserName';

• Review Permissions: Ensure the user has the necessary permissions.

USE YourDatabase;
EXEC sp_change_users_login 'Update_One', 'YourUserName', 'YourLoginName';

• Check Authentication Mode: Ensure SQL Server is configured for the correct authentication mode.

SELECT SERVERPROPERTY('IsIntegratedSecurityOnly');

By following these steps, you should be able to diagnose and resolve the specific cause of SQL Server Error 18456.