BLOGS

How to verify and then create a specific SQL users?

It is always a best practise to validate whether the logins & user exists before creating a new one in SQL Server. You can verify this by using the system tables (syslogins & sysusers). I have given below T-SQL queries to validate first and then create. To access any specific database, a login creation is a mandatory. If the login already exists, you can still verify it with syslogins and then create the user for any new databases.

–Check the logins first for the SQL Server
USE [master]
GO
SELECT name FROM sys.syslogins;
GO
SELECT name FROM sys.sysusers;
GO

–Check the users for any specific databases.
USE [AdventureWorks2012]
GO
SELECT name FROM sys.sysusers
GO

After reviewing the available logins & users for the SQL Server and specific databases, and according to your company policies in naming convention, you then can create users accordingly. But before that need to drop the user if exists with the below queries.

–IF EXISTS DROP USER & LOGINS for a SQL user named ServiceAct_App1
USE [AdventureWorks2012]
GO
IF EXISTS (SELECT name FROM sys.sysusers WHERE name = N’ServiceAct_App1′)
DROP USER ServiceAct_App1
GO
USE [master]
GO
IF EXISTS (SELECT name FROM sys.sysusers WHERE name = N’ServiceAct_App1′)
DROP USER ServiceAct_App1
GO
IF EXISTS (SELECT name FROM sys.syslogins WHERE name = N’ServiceAct_App1′)
DROP LOGIN ServiceAct_App1
GO

In here, I am creating login & user after dropping it with if exists statement.

–CREATE LOGIN, CREATE USER, ASSIGN ROLES for Applications – Service Account
USE [master]
GO
CREATE LOGIN [ServiceAct_App1] WITH PASSWORD=N’YSM2015′, DEFAULT_DATABASE=[AdventureWorks2012], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF
GO
USE [AdventureWorks2012]
GO
CREATE USER [ServiceAct_App1] FOR LOGIN [ServiceAct_App1]
GO
ALTER ROLE [db_datareader] ADD MEMBER [ServiceAct_App1]
GO
USE [master]
GO
CREATE USER [ServiceAct_App1] FOR LOGIN [ServiceAct_App1]
GO
ALTER ROLE [db_datareader] ADD MEMBER [ServiceAct_App1]
GO