Creates SQL login and user for a database. The user is created with 3 roles: db_executor, db_datareader, db_datawriter.

Create login and user

/*------------------------------------------------------------------------------------
Server login
 -----------------------------------------------------------------------------------*/
if not exists (select 1 from sys.server_principals where name = N'MyDatabaseUser')
    create login [MyDatabaseUser]
        with password = 'password',
        default_database = [MyDatabase],
        check_policy = off,
        check_expiration = off
go


/*------------------------------------------------------------------------------------
MyDatabase user
 -----------------------------------------------------------------------------------*/
use [MyDatabase]
go

if exists (select 1 from sys.sysusers where name = N'MyDatabaseUser')
    drop user [MyDatabaseUser]
go

create user [MyDatabaseUser] for login [MyDatabaseUser] with default_schema=[dbo]

-- db_executor role might need to be created manually.
if not exists (select 1 from sys.database_principals where name = 'db_executor')
begin
  -- Create a db_executor role
	create role db_executor

	-- Grant execute rights to the new role
	grant execute to db_executor
end
go

execute sp_addrolemember @rolename = N'db_executor', @membername = N'MyDatabaseUser';
execute sp_addrolemember @rolename = N'db_datareader', @membername = N'MyDatabaseUser';
execute sp_addrolemember @rolename = N'db_datawriter', @membername = N'MyDatabaseUser';
go