Login and User - two terminologies which are often confused by the new database developers. What is that credential called which is used to connect to a Sybase server? Is it a Login or a User?
To settledown this confusion and give a clear picture to the reader we must first clarify that logins and users - these terms are very vaguely used in computer science every now and then and as far as Sybase is concerned here also we find many people using different terms to specify something else. For example we will often find developers saying - what is the user id and password for logging into the server. As you can see that the above statement is completly incorrect as user is the person who wants log in to the sybase server however that person uses appropriate credentials to login to the system which is actually a pair of login name aka login and password.
To clarify it further we must know that login's basic purpose is to allow a security check on which ever person or application tries to enter into our Server. hence it tries to authenticate and validate the user which could be either a person or an application.
Once the correct user has logged in we must try to provide an identity to the login which has connected to our server and hence have a User attached to this Login. The purpose of User is to restrict or allows access to various parts of databases and also for attaching the ownership to the database objects. Therefore if we do not want to allow certain login to access certain database we can restrict this user by not associating it with an appropriate user id in that particular database.
Now enough of the theory and coming to practical aspect. A login as allows access to the server hence has an appropriate entry in the syslogins table on the master database of the Sybase server while a User attached to a particular login has entries in the sysalternates or sysusers tables in each database. In case, there is no entry for a login in sysusers or sysalternates tables of a particular database then the user is not allowed access to that particular database provided there is no guest user in the database otherwise the required login will be able to connect to the database using guest user.
That explained we can now understand that well there is a Login and there is a User and neither Login is a User nor User is a Login. Happy coding until next article.
To settledown this confusion and give a clear picture to the reader we must first clarify that logins and users - these terms are very vaguely used in computer science every now and then and as far as Sybase is concerned here also we find many people using different terms to specify something else. For example we will often find developers saying - what is the user id and password for logging into the server. As you can see that the above statement is completly incorrect as user is the person who wants log in to the sybase server however that person uses appropriate credentials to login to the system which is actually a pair of login name aka login and password.
To clarify it further we must know that login's basic purpose is to allow a security check on which ever person or application tries to enter into our Server. hence it tries to authenticate and validate the user which could be either a person or an application.
Once the correct user has logged in we must try to provide an identity to the login which has connected to our server and hence have a User attached to this Login. The purpose of User is to restrict or allows access to various parts of databases and also for attaching the ownership to the database objects. Therefore if we do not want to allow certain login to access certain database we can restrict this user by not associating it with an appropriate user id in that particular database.
Now enough of the theory and coming to practical aspect. A login as allows access to the server hence has an appropriate entry in the syslogins table on the master database of the Sybase server while a User attached to a particular login has entries in the sysalternates or sysusers tables in each database. In case, there is no entry for a login in sysusers or sysalternates tables of a particular database then the user is not allowed access to that particular database provided there is no guest user in the database otherwise the required login will be able to connect to the database using guest user.
That explained we can now understand that well there is a Login and there is a User and neither Login is a User nor User is a Login. Happy coding until next article.
Great!.. Cleared my confusion!
ReplyDeleteSybase logins can have roles which contributes to the boundary of actions one can perform after logging in.
ReplyDeleteI am still not sure what role does "User" play in deciding authorizations. Is it related to database groups ?