Microsoft's docs on schema ownership don't go beyond saying "Schemas can be owned by any database principal, and a single principal can own multiple schemas." (MSDN doc)
I get that schemas are a way of containing different security permissions, but what is the purpose of assigning an owner to a schema and what special privileges does that user who owns the schema receive as opposed to simply being a member of the schema?
An owner of a schema is like the sysadmin within that schema, can create , drop, select , update, delete , alter objects, give permissions to other users , revoker permissions of other users and pretty much everything .
On the other hand a user with in a schema can only do the operations according to what database role was given to them , for example will be assigned these permission as Permission to create objects, db_datareader can only issue select statements against tables, db_datawriter can do inserts/updates and the list goes on.
You dont want every user who has access to database to do all sorts of operations, some people will have less access some will requires more access, hence the different roles to suit user specific needs.
Ownership of schema has it roots with the problem we had in past before sql server 2005 when there were no schemas and objects were owned by users. To separate users from objects schemas were introduced and the concept of "Schema Ownership" was introduced, it is just another way of saying that this user has all the permissions in a schema.
Related
I am not so into SQL Server and I have the following doubt: I have to require the creation of an user that can work on some databases. This user have to create\delete table, insert\delete records in these tables.
What type of permission have to be set for this user on these databases? Is dbowner ok to perform these operations? (in particular is very important that this user can create\delete tables) or am I missing something?
Just to understand first the benefits of using roles :
Roles are a part of the tiered security model:
Login security—Connecting to the server
Database security—Getting access to the database
Database objects—Getting access to individual database objects and
data**
Predefined database roles
You may need to create your own, but you have access to several predefined database roles:
db_owner: Members have full access.
db_accessadmin: Members can manage Windows groups and SQL Server
logins.
db_datareader: Members can read all data.
db_datawriter: Members can add, delete, or modify data in the tables.
db_ddladmin: allows a user to create, drop, or modify any objects within a database, regardless of who owns.
db_securityadmin: Members can modify role membership and manage
permissions.
db_bckupoperator: Members can back up the database.
db_denydatareader: Members can’t view data within the database.
db_denydatawriter: Members can’t change or delete data in tables or
views.
Fixed roles :
The fixed server roles are applied serverwide, and there are several predefined server roles:
SysAdmin: Any member can perform any action on the server.
ServerAdmin: Any member can set configuration options on the server.
SetupAdmin: Any member can manage linked servers and SQL Server
startup options and tasks.
Security Admin: Any member can manage server security.
ProcessAdmin: Any member can kill processes running on SQL Server.
DbCreator: Any member can create, alter, drop, and restore databases.
DiskAdmin: Any member can manage SQL Server disk files.
BulkAdmin: Any member can run the bulk insert command.
From the SQL Documentation:
Members of the db_owner fixed database role can perform all
configuration and maintenance activities on the database, and can also
drop the database in SQL Server.
Are you certain that is the right that you want to grant this user? It seems like a more restricted set of permissions would be more suitable for them.
For example, the roles db_ddladmin, db_datareader, and db_datawriter could be more suitable:
db_ddladmin:
Members of the db_ddladmin fixed database role can run any Data
Definition Language (DDL) command in a database.
db_datareader:
Members of the db_datareader fixed database role can read all data
from all user tables.
db_datawriter:
Members of the db_datawriter fixed database role can add, delete, or
change data in all user tables.
Alternatively, you can grant specific privileges to the user account against that database and it's user objects in order to restrict their access to the functionality subset you want.
As per my understanding each database user is assigned a role. Each role owns a certain schema. The point of role then is to determine which schema a database user has access to.
Why not just remove the role and associate users directly with schemas?
Roles do not only manage the permissions at schema level. Roles are combinations of priviliege, that provide many other levels of control such as which user can access which database object (tables, procedures, ...), what type of queries it may execute (select, update, delete, insert), and so on.
Bottom line, roles give a flexible, fine-grained control over the way users access and use the database.
For more information see the sql-server documentation.
I have an Oracle DB and I am using the system username. Using C# I created a few tables using the system username/password. When I log into sql developer and view the privileges on that table, it does not show the system user (which has a dba role and a MGMT_USER role) as having select/insert/update/delete permissions (or any permissions for that matter).
"You may not GRANT/REVOKE privileges to/from yourself"
Why does my admin user not have access to these tables and how do I get it?
What #TenG said - you can't grant privs on objects you own to yourself - you have those privs inherently as the OWNER.
More importantly, DO NOT use the SYSTEM account to create objects, especially don't create them IN the SYSTEM schema.
Use SYSTEM to create your application user, log in as THAT user, and THEN create your objects.
In Oracle, being the owner of the means you have implicit grants on the tables.
No need to grant privs to yourself on your own objects.
I am looking for the best way to setup an Oracle database so that multiple roles can share a single schema with tables.
I would have, for example, several roles:
Application User
N Developer Users
DBA User
... future user types
I have been able to create groups, grant privileges to other schemas, and create a logon trigger to switch the schema on logon. However, users are not able to view tables through SQL Developer.
SQL Developer will only show the objects owned by the current user, not those that are owned by the session's current_schema setting, in the tree view unless you go to Other Users and choose the schema you're interested in. In order to see objects owned by other users, you're realistically going to have to navigate to the appropriate schema. If there are a large number of schemas in the database, you can right click on Other Users and create a filter that limits the set of users that are returned to just the schema you care about.
I am new to schema, roles and user management part in sql server. Till now I used to work with simple dbo schema but now after reading few articles I am intrested in creating schema for managing my tables in a folder fashion.
At present, I want to create a schema where i want to keep my tables that have same kind of functionality. When I tries to create a schema then I faces a problem while using query, permissions etc.
First of all i want to get used to of using schemas then only I want to explore it. But due to initial stages and work pressure as well i m not able to implement it yet.
What can i do to start using schema with default permissions as that of dbo.
Also let me know about creating roles and assigning roles on these schema. I want all this to be accessible by sa user itself at present.
What is the concept behind all these things
Basically
The schema has an owner
Objects in different schemas can access each other with no extra permissions if they have the same owner
Please see my question here: "SQL Server: How to permission schemas?" and RBarryYoung's enlightening answer...