I know sybase supports two types of temp tables, one starts with # and can't be shared by sessions. The other one is created with tempdb.. prefix which can be shared by sessions or users.
My question is:
Are tables created in tempdb accessible to other users as well?
How to control the access or how to prevent the table created by userA from being modified/dropped by userB?
I googled for a while but didn't find any information on this.
I'm using sybase at work but don't have admin access to create new user so I can't do the test.
Can someone who have experience please advise?
please refer to http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.infocenter.dc32300.1570/html/sqlug/X10118.htm for details.
i also test the behavior on sybase ase 15.7.
the result as same as the previous link.
Are tables created in tempdb accessible to other users as well?
Yes.
How to control the access or how to prevent the table created by userA from being modified/dropped by userB?
There seems no method about the tempdb..xxx tables.
Related
I am trying to share my Snowflake Database(default metadata)--> Account_Usage schema --> Query_History table to another managed account (i.e. reader account) but the data is not visible in another account.
is there any way to share the snowflake database without duplicating the data?
I am getting error as Already Imported Database (i.e) SNowflake cannot be shared for Datashare option.
for a Managed account for usage, I Snowflake database and schemas are available but are not able to see the data which is available.
According to the documentation you can't re-share any database that is shared with you:
Shared databases and all the objects in the database cannot be forwarded (i.e. re-shared with other accounts).
Since the Snowflake database is one that is shared to you from Snowflake, this is probably why you're having issues.
If you need to do this your best bet is to create a table and populate it with the data you need from the Snowflake database and share that table instead. Although it is strange that you'd want to share this info with another account.
Your other option would be to create database/schema in your account with views over the account usage data that you want to share, create a role that can access only that, and then provide a user login with that role only to the group needing to do analytics on your data.
I plan to pass exam 'Querying Microsoft SQL Server 2012'. I would like to better understand one question.
Question is:
How would you accomplish this task?
You work as a database developer
at ABC.com. ABC.com has a SQL Server 2012 database named SalesDB with
a table named Invoices. Application developers are developing several
in-house applications that will access the Invoices table. You need to
develop a solution that will allow the applications to access the
table indirectly while still allowing them to update the Invoice
table. How would you accomplish this task?
possible answers are.
A. You should create a view on the Invoices table.
B. You should create a columnstore index on all columns used by the
applications.
C. You should allow the applications access to the Invoices table via
stored procedures.
D. You should drop and recreate the Invoices table as a partitioned
table. Possible answers are
This is source: How would you accomplish this task?
They say that correct answer is C, but I don't know why? I think that correct is A, because view works 'indirectly' with data.
Thank for help.
The commented ownership-chaining of stored procs only come into place when the stored proc and the used tables have the same owner.
So I would like to point out another argument.
You can EXECUTE a stored proc AS another user. That means you could create a user without a login and grant UPDATE permissions. Let's say the name of the user is UPDATEInvoices. When you create a stored proc you can define that it has to execute as the comtext of the user.
So, when you give the user who wants to call the stored proc EXECUTE permissions he can UPDATE rows in the table because it runs with other permissions.
I have MS Access as a front end and PostgreSQL as back end for my database. So I set up the database in PostgreSQL and linked the tables to MS Access using the ODBC drivers. Everything works great, I can update the tables in MS Access and the record will appear in Postgres database.
Since I can still see the linked tables in MS Access, I feel like it is possible for some users to go in and manually modify the tables without filling out proper forms. Is it possible to HIDE the tables or lock the tables so that Access users cannot modify the raw data at all? If not, what can I do to secure the integrity of the database.
Thanks!
I would recommend looking at Postgres privileges as a way to lock the tables down.
In short, you could have your backend run as one user that has full access permissions on the tables in question, and when the users login to the app, they would be connected to Postgres using a user whose privileges are considerably more locked down (say, read only if you just want to be able to do SELECTs to surface data).
For example, you could run the following SQL against your Postgres server:
REVOKE ALL ON accounts FROM joe;
GRANT SELECT ON accounts TO joe;
Which would first remove all privileges from the user joe for the table accounts, and then allow only SELECT priveleges for that table.
You could do something similar for all the tables you wish to lock down. You'll also need to do the same for the sequences used by those tables.
You may wish to create a special readonly user which has only read access across the board, and use those credentials to surface the Postgres data for the users to access.
When you need to alter data, your backend could specifically use a power user of sorts which has much greater access.
Here's a link which details creating a readonly Postgres user (for purposes of backups in this case, but the general concept and the SQL commands should apply (just ignore the stuff about pg_dump).
If you aren't concerned about users' ability to modify the data in those tables via the up other than in the ways that are authorized, but are only concerned about them using, say, psql to go in and update them, then you probably don't need a readonly user, but can simply lock the tables down and have the backend use that user with sufficient access.
I am using SQL Server 2008R2 and one of the things I am trying to do is allow users read-only access to some of the tables in one of the DBs via MS Access ODBC so that they cna build their own reports, etc (Their request). The problem is that they can see all of the system views /tables (information_schema and merge replication stuff). Is there anyway that I can revoke these so that all they can see are the tables /views I designate as available for selection?
Not sure what I can do to limit what they see as "available".
Thanks,
S
Put them on the public role, and only give SELECT permission to the tables/views you want.
You can't stop them from seeing the system views but you can stop them viewing what those views return. If they don't have permission on the table, sys.tables will not return that table.
I have a couple of questions.
1) Why cannot we see system tables (like sysobjects) under Master/Model/MSBD etc.? But we
can query. Are we basically querying the views, because as they are the main tables that
holds a value able informations?
Like "SELECT * FROM sysobjects". are we basically querying some views?
2) Why cannot we add triggers to system tables?
Thanks in advance
SQL Server 2008 system tables (http://msdn.microsoft.com/en-us/library/ms179932.aspx) have been implemented as read-only views. One cannot directly work with the data in these system tables. You can access SQL Server metadata using catalog views. Do check this link http://msdn.microsoft.com/en-us/library/ms174365.aspx
It is possible to create triggers on system tables but it is generally not recommended. Please check this http://www.sql-server-performance.com/faq/trigger_system_table_p1.aspx
cheers
Since SQL 2005 the catalog views are implemented as views declared in the Resource Database (mssqlsystemresource). Due to some special magic they appear to exist in every database.
You can always use the execution plan to see from what actual tables do these views fetch data from. The underlying tables can be accessed when you are connected with a DAC connection. Modifying the system tables in any way will mark the database and an message will be logged every time the database starts up. Modified databases are not supported by MS, so if something goes wrong you cannot ask for support.