What's the way to query more than one database using SQL*Plus?
In MySQL it's possible to do something like this :
create table WK_LINK_JOINT_IDEOREQ AS
select k.constraint_name cn, k.table_name tl, l.column_name lc
, k.referenced_table_name tg, k.column_name cg, l.referenced_table_name td
, l.referenced_column_name cd
from information_schema.KEY_COLUMN_USAGE k
It's just an example, it's not complete : but as you can see, we are working on two databases, INFORMATION_SCHEMA and another one.
I want to do somthing like this using SQL*Plus, but the problem is that when we connect using SQL*Plus, we specify the database (SID) which means that the others are not accessible.
Is there a way to do it?
Oracle has a different interpretation of DATABASE from MySQL. In Oracle we have multiple users or schemas in the same database.
So, if what you really want is to access objects from a different schema all that has to happen is for that schema to grant you privileges. You can then reference the tables (or whatever) in your SQL.
User JOE grants you select on his table
SQL> conn JOE/SOAP
SQL> grant select on my_table to ABC;
You can then run queries on it:
SQL> conn ABC/DEF
SQL> select * from joe.my_table;
In your example you used INFORMATION_SCHEMA. The Oracle equivalent of this is the data dictionary, an enormous library of views. Find out more.
Public access is granted by default on most of them. So you can select from USER_TABLES, USER_CONSTRAINTS and USER_CONS_COLUMNS to re-create that query (assuming I have understood it correctly).
Related
When I want to select from table Y in database X I can use
select * from [X].[dbo].[Y]
or
USE X
select * from [Y]
Is there any reason to prefer one over the other?
dbo
Using dbo as the owner of all the database objects can simplify managing the objects. You will always have a dbo user in the database. Users in the database will be able to access any object owned by dbo without specifying the owner as long as the user has appropriate permission.
USE X
When a SQL Server login connects to SQL Server, the login is automatically connected to its default database and acquires the security context of a database user. If no database user has been created for the SQL Server login, the login connects as guest. If the database user does not have CONNECT permission on the database, the USE statement will fail. If no default database has been assigned to the login, its default database will be set to master.
Understanding the Difference between Owners and Schemas in SQL Server
USE (Transact-SQL)
I'd tend to use [server].[database].[schema].[table] in instances where a script may query mutliple tables from multiple databases.
The USE [database] would typically be used in scenarios where all statements were to apply to the same database and you needed to make sure they were applied to the correct database. Have you ever connected to a server and run a script only to find you ran it on the master database?
USE X will change the context to X and all the following statements will execute under the context X.
But X.dbo.Y will access the object Y without changing the current context.
Eg: Let us consider there is two databases DB1 and DB2. DB1 contains table T1 & T2 and DB2 contains tables U1 & U2.
Now,
USE DB1 -- here context set to DB1
select * from T1 -- works fine
select * from U1 -- gives error, because U1 is not in current context
select * from DB2.dbo.U1 -- works fine, because it access the context DB2 from current content context DB1
select * from T2 -- works fine
USE DB2 -- here context changed to DB2
select * from U2 -- works fine
select * from T1 -- gives error, because T1 is not in current context
select * from DB1.dbo.T1 -- works fine, because it access the context DB1 from current content context DB2
by using first Query you can perform that selection from other databases.In the same window you can have the selection for other data beses also.
But By using second selection, From the same window you can have selection for that(USE X) databse only.
Sometimes you want the schema and database to be dictated by the login, and in this case you should simply use the object name. That's one reason to not fully qualify them.
How can I restrict some users in DB2, not to see the table structure. I set the user privilege and restrict user from table access. so that user can not select data or change table but still can see the table structure or describe it.
This problem refers to row access in tables which is added in db2 version 10.
I had this problem too.
you can use this version - if applicable- and restrict user access from specific table structures.
You need to remove the select grant on catalog tables. For example, the following query should return 0 rows when executing with q restricted user.
db2 "select tabschema, tabname from syscat.tables"
All tables and views in the following schemas should not have select on public, nor in any group the restrictive user is in.
sysibm
syscat
db2 revoke select on SYSIBM.SYSTABLES from username
We have an Oracle DBMS (11g) and the following configuration:
A DB user "MYUSER"
Two schemas "MYUSER" and "SCHEMA_B"
User "MYUSER" can access "SCHEMA_B" and has READ permissions on its tables
A public DB link "DB_LINK" located in "SCHEMA_B"
The DB_LINK is working when using the DB user "SCHEMA_B" directly
Question: When logged on as "MYUSER", what is the correct syntax to access tables using the DB link of "SCHEMA_B"? Is it possible to do so at all?
I already tried several constellations, which all did not work:
select * from dual#"DB_LINK"
select * from dual#"SCHEMA_B"."DB_LINK"
select * from dual#SCHEMA_B."DB_LINK"
select * from dual#SCHEMA_B.DB_LINK
select * from SCHEMA_B.dual#DB_LINK
select * from "SCHEMA_B".dual#DB_LINK
The error message I receive is:
ORA-02019. 00000 - "connection description for remote database not found"
Thanks for any suggestion!
I don't think it is possible to share a database link between more than one user but not all. They are either private (for one user only) or public (for all users).
A good way around this is to create a view in SCHEMA_B that exposes the table you want to access through the database link. This will also give you good control over who is allowed to select from the database link, as you can control the access to the view.
Do like this:
create database link db_link... as before;
create view mytable_view as select * from mytable#db_link;
grant select on mytable_view to myuser;
I had the same problem
I used the solution offered above -
I dropped the SYNONYM, created a VIEW with the same name as the synonym.
it had a select using the dblink ,
and gave GRANT SELECT to the other schema
It worked great.
Using SQL server 2000 and Access 2003
Access Database Name - History.mdb
Access Table Name - Events
SQL Database Name - Star.mdf
SQL Table Name - Person
I want to take the field from person table, and include in Events table by using inner join
Tried Query
Select * from Events inner join person where events.id = person.id
So How to make a query for access and sql databases.
I want to make a Select query in access only. Not an sql Database.
Need Query Help?
While you can (possible, should -- why?) use a linked table, there are as ever more than one way to skin a cat. Here's another approach: put the connection details into the query test e.g. something like
SELECT *
FROM [ODBC;Driver={SQL Server};SERVER=MyServer;DATABASE=Star;UID=MyUsername;Pwd=MyPassword;].Person AS P1
INNER JOIN
[MS Access;DATABASE=C:\History;].[Events] AS E1
ON S1.seq = S2.seq
WHERE E1.id = P1.id;
You can set up a linked table in Access to your SQL Server, and the instructions on how to do so vary slightly in Access versions. Look in the help file for "Linked Table", or go here if you have Access 2007.
Once you have a linked table set up, you'll be able to access the SQL Server table in your query. Note that optimizing a linked table join takes some work.
You can create a linked table in Access, that points to the table in SQL. The rest you can achieve in the query designer.
You should add the msaccess db as a remote server.
then you can do that join
I have a large db with many tables and sprocs, and I want to find and see, for example, if there is a table with a name that has "setting" as part of it. I'm not very familiar with SqlServer's System Databases like master, msdb etc., I know there is a way to query one of those dbs to get what I need back, does someone know how to do it?
Thank you,
Ray.
SQL Server also supports the standard information schema views. Probably better to use them, since this query should also work across different database engines if you ever need to do a migration:
SELECT * FROM INFORMATION_SCHEMA.tables where table_name LIKE '%Settings%'
the table you want is sys.objects
SELECT *
FROM sys.objects
The table with the info you seek is called sysobjects. Here's a query for what you describe:
SELECT * FROM sysobjects WHERE xtype = 'U' AND NAME LIKE '%setting%'
(U is the type for user tables)
For Sql Server 2005
SELECT * FROM sys.objects where type in ('U') and name like '%setting%'