Using Database link in applications

Hi,
i just configured and created a PUBLIC database link on my 10g oracle. I can use it successfully from sqlplus doing some simple select like:
SQL> select * from "table"@dblink
The query returns all the result as expected.
Now I would like to use this public link in my applications but the problem is that the link seems to be only available in the SYS schema.
Ho can I access from other schema?
In other words, in need to do some select (and insert) from my APEX applications using the db link. If I try the said select, all I obtain is
ORA-02019: connection description for remote database not found

Is that the actual command or what you believe you issued? Can you pull the entry from dba_db_links to verify the problem is not something as simple as you left off the word 'public' in the command?
In the old days when you used HS you also had to create an hs_tnsnames.ora, hs_listener, and an hs_initsql.ora file. Do you still create these with DG4ODBC? What about the file permissions, are there any requirements to set these in order to allow use?
I found an internet article you can check you actions against and two threads here on OTN that may be of help.
http://www.pythian.com/news/1554/how-to-access-mysql-from-oracle-with-odbc-and-sql/
How to connect to Oracle from MySQL
Oracle to connect MySQL
HTH -- Mark D Powell --

Similar Messages

TNS-12666 error occures when using database link

When I am trying to use database link
defined in my database the following error occures:
TNS-12666 Dedicated server: outbound transport protocol different from inbound.
In documentation is stated to resolve such an error to
specify the same protocol in the SQL*Net connect string or alias for the outbound connection as that used for the inbound connection.
I have in tnsnames.ora defined network service name
by which I can connect to such a database by SQL*Plus
without any problems, why can I not do such a thing
via database link?
Thanks a lot for advise, ...

Could you change the following entry in your 'sqlnet.ora' file and try?
SQLNET.AUTHENTICATION_SERVICES = (NONE)

How to Execute a Remote Procedure in Portal using Database Link

Hi,
I followed the instructions to create a Portal form for a remote procedure. But I am encountering the following error. Can someone advise what may be the cause?
Failed to execute - Missing string(create_package_body) language(us) domain (wwv) sub_domain (wwv_builder) (WWV-04300)
ORA-04020: deadlock detected while trying to lock object PUBLIC.PORTLET_SCHEMA (WWV-11230)
Failed to parse as PORTAL - (WWV-08300)
PURPOSE
How to execute a remote procedure in Portal using Database Link.
DESCRIPTION
This procedure assumes that you have two databases, one of which is remote, and Portal is configured in the other.
Remote Database A:
==================
1) Create a procedure as follows: Create or Replace PROCEDURE SCOTT.ADD_TWO_VALUES ( v_one IN NUMBER, v_two IN NUMBER, v_result OUT NUMBER) as begin v_result :=v_one+v_two; end; 2) Grant execute privileges to PUBLIC on the procedure.
Database B (where Portal is configured): ========================================
1) Create a public database link and choose to connect as a specific user (say SYSTEM). By default, in an Oracle 8i database, the "global_names" parameter in initSID.ora (or init.ora) file is set to "true". This Global Naming parameter enforces that a dblink has the same name as the database it connects to. Therefore, if the remote global database (A) name is "ora8.acme.com" then the database link should also be named as "ora8.acme.com".
2) Create a synonym for the procedure in Database A. Make sure you fully qualify the procedure name in the remote database (like SCOTT.ADD_TWO_VALUES).
3) Create a dynamic page to execute the procedure. The ORACLE tags in the dynamic page will look similar to the following: <ORACLE> DECLARE v_total NUMBER; BEGIN ADD_TWO_VALUES(:v_one,:v_two, v_total); htp.p('The total is => '); htp.p('<input type="TEXT" VALUE='||v_total||'>'); htp.para; htp.anchor('http://<machine.domain:port#>/pls/portal30/SCOTT.DYN_ADD_TWO_VALUES.show_parms', 'Re-Execute Procedure'); END; </ORACLE>
4) Portal does not have an option to create a form based on a synonym. Therefore, if you want to create a form instead of a dynamic page, create a wrapper procedure and then create a form based on this procedure. For example: Create or Replace PROCEDURE PORTAL30.ADD_TWO_VALUES_PR ( v_one IN NUMBER, v_two IN NUMBER, v_total OUT NUMBER) as begin add_two_values(v_one, v_two, v_total); end;
5) Grant execute privileges to PUBLIC on the procedure.

hello...
any input will welcomed... Thanks..

Adding user to the oracle database using database link - is it possible?

Hi, i wolud like to manage my databases using one client. I easilly operate on my distriubuted tables but i have problem with creating users in distribiuted database. Is it possible to create users in distributed database using database links? or it have to be done locally using some stored procedures or sth similar?

The SQL syntax of the CREATE USER statement doesn't support DB links, the only way to do it would be with stored procedures. There might be an Oracle SP for that or for generic remote execution of SQL, but I'm not familiar with such.

How to use database link in from6i?

I can use database link in sql plus,but i can't use it in forms6i,why? thanks

Don't know why.
What I always do is create a synonym on the local database which points (through the db link) to the object on the other database.
Regards,
Meine

How to fetch,update,insert the data using database link on diff. servers

I am using two oracle server.
1st) Oracle 9i ( Server1 )
2nd) Oracle 10g ( Server2 )
3) Forms 6i
I have created a database link on Server 1 for connecting to Server 2.
I written a piece of code which will be executed in Forms 6i and is connected to Server1.
The piece of code brings the data from SErver2 via cursor and I try to insert / update the relevant records
in my Server1 database users.
The Insert/Update runs sucessfully but at the time of commit I get the following errors
in Forms ORA-01041:internal error. hostdef does not exist.
Then it forcefully rollback the data and come out of the application.
contact :email-id : [email protected]

Suggest you test your code from sqlplus before running from forms.
Start by testing a simple "select sysdate from dual@<database link>;" then test select from application_table@<database link> then test the insert/update code. After it works from sqlplus, then try it from forms.

Using database link with a dynamic SQL in Forms 5

I have a Form 5 application where a database link is specified in a client version of dynamic SQL. The function that the application is designed to perform is to access data in a table in a remote database and use it to populate another table in a local database with the same structure as the source table. Dynamic SQL is used because the name of the table can only be resolved during run time.
The problem is that it gives error with code 'ORA-03113' and text 'End-of-file on communication channel' when you try to run it.
Is it not possible to use a database link with a dynamic SQL? What can I do to overcome the problem ?

Try to create a local view based ao the remote table and use the view.

Using database-link in view to get around ORA-01031 error

I have been granted select rights on a users table. I am therefore able to select from his table. If however I try create a view against his table I run into the ORA-01031 problem. I have worked around this problem by creating a database-link to myself and then adding that to the view creation and it works. What are the downsides of using the database-link in this way?

The only down side I have been able to identify is that a extra session is created and that the CPU has a little extra work due to the LOOP BACK that takes place. I need to ensure the network is not unnessesarly used and therefore will need to ensure that 127.0.0.1 (local host) is used in the database connection discription. e.g.
create database link my_db_link connect to scott identified by tiger using '(description=(address=(protocol=tcp)(host=127.0.0.1) (Port = 1521) ) (connect_data= (sid=ora10g)))';

20 Index Restriction on Remote Tables (i.e. using Database Links)

The Oracle Database Administrator's Guides for 10g and 11g document a performance restriction that "No more than 20 indexes are considered for a remote table." If I go back to the 8i documentation it says "In cost-based optimization, no more than 20 indexes per remote table are considered when generating query plans. The order of the indexes varies; if the 20-index limitation is exceeded, random variation in query plans may result."
Does anyone have more details on this performance restriction? In particular I am trying to answer these questions:
1) Are the 20 indexes which are considered by the CBO still random in 10g?
2) Can I influence which indexes are considered with index hints or will my hints only be considered if they are for one of the "random" 20 indexes which are being considered by the CBO?
3) Are there any other approaches or work-arounds to this restriction assuming you need to select from a large remote table with more than 20 indexes (and need to perform the selection using 1 of those indexes to get adequate performance) or do we need to abandon database links for this table?
Thanks in advance for your input.

So, here's my simple test.
SQL>
SQL> create table gurnish.indexes20plus ( n1 number, n2 number, n3 number, n4 number, n5 number, n6 number, n7 number,
2 n8 number, n9 number, n10 number, n11 number, n12 number, n13 number, n14 number, n15 number, n16 number,
3 n17 number, n18 number, n19 number, n20 number, n21 number, n22 number, n23 number, n24 number,
4 n25 number, n26 number, n28 number);
create index xin1 on indexes20plus (n1);
Table created.
SQL> SQL> create index xin2 on indexes20plus (n2);
create index xin3 on indexes20plus (n3);
Index created.
SQL> SQL>
Index created.
SQL> SQL> create index xin4 on indexes20plus (n4);
Index created.
SQL> SQL>
Index created.
SQL> SQL> create index xin5 on indexes20plus (n5);
create index xin6 on indexes20plus (n6);
Index created.
SQL> SQL>
Index created.
SQL> SQL> create index xin7 on indexes20plus (n7);
Index created.
SQL> SQL> create index xin8 on indexes20plus (n8);
Index created.
SQL> SQL> create index xin9 on indexes20plus (n9);
Index created.
SQL>
SQL> create index xin10 on indexes20plus (n10);
Index created.
SQL> SQL> create index xin11 on indexes20plus (n11);
create index xin12 on indexes20plus (n12);
create index xin13 on indexes20plus (n13);
Index created.
SQL> SQL>
Index created.
SQL> SQL>
Index created.
SQL> SQL> create index xin14 on indexes20plus (n14);
Index created.
SQL> SQL> create index xin15 on indexes20plus (n15);
Index created.
SQL>
SQL> create index xin16 on indexes20plus (n16);
Index created.
SQL>
SQL> create index xin17 on indexes20plus (n17);
Index created.
SQL> SQL> create index xin18 on indexes20plus (n18);
Index created.
SQL> SQL> create index xin19 on indexes20plus (n19);
Index created.
SQL> SQL> create index xin20 on indexes20plus (n20);
Index created.
SQL> SQL> create index xin21 on indexes20plus (n21);
Index created.
declare
i number;
begin
for i in 1..100
loop
dbms_random.seed(i+100);
insert into indexes20plus values (dbms_random.value(1,5),dbms_random.value(1,21),dbms_random.RANDOM, dbms_random.RANDOM,dbms_random.value(1,20),
dbms_random.value(1,4),dbms_random.value(1,6), dbms_random.value(1,7),dbms_random.value(1,9),dbms_random.value(1,10),
dbms_random.value(1,11),dbms_random.value(1,12),dbms_random.value(1,13),dbms_random.value(1,14),dbms_random.value(1,1),
dbms_random.value(1,1),dbms_random.value(1,19),dbms_random.value(1,122),dbms_random.value(1,20),dbms_random.value(1,20)
,dbms_random.value(4,20),dbms_random.value(1,20),dbms_random.value(1,20),dbms_random.value(1,20),dbms_random.value(1,20)
,dbms_random.value(4,20),dbms_random.value(4,20));
end loop;
commit;
end;
SQL> set autotrace traceonly
SQL> l
1* select * from gurnish.indexes20plus@lvoprds where n1 = 4
SQL> /
no rows selected
Execution Plan
Plan hash value: 441368878
| Id | Operation | Name | Rows | Bytes | Cost (%CPU
)| Time | Inst |
| 0 | SELECT STATEMENT REMOTE | | 1 | 351 | 1 (0
)| 00:00:01 | |
| 1 | TABLE ACCESS BY INDEX ROWID| INDEXES20PLUS | 1 | 351 | 1 (0
)| 00:00:01 | LVPRD |
|* 2 | INDEX RANGE SCAN | XIN1 | 1 | | 1 (0
)| 00:00:01 | LVPRD |
Predicate Information (identified by operation id):
2 - access("A1"."N1"=4)
Note
- fully remote statement
- dynamic sampling used for this statement
Statistics
0 recursive calls
0 db block gets
0 consistent gets
0 physical reads
0 redo size
1897 bytes sent via SQL*Net to client
481 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
0 rows processed
SQL> select * from gurnish.indexes20plus@lvoprds where n21 = 4;
no rows selected
Execution Plan
Plan hash value: 2929530649
| Id | Operation | Name | Rows | Bytes | Cost (%CPU
)| Time | Inst |
| 0 | SELECT STATEMENT REMOTE | | 1 | 351 | 1 (0
)| 00:00:01 | |
| 1 | TABLE ACCESS BY INDEX ROWID| INDEXES20PLUS | 1 | 351 | 1 (0
)| 00:00:01 | LVPRD |
|* 2 | INDEX RANGE SCAN | XIN21 | 1 | | 1 (0
)| 00:00:01 | LVPRD |
Predicate Information (identified by operation id):
2 - access("A1"."N21"=4)
Note
- fully remote statement
- dynamic sampling used for this statement
Statistics
1 recursive calls
0 db block gets
0 consistent gets
0 physical reads
0 redo size
1897 bytes sent via SQL*Net to client
481 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
0 rows processed
SQL>

How can i get data from another database SQL Server use database link from

I have a database link from Oracle connect to SQL Server database with user cdit connect default database NorthWind.How can I get data from another database(this database in this SQL Server use this database link)?

hi,
u should see following documentation:
Oracle9i Heterogeneous Connectivity Administrator's Guide
Release 1 (9.0.1)
Part Number A88789_01
in it u just go to chapter no. 4 (using the gateway),,u'll find ur answer there.
regards
umar

Unable to access remote database object using database link

Hi all,
I have created a database link to a remote server
SQL> create database link remote_link connect to lax_dba identified by lax_dba using 'abc.corp.com';
database link created
when i am trying to access any table of lax_dba
sql> select * from laxtab@remote_link;
i am getting this Ora error
ORA-12514: TNS:listener does not currently know of service requested in connect
I need your help please to solve this issue
Thanks n Regards
Laxman

The database server where you defined the link (not your PC) has resolved 'abc.corp.com' to a server/port/service combination using its tnsnames.ora, sqlnet.ora and possibly ldap.ora settings. You can try
tnsping abc.corp.comon the server (as ReubenC suggested) to see what it's attempting to connect to. (It's important to do this on the database server and not on your PC as they will have different tns settings etc.)
It has then found the server and found a listener running on it (so you're getting close), but that remote listener doesn't recognise the service you're asking for. It might be something like the '.com' suffix.

Insert using database link

Now connected to database B :
INSERT INTO abc_hesids
          (     abc_key,
               hesid,
               date_added,
               date_updated,
               dob,
               sex,
               newnhsno,
               homeadd,
               procode3,
               lopatid
          SELECT     'X',
                    0,
                    sysdate,
                    sysdate,
                    HES_Common.f_string_field('X', 1),
                    HES_Common.f_string_field('X', 2),
                    HES_Common.f_string_field('X', 3),
                    HES_Common.f_string_field('X', 4),
                    HES_Common.f_string_field('X', 5),
                    HES_Common.f_string_field('X', 6)
          FROM dual
The above INSERT has been reduced down to bare minimum with the following error occurring :
HES_Common.f_string_field('X', 1),
ERROR at line 18:
ORA-02069: global_names parameter must be set to TRUE for this operation
SQL>
The abc_hesids table exists in database A and this insert is running in database B. A database link exists such that abc_hesids is a synonym for the table of the same name in database A.
I want Oracle to insert into the table in database A but use the package HES_Common in database B. I think this is possible but have not done this sort of thing for a while. Note : the package HES_Common exists in both databases A and B
Any ideas on how to get Oracle to use the local version of the package - do I have to get the DBA to change global_names to TRUE ??

ORA-02069 global_names parameter must be set to TRUE for this operation
Cause: A remote mapping of the statement is required but cannot be achieved because GLOBAL_NAMES should be set to TRUE for it to be achieved.
Action: Issue ALTER SESSION SET GLOBAL_NAMES = TRUE if possible.

Problem with using database link from oracle 7 to oracle 9i

Hi To Every One
I have two oracle database oracle 7.3.4.0.1 and oracle 9i 9.2.0.1.0.
and the tns alias to connect to oracle 9i database is oracle9i and tns
alias to oracle 7 database is oracle7.I have no problem in connect to
these database using these tns aliases from either database.The tns
alias for oracle 7 is available in tnsnames.ora file of oracle9i and
tns alias for oracle 9i is available in tnsnames.ora file of oracle 7.
So there is no connection problem from each other.Connection is
working fine for each other but the problem with database links is
like this
Problem:
when i create database link from oracle9i user or public database link
from oracle9i for oracle7 user like this
SQL ORACLE9I >CREATE DATABASE LINK ORACLE7 CONNECT TO <ORACLE7USER>
IDENTIFIED BY <PASSWORD> USING 'ORACLE7';
OR
SQL ORACLE9I >CREATE PUBLIC DATABASE LINK ORACLE7 CONNECT TO <ORACLE7USER>
IDENTIFIED BY <PASSWORD> USING 'ORACLE7';
The links get created sucessfully but when i write command like
SQL ORACLE9I> DESC <ORACLE7USER_NAME>.<ORACLE7USER_TABLENAME>@ORACLE7
I RECEIVE A ORACLE ERROR LIKE
ORA-12663 SERVICE REQUIRED BY CLIENT IS NOT AVAILABLE ON THE SERVER.
OR IF MY COMMAND IS LIKE
SQL ORACLE9I> SELECT <FEILD_NAME> FROM
<ORACLE7USER_NAME>.<ORACLE7USER_TABLENAME>@ORACLE7;
I RECEIVE AN ORACLE ERROR LIKE
ORA-01002 FETCH OUT OF SEQUENCE.
ORA-02063: preceding line from ORACLE7
BUT IF I CREATE A LINK FROM ORACLE7 USER FOR ORACLE9I USER
IT WORKS FINE.
PLZ HELP ME WHAT IS THE PROBLEM THAT THE LINK FOR ORACLE 7 IS NOT WORKING WHEN
IT IS BEING CREATED FROM ORACLE9I.
Thank u.

Oracle 9.2.0 does not support connectivity to Oracle 7. The newest version that will support this is 9.0.1.

Timeout when using database link connecting to a remote database

Hi,
I have another strange problem. I have two computers A and B. Both have an Oracle database server instance. I manage the one in B (which is my local computer) but not the one in A (which is a computer where I have a user account and an Oracle account but I don't own or manage).
I tried to establish a database link on the database in B pointing to the one in A. This works.
When I try the opposite, that is, establish a database link on the database in A pointing to the one in B I cannot get it work. I can create the database link but then when I try to use it (e.g., by submitting a "SELECT") it blocks for a long time and finally returns "ORA-12535: TNS:operation timed out". I tried to execute telnet from A to B using the port of the Oracle database server in B and it seems that the connection is established. I tried something similar with tnsping but this does not work, as I get again the timeout. I tried deactivating the firewall on my computer B, but it does not work either (besides, the telnet passes through even if I have the firewall activated).
Any idea?
My TNSPING looks like this:
tnsping '(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = <the-target-ip>)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = XE)
I also tried with:
tnsping '(ADDRESS = (PROTOCOL = TCP)(HOST = <the-target-ip>)(PORT = 1521))';
I'm lost... Any ideas are very much appreciated.
Thanks!

From A to B and from B to A can you ping ... post the output surrounded by tags for formatting.
Do the same thing for TNSPING.
What do these computers have in the way of firewalls and antivirus products installed and how are they configured?

Problems in using database link

Hi all,
I have problems in using the following created database link:
Name: fzanalyze
User: fzanalyze
PWD: xxx
Host: fz.domain.com
I get the following error message, if I try to start this select:
select * from tab@fzanalyze;
FEHLER in Zeile 1:
ORA-12154: TNS:Couldn't resolve service name
The problem, the TNS is correct, because I copied the hoststring from the tnsnames.ora. Also I can connect to the database by using the given hostname as follows:
connect fzanalyze/[email protected]
connected
What could be the problem, the I get the tns-Error, although I can connect normal to the database??
Thanks for helping
Dana

Dana,
Unlike Kamal, I don't use SQLNET anymore (isn't it obsolete from 8i+?), so I don't have any sqlnet.ora on my client or server.
I'm not really a sysop, so no clever thoughts behind the following ideas, I just use these for development purposes at home:
IP range at home = 192.168.x.x segment (another router server connects to the internet)
Oracle server computer name = dbserver.seinpost.nl (local address = 192.168.1.110)
instance entry in $TNS_ADMIN/listener.ora @ server:
    (SID_DESC =
      (GLOBAL_DBNAME = inst04.seinpost.nl)
      (ORACLE_HOME = /u01/app/oracle/product/10.1.0/db_1)
      (SID_NAME = inst04)
    )instance entry in $TNS_ADMIN/tnsnames.ora @ server:
INST04.SEINPOST.NL =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.seinpost.nl)(PORT = 1521))
    (CONNECT_DATA =
      (SERVICE_NAME = inst04.seinpost.nl)
)instance entry in tnsnames.ora @ client:
INST04 =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS =
        (PROTOCOL = TCP)
          (HOST = 192.168.1.110)
            (PORT = 1521)
    (CONNECT_DATA =
      (SERVICE_NAME = inst04.seinpost.nl)
)So again, no sqlnet.ora and as you can see only on my client I use local IP addresses to prevent my client for searching the internet for the non-existing dbserver.seinpost.nl address
Hope this helps,
Michiel

Using Database link in applications

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