Joining to remote table

- I have two databases A and B
- A has a db link to B
I want to execute a select query in A which joins to a table in B using db link.
select * from a_table where id in ( select id from b_table@B )
Now the problem is, even though the local 'a_table' is very small, the remote table in B is really huge and hence the query is very slow.
It seems like the join operation brings the whole remote data to A for performing the join.
My question is, is it possible to do the other way? That is is, take the small 'a_table' to the remote database, perform the join there and then bring back the data.
Any other hints/thoughts to solve this also is greatly appreciated.

I am really sorry. The sample query was the other way round. A mistake in my description.
I want to select data from B which joins to a table in A using db link.
select * from b_table@B where id in ( select id from a_table )
Arun, Thanks for the reply. But I am not sure if it will solve problem of transporting data from one db to another for performing the join.

Similar Messages

Problem encountered when join two remote tables in a materialized view

I'm using oracle 9.2.0.6
1> I have two tables:
CREATE TABLE TEST
A VARCHAR2(100 BYTE),
C DATE
CREATE TABLE TEST1
A VARCHAR2(100 BYTE),
B TIMESTAMP
2>. I defined a prebuild table:
CREATE TABLE MV_TEST1
ID1 ROWID,
A VARCHAR2(100 BYTE),
ID2 ROWID,
B TIMESTAMP(6),
C DATE
3> I created mview logs:
CREATE MATERIALIZED VIEW LOG ON PSI_TEST.TEST
WITH ROWID
INCLUDING NEW VALUES;
CREATE MATERIALIZED VIEW LOG ON PSI_TEST.TEST1
WITH ROWID
INCLUDING NEW VALUES;
4> when I create mview:
CREATE MATERIALIZED VIEW PSI_TEST.MV_TEST1
ON PREBUILT TABLE WITH REDUCED PRECISION
REFRESH FAST ON DEMAND
WITH PRIMARY KEY
AS
select
test.rowid id1,
test.a,
test1.rowid id2,
test1.b,
cast(null as date) c
from test , test1
where test.a = test1.a(+);
It is created successfully.
5> problem:
when I use remote tables to do the same thing, say test and test1 are in another instance and are connected by a dbLink, I couldn't create the mview successfully:
CREATE MATERIALIZED VIEW PSI_TEST.MV_TEST1
ON PREBUILT TABLE WITH REDUCED PRECISION
REFRESH FAST ON DEMAND
WITH PRIMARY KEY
AS
select
a.rowid id1,
a.a,
b.rowid id2,
b.b,
cast(null as date) c
from test@dbl a, test1@dbl b
where a.a = b.a(+);
when run above statement, I got:
ORA-12015: cannot create a fast refresh materialized view from a complex query
Any ideas? Or joining two table through a dblink for a mview is not allowed at all?
Thanks in advance.

No one has a clue?
Message was edited by:
lzhwxy

Oracle BUG (CASE + remote tables + inline view)

Oracle 9.2.0.8
BUG: Oracle inserts NULL when we use CASE statement in the SELECT query and we join a remote table with inline view.
Script:
CREATE TABLE t1 (a number(19,4)OK.
SELECT (case when b = 1 then c else d end)
FROM t2@Remote LEFT JOIN
(SELECT a FROM t3@Remote) q ON (t2.a = q.a)123
456
789
3 rows selected.
INSERT INTO TABLE t1 (a)
SELECT (case when b = 1 then c else d end)
FROM t2@Remote LEFT JOIN
(SELECT a FROM t3@Remote) q ON (t2.a = q.a)3 rows inserted.
SELECT * FROM t1<null>
<null>
<null>
3 rows selected
Oracle inserts the correct values if I:
* replace the CASE with DECODE
* join with table not with an inline view
* join local tables
Someone with registration in the Metalink can post the bug.
Best regards, Beroetz

Oracle 9.2.0.8
BUG: Oracle inserts NULL when we use CASE statement in the SELECT query and we join a remote table with inline view.
Script:
CREATE TABLE t1 (a number(19,4)OK.
SELECT (case when b = 1 then c else d end)
FROM t2@Remote LEFT JOIN
(SELECT a FROM t3@Remote) q ON (t2.a = q.a)123
456
789
3 rows selected.
INSERT INTO TABLE t1 (a)
SELECT (case when b = 1 then c else d end)
FROM t2@Remote LEFT JOIN
(SELECT a FROM t3@Remote) q ON (t2.a = q.a)3 rows inserted.
SELECT * FROM t1<null>
<null>
<null>
3 rows selected
Oracle inserts the correct values if I:
* replace the CASE with DECODE
* join with table not with an inline view
* join local tables
Someone with registration in the Metalink can post the bug.
Best regards, Beroetz

Update openquery remote table with join

Hi All,
I have a problem with OPENQUERY update on remote table. I've googled for days, and can't solve the problem.
Here is the problem:
Local server MS SQL 2005.
Remote server: MySQL.
The linked server is communicating through MySQL ODBC 5.1
I created the following code for update (tried many other version too, this is the last one):
update openquery(Remoteserver,'select products_id, products_price, products_last_modified, products_stock from products1')
set
products_price=A.products_price,
products_stock=A.products_stock,
products_last_modified=getdate()
FROM
(select * from vi_products_update) AS A INNER JOIN
openquery(octopus, 'select products_id from products1')AS B
ON A.products_id=B.products_id
When I run the query the columns are updated with the same value, for each record. It looks the value is the first which match the criteria. Each (remote and local) table has as primary key products_id. In this example I used as result set for local a view, but I have the same result if I use a table.
the products_last_modified column is updated in order, and if I update for e.g. the products_price with a constant that is ok too. The problem should be somewhere with join, but I can' get it where.
THX for any help
ab

Hi
Did you ever solve this problem
I have the same issue trying to update many rown in a MySQL table from SQL2005 using the syntax below,
UPDATE
openquery(DEV,'select id, `desc` from todLocationGroups')
SET [desc] = V.Destination_Group FROM
(select * from VTM_TOD_Rate) as V inner join
openquery(DEV,'select id, `desc` from todLocationGroups') as K
ON K.id = V.TOD_LG_ID
but i get this error
OLE DB provider "MSDASQL" for linked server "KAYOTE_DEV" returned message "Row cannot be located for updating. Some values may have been changed since it was last read.".
Msg 7343, Level 16, State 4, Line 1
The OLE DB provider "MSDASQL" for linked server "KAYOTE_DEV" could not UPDATE table "[MSDASQL]". The rowset was using optimistic concurrency and the value of a column has been changed after the containing row was last fetched or resynchronized.

Issue with query involving remote tables

Hi I have a query inside a procedure that has 4 union all statements ,2 of which are based on tables at a remote database.
The query is something like
Select col1, col2, col3…..col n from Table_a, table_b, table c where join condition and certain hard-coded conditions based on run time parameters
Union all
Select col1, col2, col3…..col n from Table_a, table_b , table c where some join condition and certain hard-coded conditions based on run time parameters
Union all
Select col1, col2, col3…..col n from Table_a@remote_db, table_b@remote_db, table c@remote_db where join condition and certain hard-coded conditions based on run time parameters
Union all
Select col1, col2, col3…..col n from Table_a @remote_db, table_b @remote_db, table c@ remote_db where some join condition and certain hard-coded conditions based on run time parameters
The join conditions on the tables are quite good and when executed individually bring data in good time.The queries on the remote database also run fine when I execute them in the remote database.
However when I run this query, it doesn’t get data at all and after hours of running I have to cancel or kill it.I don’t get anything in the long-ops and in the wait class it just shows “SQL*Net message from dblink” or “SQL*Net more data to dblink”.
I thought that there could be some latency issues AND the data retreival over the dblink could be slow, so I tried the /*+driving_site(rmote table alias)*/ hint , after which it comes up in the long ops as its reading from Table a/ table b from my current database but the wait time is something like millions of seconds and it runs forever.
The issue is Table A and Table B both in the remote and the current database are huge tables with at least 40-50 million records in them.
Can anyone suggest an easy way out in this scenario, other than the hard way of re-designing the entire program(which I am afraid I might have to in the end).
Thanks

@metzquar I Put the hint in the unions where I am accessing the remote tables
@blushadow .. i was thinking about that but as these remote tables are in a sort of archived database, I dont think I will be allowed to create a mview.But thats a good suggestion.
@Earth.. I tried that , but the table population itself gets very time consuming
Thanks

Best practice for VPD and remote tables

Not specifically an HTMLDB question, but here goes...
HTMLDB 1.6 on 9.2.0.4 connecting over database link (fixed username/password) to 9.2.0.4
I've currently "wrapped" access to the remote tables in views, i.e. view "T" in the HTMLDB parsing schema LOCAL_USER is defined as "SELECT * FROM T@remote"
I'd like to put VPD controls on my backend tables, but I don't get how v('APP_USER') (or even APP_USER put into an application context) would be seen by the remote database.
Should I just put VPD policies on LOCAL_USER's views and call it a day?
Thanks for input!
-John

If you implemented the VPD in the remote database, what would your VPD be restricting? All queries would apply the policy based on the DB link fixed username resulting in all users of the HTML DB application having same policy restrictions.
The policy in the remote database does not has access to the value of v('APP_USER'). That value is only available in the database that has HTML DB. You would have to write APIs in the remote database in PL/SQL functions/procedures to pass in the V('APP_USER') value to the remote database. This is doable, but cumbersome.
If you want to have your policy modify your WHERE clause on the fly based on your HTML DB user account, then I would implement the VPD in the database which has your HTML DB repository. I am not sure which of the two scenarios below occur when doing a SELECT * FROM T.
1.) The query goes across the database link, gets all the data out of table T in the remote database, passes back to the HTML DB database, and applies the policy WHERE clause modification in the HTML DB database.
2.) The query applies the policy WHERE clause modification to the view, goes across the database link with the WHERE clause modified, and gets only the data allowed based on the policy from the remote database.
You should test this out to find out for performance purposes what query is actually performed on the remote database.
As always if anyone sees anything inaccurate in what I have written, please correct me.
Mike

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>

Performance for join 9 custom table with native SQL ?

Hi Expert,
I need your opinion regarding performance to join 9 tables with native sql. Recently i have to tunning some customize extraction cost report. This report extract about 10 million cost of material everyday.
The current program actually, try to populate the condition data and insert into customize table and join all the table to get data using native sql.
SELECT /*+ ordered use_hash(mst,pg,rg,ps,rs,dpg,drg,dps,drs) */
            mst.werks, ....................................
FROM
            sapsr3.zab_info mst,
            sapsr3.zab_pc pg,
            sapsr3.zab_rc rg,
            sapsr3.zab_pc ps,
            sapsr3.zab_rc rs,
            sapsr3.zab_g_pc dpg,
            sapsr3.zab_g_rc drg,
            sapsr3.zab_s_pc dps,
            sapsr3.zab_s_rc drs
        WHERE mst.zseq_no = :p_rep_run_id
        AND mst.werks = :p_werks
        AND mst.mandt = rg.mandt(+)
        AND mst.ekorg = rg.ekorg(+)
        AND mst.lifnr = rg.lifnr(+)
        AND mst.matnr = rg.matnr(+)
        ...............................................   unitl all table (9 tables)
        AND ps.mandt = dps.mandt(+)
        AND ps.knumh = dps.knumh(+)
        AND ps.zseq_no = dps.zseq_no(+)
        AND COALESCE (dps.kbetr, drs.kbetr, dpg.kbetr, drg.kbetr) <> 0
It seems the query ask for database to using hashed table. would that be it will burden the database ? and impacted to others sap process ?
Please advise
Thank You and Best Regards

you can only argue coming from measurements and that is not the case.
Coming from the code, I see only that you do not understand it at all, so better leave it as it is. It is not a hash table, but a hash join on these table.

Right way to preserve all parent table entries in a join with many tables!!

This problem is quite interesting to me. I have asked this question to others but no body is able to provide me with proper answers.
The problem is: How do I join a huge parent table with many child tables (more than 5 child tables) preserving all of the parent table entries. Lets say there is the parent table parentTable and three child tables childTable1, childTable2, childTable3. In order to get the data after joining these tables the query that I have been using was:
select parent.field1, parent.field2, parent.field3, child1.field4, child1.field5, child2.field6, child3.field7 from ParentTable parent, childTable1 child1, childTable1 child2, childTable3 child3 where parent.fielda = child1.fieldb and parent.fieldc = child.fieldd and parent.fielde = child.fieldf.
Although the tables are huge (more than 100,000 entries), this query is very fast, however those parent table entries which do not have child entries are lost. I know that I can left join a parent table with a child table and then with the next child table and then with the next child table and continue. Isn't there a simple solution for this commonly happening problem?
Please provide suggestions please...

Hello Lakshmi,
Although I do not know exactly how to achieve what you want to achieve but I have seen DBAs/ABAPers in my experience can run queries/scripts using the COUNT function to give the actual number of line items per table for all your 100 or odd tables.
Rgds
CONMJI

Adding a single table without a logical join to another table (OBIEE 10g)

Sometimes I want to just display a single table without a logical join to another table in the repository. However, everytime I move it to the Business Model and Mapping layer and perform a Global Consistency Check, it tells me that it needs a logical join and I am forced to create another table to join to it. Thus creating a dimension-fact relationship. There are times I don't need this relationship and just want to display some data. Is there anyway to get around this?
Thanks in advance!

Yes,You have to create a join.You cannot take single table to BMM layer.You can create an alias of the table.Join this alias and base table through any common column and take both tables to BMM and desired table to presentation layer.
Another way is to create a view in physcial layer.Write a select statement like
Select primary_key from Table
Where primary_key is primary key of base table.Join this view ith base table and repeat the steps defined for Alias.
Regards,
Sandeep

Error remote table does not contain a primary key

I make replication between oracle and Microsoft sql using getway for sql but when I insert to table in oracle I get this error in apply process
information :
ASD.SUBHI.COM is database link from oracle to microsoft sql
"DBO"."REGIONS" name of the table
CREATE TABLE regions (a INTEGER primary key) command to create table
error
ORA-26711: remote table does not contain a primary key constraint ORA-26712: remote object is "DBO"."REGIONS"@"ASD.SUBHI.COM"
Note: I go to sql server and verify that primary key is creates
is this the best place to like this question ?
if you need more details please tell me I need the answer

I make replication between oracle and Microsoft sql using getway for sql but when I insert to table in oracle I get this error in apply process
information :
ASD.SUBHI.COM is database link from oracle to microsoft sql
"DBO"."REGIONS" name of the table
CREATE TABLE regions (a INTEGER primary key) command to create table
error
ORA-26711: remote table does not contain a primary key constraint ORA-26712: remote object is "DBO"."REGIONS"@"ASD.SUBHI.COM"
Note: I go to sql server and verify that primary key is creates
is this the best place to like this question ?
if you need more details please tell me I need the answer

Instead-of Trigger of View on a Remote Table Fails!!!

Hi all,
I'm trying to create an INSTEAD OF (UPDATE or INSERT) trigger on a view V1 in DATABASE DB1 (Linux 7.3 or 7.2, ORACLE 9.2.0.1.0 - Production).The view V1 is created on a remote table through a DBLINK.But I always get such error when I update the view V1 using statements such as "update v1 set oid=oid+1000" :
ORA-03113 end-of-file on communication channel
But I can execute those statements successfully in Oracle of version 9.0.1.0.0 .
What I want to say is that if some special configs is needed to support instead-of trigger of a view on a remote table ?

Hi all,
I'm trying to create an INSTEAD OF (UPDATE or INSERT) trigger on a view V1 in DATABASE DB1 (Linux 7.3 or 7.2, ORACLE 9.2.0.1.0 - Production).The view V1 is created on a remote table through a DBLINK.But I always get such error when I update the view V1 using statements such as "update v1 set oid=oid+1000" :
ORA-03113 end-of-file on communication channel
But I can execute those statements successfully in Oracle of version 9.0.1.0.0 .
What I want to say is that if some special configs is needed to support instead-of trigger of a view on a remote table ?

Can we implement the custom sql query in CR for joining the two tables

Hi All,
Is there anyway to implement the custom sql query in CR for joining the two tables?
My requirement here is I need to write sql logics for joining the two tables...
Thanks,
Gana

In the Database Expert, expand the Create New Connection folder and browse the subfolders to locate your data source.
Log on to your data source if necessary.
Under your data source, double-click the Add Command node.
In the Add Command to Report dialog box, enter an appropriate query/command for the data source you have opened.
For example:
SELECT
    Customer.`Customer ID`,
    Customer.`Customer Name`,
    Customer.`Last Year's Sales`,
    Customer.`Region`,
    Customer.`Country`,
    Orders.`Order Amount`,
    Orders.`Customer ID`,
    Orders.`Order Date`
FROM
    Customer Customer INNER JOIN Orders Orders ON
        Customer.`Customer ID` = Orders.`Customer ID`
WHERE
    (Customer.`Country` = 'USA' OR
    Customer.`Country` = 'Canada') AND
    Customer.`Last Year's Sales` < 10000.
ORDER BY
    Customer.`Country` ASC,
    Customer.`Region` ASC
Note: The use of double or single quotes (and other SQL syntax) is determined by the database driver used by your report. You must, however, manually add the quotes and other elements of the syntax as you create the command.
Optionally, you can create a parameter for your command by clicking Create and entering information in the Command Parameter dialog box.
For more information about creating parameters, see To create a parameter for a command object.
Click OK.
You are returned to the Report Designer. In the Field Explorer, under Database Fields, a Command table appears listing the database fields you specified.
Note:
To construct the virtual table from your Command, the command must be executed once. If the command has parameters, you will be prompted to enter values for each one.
By default, your command is called Command. You can change its alias by selecting it and pressing F2.

Query remote table not working in PL/SQL

I have a problem that is killing me to figure out. Basically we trying to query a remote table through PL/SQL and it comes back with invalid column name for the table. But the table exists in the remote database and has the column. The query works fine from the same database outside of PL/SQL, just not in PL/SQL. I'll setup a test case below.
We have local database called DB1 and remote database called DB2. The table we are querying is called EMP.
First we create database link:
create database link DB2.WORLD connect to...
Test the link:
select ENAME from [email protected];
ENAME
SHAWN
Works fine.
Now we put this query inside a PL/SQL block:
declare
l_ename varchar2(20);
begin
select ename into l_ename from [email protected];
end;
This fails with the following error:
select ename
ERROR at line 274:
ORA-06550: line 274, column 7:
PL/SQL: ORA-00904: invalid column name
ORA-06550: line 271, column 3:
PL/SQL: SQL Statement ignored
ORA-06550: line 279, column 9:
PL/SQL: ORA-00904: invalid column name
ORA-06550: line 277, column 3:
PL/SQL: SQL Statement ignored
Now, I've tried changing how we select from the remote table, I've put the select statement in a cursor, tried creating a synonym which points to the remote table and selecting using the synonym in PL/SQL, it always returns the same error. But always works outside of PL/SQL.
Now the user we are connecting to the remote database as, has select on the EMP table, through a role, along with 30 other tables, all the other tables are able to be selected through the database link, in PL/SQL, it's just this one table.
Additionally I can go to another database, and create the same database link, and the query in PL/SQL works fine to the remote table. It's just this one table, from this one database, that doesn't work just in PL/SQL. Any ideas would be appreciated, I've exhausted everything.
Also, creating a copy of the table using "create table as select * from..." we can select from the copy of the table using PL/SQL through the database link. The problem is this is a central warehouse table, and is used my multiple applications and updated constantly, so dropping a recreating this table is a last resort.
Yes, this process did work, for over a year, then suddenly it stopped. Of course, no one made any changes to either database, that's always the case. I know the code didn't change though, it was still timestamped from a year ago.
Thanks in advance.

Could this be a variant on an old favourite, viz privileges being granted through roles. We cannot use objects in PL/SQL if our privileges are assigned through a role.
Maybe what has changed is that instead of being granted privileges on EMP@DB2 directly the privileges have been re-organised so that your user has them granted through a role.
Cheers, APC

Best approach to join multiple statistics tables into one

I have read different approaches to join multiple statistics tables into one, they all have a column "productobjectid".
I want to get all data for each product and put it to excel and output a jpg statistic with cfchart.
How would you do this, the sql part?
Thanks.

A couple suggestions:
1) when joining tables, its best to list both table/fields that you are joining in the FROM clause:
FROM shopproductbehaviour_views INNER JOIN shopproductbehaviour_sails ON shopproductbehaviour_views.productobjectid = shopproductbehaviour_sails.productobjectid
2) You add tables to a SQL join by placing another join statement after the SQL above:
SELECT *
FROM TableA INNER JOIN TableB on TableA.myField = TableB.myField
INNER JOIN TableC on TableA.anotherField = TableC.anotherField
3) If you have columns in the tables that are named the same, you can use column aliases to change the way they appear in your record set:
SELECT TableA.datetimecreated 'tablea_create_date', TableB.datetimecreated 'tableb_create_date'
4) Certainly not a requirement, but you might want to look into using <cfqueryparam> in your where clause:
WHERE shopproductbehaviour_sails.productobjectid = <cfqueryparam cfsqltype="CF_SQL_VARCHAR" value="#all.productobjectid#">
You might want to consider checking out one of the many tutorials on SQL available online. Many of the questions you posed in your post are covered in pretty much every basic SQL tutorial. Alternately, a good SQL book is worth its weight in gold for a beginning web applications developer.

Joining to remote table

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