I'm running a query across a database link to a Sybase server from Oracle.
In it's where clause is a restriction on date, and I want it tied to sysdate, so something like this:
select * from some_remote_view where some_numeric_key = 1 and
some_date > sysdate+2
The problem is, when I do explain plan, only the condition some_numeric_key = 1 shows up in the actual sql that is getting remoted to the sybase server. Oracle is expecting to perform the date filter on its side.
This is causing a performance nightmare - I need that date filter remoted across to have this query working quickly
Even if I try something like casting the sysdate to a charcater string like this:
to_char(sysdate-2,'YYYY-MM-DD')
It still does not remote it.
Is there anything I can do to get Oracle to remote this date filter across the db link to Sybase?
Doing integration between Oracle and other platforms I often run into this problem, not just with SYSDATE but with other non-standard functions as well.
There are two methods to work around the issue, the first being the most reliable in my experience.
First, you can create a view on the remote db with the filters you need, then on the Oracle side you just select from the new view without additional filters.
Second, if you are not allowed to create objects on the remote side, try using bind variables (of the correct data type!) in your Oracle SELECT statement, e.g.:
declare
v_some_date constant date := sysdate + 2;
begin
insert into oracle_table (...)
select ...
from remote_table#db_link t
where t.some_numeric_key = 1
and t.some_date > v_some_date;
commit;
end;
/
Related
Dear Techies,
Our application triggers queries like below very frequently.
select name,emp_id,prod_id,prod_name, .... from appuser.table where emp_id=:1 and prod_id=:2;
We usually spend ample amount of time finding the SQL_ID when we receive the problematic SQL_TEXT. We have an option in SQL*Plus for variables like emp_id, prodnum, etc.. as below
VARIABLE emp_id NUMBER; EXEC :emp_id := 101;
However, we have :1, :2 as bind variables name which can't be set before running the SQL as these are mere number (although treated as bind variables by Oracle). We can't ask Application vendor to rebuild all queries removing these numbered bind variables.
So, I was looking for any of the below option in SQL*Plus:
How to declare/define such bind variables (:1, :2, etc...) before running the SQL?
Can we bypass in any way the bind values and send this SQL to cursor cache in Oracle? Looks to be difficult but still wanted to give a try asking.
Can we pass the values of these bind variables (:1, :2, etc..) during runtime as we do in Toad & SQL developer? This way we can track the correct SQL_ID from the cursor (v$sql).
I have been trying and searching for various options but didn't get specific to mine. Any help in this regard would be greatly appreciated. Any version of Oracle database which addresses this concern would be fine.
I'm here to ask for your help, so my probleme is:
I have created report with jasperrerport 3.7.6 (queries based on oracle).
and now I'm trying to use the same report with PostgreSql Database and I'm getting errors for specific oracle functions like (NVL, sysdate ...), and I don't want to change the query for now (unless I have to).
Is there any thing to use to make autoconversion when executed on a postgresql database?
If there are no matching functions in both databases, consider creating your own functions which will "simulate" the originals.
For example, for Oracle's SYSDATE:
create or replace function f_sysdate return date is
begin
return sysdate;
end;
I don't know PostgreSQL, but - you'd do the same in that database. Function's name must be the same: F_SYSDATE.
Then, in JasperReports, instead of calling "originals", you'd call your own functions, e.g.
select ename, job, sal,
f_sysdate --> this
from emp
where deptno = 10
Doing so, report would work in both databases. True, you'd have to put some initial effort, but - it might pay off in the future.
I'm using Oracle SQL Developer version 4.02.15.21.
I need to write a query that accesses multiple databases. All that I'm trying to do is get a list of all the IDs present in "TableX" (There is an instance of Table1 in each of these databases, but with different values) in each database and union all of the results together into one big list.
My problem comes with accessing more than 4 databases -- I get this error: ORA-02020: too many database links in use. I cannot change the INIT.ORA file's open_links maximum limit.
So I've tried dynamically opening/closing these links:
SELECT Local.PUID FROM TableX Local
UNION ALL
----
SELECT Xdb1.PUID FROM TableX#db1 Xdb1;
ALTER SESSION CLOSE DATABASE LINK db1
UNION ALL
----
SELECT Xdb2.PUID FROM TableX#db2 Xdb2;
ALTER SESSION CLOSE DATABASE LINK db2
UNION ALL
----
SELECT Xdb3.PUID FROM TableX#db3 Xdb3;
ALTER SESSION CLOSE DATABASE LINK db3
UNION ALL
----
SELECT Xdb4.PUID FROM TableX#db4 Xdb4;
ALTER SESSION CLOSE DATABASE LINK db4
UNION ALL
----
SELECT Xdb5.PUID FROM TableX#db5 Xdb5;
ALTER SESSION CLOSE DATABASE LINK db5
However this produces 'ORA-02081: database link is not open.' On whichever db is being closed out last.
Can someone please suggest an alternative or adjustment to the above?
Please provide a small sample of your suggestion with syntactically correct SQL if possible.
If you can't change the open_links setting, you cannot have a single query that selects from all the databases you want to query.
If your requirement is to query a large number of databases via database links, it seems highly reasonable to change the open_links setting. If you have one set of people telling you that you need to do X (query data from a large number of tables) and another set of people telling you that you cannot do X, it almost always makes sense to have those two sets of people talk and figure out which imperative wins.
If we can solve the problem without writing a single query, then you have options. You can write a bit of PL/SQL, for example, that selects the data from each table in turn and does something with it. Depending on the number of database links involved, it may make sense to write a loop that generates a dynamic SQL statement for each database link, executes the SQL, and then closes the database link.
If you want need to provide a user with the ability to run a single query that returns all the data, you can write a pipelined table function that implements this sort of loop with dynamic SQL and then let the user query the pipelined table function. This isn't really a single query that fetches the data from all the tables. But it is as close as you're likely to get without modifying the open_links limit.
I am using Oracle SQL Developer and have a rather large query built. The query is going to be run on a monthly or quarterly basis. I was wondering if there was a way that I can do a declare statment up top and then in the code just reference these variables created. That way when someone wants to run the query they can just change the dates at the top of the code rather then have to dig through all of it. I am kind of new to Oracle SQL Developer but I know in other sql codes I built I could simply declare the variable and then set it and then in the code call the variable name. Below is an example of what I know how to do but i am having trouble in Oracle SQL Developer.
Example: I have a data base that contains the columns Business, business type(small,medium,large) number of deposits, deposit amount and deposit date. I want to build a query that outputs a quarterly summary of the number of deposits and the deposit amount and be able to change the quarter and size of the business.
Example Code from my previous SQL expereince this is an example of what I am trying to do since i can not disclose my code with the table names etc in them.
Declare #busstype,#qbegindate,#qenddate
Set #busstype = 'small'
Set #qbegindate = '01-JAN-2013'
Set #qenddate = '01-MAR-2013'
Select business,numberofdeposits,depositamount
From business_transactions
Where ('#qbegindate'<=depositdate<='#qenddate'
And businesstype = '#busstype')
Group By Business
The results would list out the businesses name and then the total deposits and total amount.
I know this code is not right but its just an example of what I am looking to do in Oracle SQL Developer. The query I have built is working fine I just find it a pain to dig through the code to change dates and criteria and was wondering how I would do something like this since i have figured out that I am not able to do this in ORACLE Sql Developer.
Here is an example with predefined variable:
set feedback off
var abc varchar2
begin
:abc := 'abc';
end;
/
select :abc as a from dual;
Output:
A
--------------------------------
abc
Common table expressions allow variables to be defined at the top of the query. For performance and style reasons this is generally not a good way to
use common table expressions. The advantage is this query can be run in any IDE and it is completely self-contained.
--Variables - change these before running.
with busstype as (select 'small' value from dual),
qbegindate as (select date '2013-01-01' value from dual),
qenddate as (select date '2013-03-01' value from dual)
--Query - do not modify code below.
select business,numberofdeposits,depositamount
from business_transactions
where depostiddate between
(select value from qbegindate)
and
(select value from qenddate)
and businesstype = (select value from busstype)
group by business, numberofdeposits,depositamount;
yesterday I've been trying to make this code work inspite the fact it's just working fine with nhibernate and SQL server but when it come to oracle it generate wrong sql
UnitOfWork.Current.CreateCriteria<Bill>().Add(Restrictions.IsEmpty("ReqId"))
.SetMaxResults(BatchSize).SetLockMode(LockMode.Upgrade).List<Bill>();
the generated SQL will something like
Select * from
(Select bill_0.id,bill_0.BillNo ...... from Bill bill_0 where bill_0.reqId is Not null )
where ROWNUM < 10 for UPDATE of bill_0.ID
so i wont run because the allies bill_o is defined inside the inner sql statement so who got the solution ?
the correct sql would be something like this which i tried and worked on oracle db
Select bill_0.id,bill_0.BillNo ...... from Bill bill_0
where bill_0.reqId is Not null and ROWNUM < 10 for UPDATE of bill_0.ID
Since, as you say, NHibernate is generating invalid Oracle SQL, I suggest you file a bug with the NHibernate people. The SQL would work if the in-line view had been assigned an alias of "bill_0", or if the FOR UPDATE clause didn't use a table alias ("for UPDATE of ID"). Whether you can modify your NHibernate calls to make either of these happen I'm afraid I have no idea.