I have connected Oracle database with an Azure SQL Server database via a database link.
I am trying to fetch the data of Azure SQL Server database in Oracle and it is working fine.
But when I am joining one Oracle table and one Azure SQL Server table it is taking too much time to fetch the records.
For example:.
I have one table temp_one in Oracle database and one table temp_two in Azure SQL Server database having dblink like temp.sql.hl.com.
I joined them.
SELECT "EmpAddress",EMPLOYEE_ID
FROM temp_one a
INNER join temp_two#temp.sql.hk.com b
on a.EMPLOYEE_ID = b."EmpID";
Even this normal join is taking 8 seconds.
Note: I am trying to fetch the data in Oracle.
Please help me to resolve it.
Related
I have two databases, one in SQL Server and one in Azure SQL Synapse. Now I want to have one single query that should be done between two tables from these different servers.
For example:
SQL Server name : server1
Database name : db1
Table name : tb1
Azure Synapse name : prod-synapse-2
Database name : db2
Table name : tb2
Now query should be like this:
select
tb1.col1, tb1.col2, tb2.col3, tb2.col4
from
tb1
outer join
tb2 on tb1.col5 = tb2.col5
The above query is very simple to join two tables from the same database or two tables from the 2 different database within same server.
But I want suggestions to have the above query between 2 different servers.
I have seen in many stackoverflow questions similar to this, they suggested an answer using Linked Server, but that cannot be done in my case, because I will not be provided with access to create Linked server, and link the 2 servers in Microsoft SQL Server Management Studio.
Thanks in advance
Another way to query a database hosted in a remote SQL Server is the OPENROWSET T-SQL function. To use the OPENROWSET ad hoc method, you need to provide all connection information that is required to connect to the remote SQL server and many other resources.
Using OPENROWSET requires enabling the Ad Hoc Distributed Queries advanced configuration option same as the OPENDATASOURCE function.
You need to provide the provider’s name, the connection string and the query as follows:
OPENROWSET(‘providername’,’datascource,’query)
I am using Azure SQL Database and I have two databases. I want to select one table data on the first database and merge into another (conditional) table of second database.
Is there any SQL solution to solve my problem?
We have developed a set of operational reports long back ago based on the SQL server , Currently we have added a third party source which has Oracle as source and we need to modify our existing SQL queries to pull the partial data from oracle as well. The tricky part of the requirement is we have different table from different source belong to single query
for example
SELECT A.ID , B.Name
FROM A --Belong to SQL server
INNER JOIN B --Belong to Oracle server
On A.id=B.id
I know we can have a linked server facility in SQL which allows us to grab the table B in some temp table and then join the SQL table with the temp table.
I just want to know is there any better approach to accomplish this as this would be very difficult to deal with the complex queries in case of this , Specially the sub queries and recursive queries.
Is creating a staging table with all required field from oracle and then use it in queries makes sense? as we are dealing with the operational data (though in most of the cases it is 1 day old,So we can do this).
We are using SSIS,SSRS and SQL serer 2008 R2 as development environment.
Thanks.
I have a simple Access database I use to create a number of reports. I've linked to a Teradata database server in our organization to pull some additional employee-level details. There is a simple left join on employee number, and all I pull is the name and the role.
The query without the connect takes maybe a minute or so to run and is very quick once loaded. Left joining on the Teradata connection slows everything down to a crawl. It can take 10 minutes or so to run the query through Excel. When the query is loaded in Access, scrolling through it is very slow.
I should note there's no performance issues with the Teradata server. I pull unrelated reports from the same and different tables, with complex joins and the speed is very quick.
I tried creating an even simpler query that does almost noting, and the performance issues are still there. Here is the code:
SELECT EMPL_DETAILS_CURR.NM_PREFX, EMPL_DETAILS_CURR.NM_GIVEN,
MC.DT_APP_ENTRY, MC.CHANNEL_IND
FROM MC LEFT JOIN EMPL_DETAILS_CURR ON MC.EMP_ID = EMPL_DETAILS_CURR.EMP_ID;
There are only 7000 records in MC.
If you are joining data between MS Access tables and Teradata tables the join has to be completed using the Microsoft JET Engine on your local machine. That means the data that exists in your Teradata tables is being brought down to your local machine to so that it can be joined.
If the tables are all on Teradata and accessed via linked tables in MS Access the join may still be occurring locally. I would suggest running the query as an ODBC Direct (I forget the exact term) query so that the SQL is passed on to Teradata to be executed and the results returned to MS Access when the query completes.
Problem: I have to pull data from a SQL Server database and an Oracle database and put it together in one dataset. The problem I have is: The SQL Server query requires an ID that is only found from the return of the Oracle query.
What I am wondering is: How can I approach this problem in a way such that performance is not harmed?
You can do this with linked servers or by transferring the data all to one side. It's all going to depend on the volume of data on each side.
A general rule of thumb is to execute the query on the side which has the most data.
For instance, if the set of Oracle IDs is small, but the SQL Server set is large, you make a linked server to the Oracle side and execute this on the SQL Server side:
SELECT *
FROM sqlservertable
INNER JOIN linkedserver.oracletable
ON whatever
In this case, if the Oracle side is large (or cannot be prefiltered before the need to join with the SQL Server side), the performance will normally be pretty poor - and will improve a lot by pulling the entire table (or the minimal subset you can determine) into a SQL Server table instead and do the JOIN all on the SQL Server side.