I have 2 server A and Server B(remote 3rd party) both SQL server 2012. We need to query the data from remote Server B, we are planning to use either view or stored procedure. The query contain multiple joins to fetch data from around 10 tables(minimum 10 tables is there in initial analysis may be more tables will be added in future).
If we are going to access the data through VIEW then we are going to write the below query
SELECT * FROM view-name WHERE Column1 ='abc'
My first question
Q1. I have a doubt whether this query will load all the data from table joined in the view and then the WHERE condition implement as in the VIEW definition we are not implementing the filter condition. If it is like that then this will be a performance issue, Please correct me if it is like this or not.
Q2. Which will has better performance a stored procedure or view.
Q3. How to call a remote stored procedure or View. linked server is not allowed.
Does the 4 part server.DB.Schema.SPorView name will work.
I had search and find about OPENROWSET/OPENQUERY does it works without linked server.
Please let me know if need further clarification
Thanks
Related
I just have two servers [sm33ooo.net] and [sm22ooo.net] , i would like to make query between two different tables (tbl_doc) in server [sm33ooo.net] and (tbl_archive) in [sm22ooo.net] using oracle sql developer ,any idea ?
you should be able to create a DBLINK on one of the databases which will allow you to query a table on that database from the other database. I'm not sure of your setup from your post so you might need to look into the difference between private and public dblinks to decide what is relevant to you.
For example if you add your link to server sm33ooo.net called dblink then on server sm22ooo.net you will be able to write select * from tbl_doc#dblink;
A view that references a remote server
4part name ([ServerName], [DatabaseName], [Owner], [Object Name]
OpenQuery
Which is better performance?
Why is performance good?
AFAIK, it depends a lot on your remote server type.
With recent SQL version (2016) on both server (local and remote), I didn't noticed any difference.
If your remote server is anything else (postgres, mysql...) your really should use OpenQuery as it executes the query on the remote server, getting only the correct resultset. If you use the 4 part name, SQL server will order and filter on local.
For example, take a 4 million record table and execute a query like :
SELECT * FROM reoteserver.database.schema.table where id = 4
With openquery, sql server will get only the record with id 4. Without, it will get all the table, and then filter it to get the id 4.
Late to the party here, but the difference essentially is that 4 part queries are executed locally, thus cannot utilise indexes or keys since the local server doesn't know about them. Instead it essentially retrieves the entire object, then applies the filter. On a small table, you would be unlikely to notice a difference, but on a table with millions of rows, you'd notice a difference. Openquery essentially tells the remote server to execute the query on it's behalf then pass the result back.
General rule I would say is;
NEVER join on to a table using 4 part. Only join using Openquery and I would even avoid that where possible, but that's more of a personal preference.
However, 4 part SP execution i.e. EXEC ServerName.DBName.SchemaName.ObjectName is essentially the same since that also tells the remote server to execute the query on its behalf.
I got a task to create a view based on 10 SQL queries, which are stored in one of the tables. In this table, there are two columns. First of them is Site, and the second is mentioned before SQL query.
Now, there whole deal is, that I would like to create a view, with two columns - first would be the name of the Site and the second one would be whatever ID mentioned query returns.
Can anyone please tell me how to execute this string as a query?
I have done something like this couple years ago on SQL Server (using procedure), non the less on Neteeza I can't figure how this should works; as a further complication, we are forbidden to use procedures an PROD.
I am new to access. I am using a tool/access database someone built, and it has an ODBC connection to an Oracle SQL database in it.
There are different queries on the side panel, and some of them are delete queries.
If I run these delete queries will they just modify data in my local access database without modifying the data in the Oracle Database?
Yes these will change something in the database whether its linked with another access database table or oracle table and within the database. To review the query you can open the queries in design view and run a normal select query so you can see what the queries are deleting. You can have a normal table image and or globe with a arrow in front pointing towards the table then its linked. A lot of times when I am testing I just run select queries and then I make a copy of what I will be deleting just in case anything goes wrong.
I need to pull a large amount of data from various tables across a line that has very low bandwidth. I need to minimize the amount of data that gets sent too and fro.
On that side is a Sybase database, on this side SQL Server 2008.
What I need is to pull all the tables from the Sybase database that have to do with this office. Lets say I have the following tables as an example:
Farm
Tree
Branch
etc.
(one farm has many trees, one tree has many branches etc.)
Lets say the "Farm" table has a field called "CountryID", and I only want the data for where CountryID=12. The actual table structures I am looking at are very complex (and I am also not very familiar with them) so I want to try to keep the queries simple.
So I am thinking of setting up a series of views:
CREATE VIEW vw_Farm AS
SELECT * from Farm where CountryID=12
CREATE VIEW vw_Tree AS
SELECT * from Tree where FarmID in (SELECT FarmID FROM vw_Farm)
CREATE VIEW vw_Branch AS
SELECT * from Tree where BranchID in (SELECT BranchID FROM vw_Branch)
etc.
To then pull the actual data across I would then do:
SELECT * from vw_Farm into localDb.Farm
SELECT * from vw_Tree into localDb.Tree
SELECT * from vw_Branch into localDb.Branch
etc.
Simple enough to set up. I am wondering how this will perform though? Will it perform all the SELECT statements on the Sybase side and then just send back the result? Also, since this will be an iterative process, is it possible to index the views for subsequent calls?
Any other optimisation suggestions would also be welcome!
Thanks
Karl
EDIT: Just to clarify, the views will be set up in SQL Server. I am using a linked server using Sybase ASE to set up those views. What is worrying me in particular is whether the fact that the view is in SQL Server on this side and not on Sybase on that side will mean that for each iteration the data from the preceeing view will get pulled across to SQL Server first before the calculations get executed. I want Sybase to do all the calcs and just pass the results across.
It's difficult to be certain without testing, but my somewhat-relevant experience (using linked servers to platforms other than Sybase, and on SQL Server 2005) has been that using subqueries (such as your code for vw_Tree and vw_Branch) more or less guarantees that SQL Server will pull all the data for the outer table into a local temp table, then match it to the results of the inner query.
The problem is that SQL Server has no access to the linked server's table statistics, so can make no meaningful decisions about how to optimise the query.
If you want to be sure to have the work done on the Sybase server, your best bet will be to write code (could be views or stored procedures) on the Sybase side and reference them from SQL Server.
Linked server connections are, in my experience, not particularly resilient over flaky networks. If it's available, you could consider using Integration Services rather than linked-server queries - but even that may not be much better. You may need to consider falling back on moving text files with robocopy and bcp.