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  • Can I improve performance by refactoring SQL commands into C# classes?

    - by Matthew Jones
    Currently, my entire website does updating from SQL parameterized queries. It works, we've had no problems with it, but it can occasionally be very slow. I was wondering if it makes sense to refactor some of these SQL commands into classes so that we would not have to hit the database so often. I understand hitting the database is generally the slowest part of any web application For example, say we have a class structure like this: Project (comprised of) Tasks (comprised of) Assignments Where Project, Task, and Assignment are classes. At certain points in the site you are only working on one project at a time, and so creating a Project class and passing it among pages (using Session, Profile, something else) might make sense. I imagine this class would have a Save() method to save value changes. Does it make sense to invest the time into doing this? Under what conditions might it be worth it?

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  • Including associations optimization in Rails

    - by Vitaly
    Hey, I'm looking for help with Ruby optimization regarding loading of associations on demand. This is simplified example. I have 3 models: Post, Comment, User. References are: Post has many comments and Comment has reference to User (:author). Now when I go to the post page, I expect to see post body + all comments (and their respective authors names). This requires following 2 queries: select * from Post -- to get post data (1 row) select * from Comment inner join User -- to get comment + usernames (N rows) In the code I have: Post.find(params[:id], :include => { :comments => [:author] } But it doesn't work as expected: as I see in the back end, there're still N+1 hits (some of them are cached though). How can I optimize that?

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  • Display rows from MySQL where a datetime is within the next hour

    - by alex
    I always have trouble with complicated SQL queries. This is what I have $query = ' SELECT id, name, info, date_time FROM acms_events WHERE date_time = DATE_SUB(NOW(), INTERVAL 1 HOUR) AND active = 1 ORDER BY date_time ASC LIMIT 6 '; I want to get up to 6 rows that are upcoming within the hour. Is my query wrong? It does not seem to get events that are upcoming within the next hour when I test it. What is the correct syntax for this? Thanks

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  • Designing a table to store EXIF data

    - by rafale
    I'm looking to get the best performance out of querying a table containing EXIF data. The queries in question will only search the EXIF data for the specified strings and return the row index on a match. With that said, would it better to store the EXIF data in a table with separate columns for each of the tags, or would storing all of the tags in a single column as one long delimited string suit me just as well? There are around 115 EXIF tags I'll be storing, and each record would be around 1500 to 2000 chars in length if concatenated into a single string.

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  • Which is quicker? Memcache or file query? (using maxmind geoip.dat file)

    - by tomcritchlow
    Hi, I'm using Python on Appengine and am looking up the geolocation of an IP address like this: import pygeoip gi = pygeoip.GeoIP('GeoIP.dat') Location = gi.country_code_by_addr(self.request.remote_addr) (pygeoip can be found here: http://code.google.com/p/pygeoip/) I want to geolocate each page of my app for a user so currently I lookup the IP address once then store it in memcache. My question - which is quicker? Looking up the IP address each time from the .dat file or fetching it from memcache? Are there any other pros/cons I need to be aware of? For general queries like this, is there a good guide to teach me how to optimise my code and run speed tests myself? I'm new to python and coding in general so apologies if this is a basic concept. Thanks! Tom

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  • How to limit the number of connections to a SQL Server server from my tomcat deployed java applicati

    - by CJ
    I have an application that is deployed on tomcat on server A and sends queries to a huge variety of SQL Server databases on an server B. I am concerned that my application could overload this SQL Server database server and would like some way to preventing it making requests to connect to any database on that server if some arbitrary number of connections were already in existence and unclosed. I am looking at using connection pooling but am under the impression that this will only pool connections to a specific database on the SQL Server server, I want to control the total of these combined connections that will occur to many different databases (incidentally I can only find out the names of individual db's dynamically as they change day to day). Will connection pooling take care of this for me, are am I looking at this from the wrong perspective? I have no access to the configuration of the SQL Server server. Links to tutorials or working examples of your suggested solution are most welcome!

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  • what this `^` mean here in solr

    - by Rahul Mehta
    I am confuse her but i want to clear my doubt. I think it is stupid question but i want to know. Use a TokenFilter that outputs two tokens (one original and one lowercased) for each input token. For queries, the client would need to expand any search terms containing upper case characters to two terms, one lowercased and one original. The original search term may be given a boost, although it may not be necessary given that a match on both terms will produce a higher score. text:NeXT ==> (text:NeXT^10 OR text:next) what this ^ mean here . http://wiki.apache.org/solr/SolrRelevancyCookbook#Relevancy_and_Case_Matching

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  • Could someone give me their two cents on this optimization strategy

    - by jimstandard
    Background: I am writing a matching script in python that will match records of a transaction in one database to names of customers in another database. The complexity is that names are not unique and can be represented multiple different ways from transaction to transaction. Rather than doing multiple queries on the database (which is pretty slow) would it be faster to get all of the records where the last name (which in this case we will say never changes) is "Smith" and then have all of those records loaded into memory as you go though each looking for matches for a specific "John Smith" using various data points. Would this be faster, is it feasible in python, and if so does anyone have any recommendations for how to do it?

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  • Business and data layer in ASP.NET MVC

    - by Shetty
    Hi, I am new to ASP.net MVC architecture. I have read in some articles that Model will contain business and data access logic. So does this mean that i have to implement the business and data access layrers in side model folder? And it is obviously not possible to add class libraries (business layer and Data access layer of n tier) in Model folder. SO please let me know how to design business and data layer if i dont want to include my LINQ queries in Controller. Thanks, Amith

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  • Dynamic query to immediate execute?

    - by Curtis White
    I am using the MSDN Dynamic linq to sql package. It allows using strings for queries. But, the returned type is an IQueryable and not an IQueryable<T>. I do not have the ToList() method. How can I this immediate execute without manually enumerating over the IQueryable? My goal is to databind to the Selecting event on a linqtosql datasource and that throws a datacontext disposed exception. I can set the query as the Datasource on a gridview though. Any help greatly appreciated! Thanks. The dynamic linq to sql is the one from the samples that comes with visual studio.

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  • Inheritance in kohana

    - by Binaryrespawn
    Hi all, I have recently started to use Kohana and I know inheritance is in infancy stages at the moment. The work around is using a $_has_one annotation on the child class model. In may case i have "page" as the parent of "article". I have something like, protected $_has_one = array('mypage'=>array('model'=>'page', 'foreign_key'=>'id')); In my controller, I have an action which queries the database. In this query I am trying to access fields form the parent of "article" which is the "page". $n->articles=ORM::factory('article')->where('expires','=',0) ->where('articledate','<',date('y-m-d')) ->where('expirydate','>',date('y-m-d')) ->where('mypage->status','=','PUBLISHED') ->order_by('articledate','desc') ->find_all(); The status column resides in the page table and my query is generating an error to the effect of "cannot find status", clearly because it belongs to the parent. Any ideas ?

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  • PostgreSQL: How to index all foreign keys?

    - by biggusjimmus
    I am working with a large PostgreSQL database, and I are trying to tune it to get more performance. Our queries and updates seem to be doing a lot of lookups using foreign keys. What I would like is a relatively simple way to add Indexes to all of our foreign keys without having to go through every table (~140) and doing it manually. In researching this, I've come to find that there is no way to have Postgres do this for you automatically (like MySQL does), but I would be happy to hear otherwise there, too.

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  • Beginner, learning as I go - how to get C#/SQLite db set up and ready for testing?

    - by ChrisC
    I've messed with Access a little bit in the past, had one class on OO theory, and one class on console c++ apps. Now, as a hobby project, I'm undertaking to write an actual app, which will be a database app using System.Data.SQLite and C#. I have the db's table structure planned. I have System.Data.SQLite installed and connected to VS Pro. I entered my tables and columns in VS, but that's where I'm stuck. I really don't know how to finish the db set up so I can start creating queries and testing the db structure. Can someone give me guidance to online resources that will help me learn how to get the db properly set up so I can proceed with testing it? I'm hoping for online resources specific to beginners using C# and System.Data.SQLite, but I'll use the closest I can get. Thanks.

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  • JPA in distributed Java EE configuration

    - by sof
    Hello, I'm developing a JEE application to run on Glassfish: Database (javaDB, MS SQL, MySQL or Oracle) EJB layer with JPA (Toplink essentials - from Glassfish) for database access JSF/Icefaces based web UI accessing the EJB layer The application will have a lot of concurrent web client, so I want to run it on different physical servers and use a load-balancer. My problem is now how to keep the applications synchronized. I intend to set up multiple servers, each running Glassfish with my EAR app installed. Whenever on one of the servers data is added to or removed from the database (via JPA, no direct SQL queries), this change should be reflected in the JPA layer on the other servers. I've been looking around for solutions to this, but couldn't find anything I really like (the full Toplink from Oracle claims to have a solution, but don't know). Doing a refresh before every access to a JPA entity could work, but is far from efficient. Are there any patterns, libraries, ... that could help here? Thanks a lot!

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  • Using multiple databases within one application

    - by Alex
    I have a web application made for several groups of people not connected with each other. Instead of using one database for all of them, I'm thinking about making separate databases. This will improve the speed of the queries and make me free from checking to what group the user belongs. But since I'm working with LINQ to SQL, my classes are explicitly connected with the databases, so I will have to make separate DataContexts for all of the databases. So how can I solve this problem? Or should I just not bother and use one database only?

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  • bulk update/delete entities of different kind in db.run_in_transaction

    - by Ray Yun
    Here goes pseudo code of bulk update/delete entities of different kind in single transaction. Note that Album and Song entities have AlbumGroup as root entity. class AlbumGroup: pass class Album: group = db.ReferenceProperty(reference_class=AlbumGroup,collection_name="albums") class Song: album = db.ReferenceProperty(reference_class=Album,collection_name="songs") def bulk_update_album_group(album_group): updated = [album_group] deleted = [] for album in album_group.albums: updated.append(album) for song in album.songs: if song.is_updated: updated.append(song) if song.is_deleted: deleted.append(song) db.put(updated) db.delete(deleted) a = AlbumGroup.all().filter("...").get() # bulk update/delete album group. for simplicity, album cannot be deleted. db.run_in_transaction(bulk_update_album_group,a) But I met a famous "Only Ancestor Queries in Transactions" error at the iterating reference properties like album.songs or album_group.albums. I guess ancestor() filter does not help because those entities are modified in memory. Should I not to iterate reference property in transaction function and always provide them as function parameters like def bulk_update_album_group(updated,deleted): ??? Is there any good coding pattern for this situation?

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  • Does normalization really hurt performance in high traffic sites?

    - by Luke101
    I am designing a database and I would like to normalize the database. I one query I will joining about 30-40 tables. Will this hurt the website performance if it ever becomes extremely popular? This will be the main query and it will be getting called 50% of the time. The other queries I will be joining about 2 tables. I have a choice right now to normalize or not to normalize but if the normalization becomes a problem in the future i may have to rewrite 40% of the software and it may take me a long time. Does normalization really hurt in this case? Should I denormalize now while I have the time?

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  • CakePHP hasOne ineffeciency?

    - by Andre
    I was looking at examples on the CakePHP website, in particular hasOne used in linking models. http://book.cakephp.org/view/78/Associations-Linking-Models-Together My question is this, is CakePHP using two queries to build the array structure of data returned in a model that uses hasOne linkage? Taken from CakePHP: //Sample results from a $this-User-find() call. Array ( [User] => Array ( [id] => 121 [name] => Gwoo the Kungwoo [created] => 2007-05-01 10:31:01 ) [Profile] => Array ( [id] => 12 [user_id] => 121 [skill] => Baking Cakes [created] => 2007-05-01 10:31:01 ) ) Hope this all makes sense.

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  • checking boolean property in XML(Spring)

    - by Abhishek Bhandari
    I am using Spring Framework . While writing coustum SQL queries , i am unable check a parameter of boolean value. For example this is not working .. do some SQl cods The above checking is not working , it is evaluating as equal in both the cases when booleanVariable is true and false . i tried to replace compareValue ="tree" and "false". As that is a monkey work i do sometimes . is it possible to check the boolean property in XML like above .

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  • MySQL : delete from table that is used in the where clause

    - by Eric
    I am writing a small script to synchronize 2 MySQL tables ( t1 to be 'mirrored' to t2 ) In a step I would like to delete rows inside t2 that has been delete in t1 with the same id. I tried this query : delete from t2 where t2.id in ( select t2.id left join t1 on (t1.id=t2.id) where t1.id is null ) But Mysql forbid me to use t2 in the same time in the delete and in the select (sound logical by the way) Of course, I can split the query into 2 queries : first select IDs, then delete rows with these IDs. My question : do you have a cleaner way to delete row from t2 that does not exist anymore in t1 ? with one query only ?

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  • How To Configure Query Cacheing in EclipseLink

    - by rustyshelf
    I have a collection of states, that I want to cache for the life of the application, preferably after it is called for the first time. I'm using EclipseLink as my persistence provider. In my EJB3 entity I have the following code: @Cache @NamedQueries({ @NamedQuery( name = "State.findAll", query = "SELECT s FROM State s", hints = { @QueryHint(name=QueryHints.CACHE_USAGE, value=CacheUsage.CheckCacheThenDatabase), @QueryHint(name=QueryHints.READ_ONLY, value=HintValues.TRUE) } ) }) This doesn't seem to do anything though, if I monitor the SQL queries going to MySQL it still does a select each time my Session Bean uses this NamedQuery. What is the correct way to configure this query so that it is only ever read once from the database, preferably across all sessions? Edit: I am calling the query like this: Query query = em.createNamedQuery("State.findAll"); List<State> states = query.getResultList();

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  • Silverlight - Timeout Issue

    - by user70192
    Hello, I have a Silverlight 3 application that is querying a large dataset. This query is taking over one minute. After approx. one minute into the attempt, an error is getting logged into the event viewer that says: "Membership credential verification failed" Oddly queries that are taking shorter than 1 minute are running successfully. Because of this, I do not believe it is a "credential" issue, unless somehow it is expiring. But how do I set the expiration? I have no idea what else this could be. Thank you,

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  • CakePHP model useTable with SQL Views

    - by Chris
    I'm in the process converting our CakePHP-built website from Pervasive to SQL Server 2005. After a lot of hassle the setup I've gotten to work is using the ADODB driver with 'connect' as odbc_mssql. This connects to our database and builds the SQL queries just fine. However, here's the rub: one of our Models was associated with an SQL view in Pervasive. I ported over the view, but it appears using the set up that I have that CakePHP can't find the View in SQL Server. Couldn't find much after some Google searches - has anyone else run into a problem like this? Is there a solution/workaround, or is there some redesign in my future?

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  • Oracle (Old?) Joins - A tool for conversion?

    - by Grasper
    I have been porting oracle selects, and I have been running across a lot of queries like so: SELECT e.last_name, d.department_name FROM employees e, departments d WHERE e.department_id(+) = d.department_id; ...and: SELECT last_name, d.department_id FROM employees e, departments d WHERE e.department_id = d.department_id(+); Are there any guides/tutorials for converting all of the variants of the (+) syntax? What is that syntax even called (so I can scour google)? Even better.. Is there a tool that will do this conversion for me? When was this standard phased out? Any info is appreciated.

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  • Tips for improving performance of DB that is above size 40 GB (Sql Server 2005) and growing monthly

    - by HotTester
    The current DB or our project has crossed over 40 GB this month and on an average it is growing monthly by around 3 GB. Now all the tables are best normalized and proper indexing has been used. But still as the size is growing it is taking more time to fire even basic queries like 'select count(1) from table'. So can u share some more points that will help in this front. Database is Sql Server 2005. Further if we implement Partitioning wouldn't it create a overhead ? Thanks in advance.

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