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• How to implement message queuing and handling in AWS with NServiceBus

  - by Pete Lunenfeld

  I am creating a new ASP MVC order application in the Amazon (AWS) cloud with the persistence layer at my local datacenter. I will be using the CQRS pattern. The goal of the project is high availability using Queue(s) to store and forward writes (commands/events) that can be picked up and handled asynchronously at my local datacenter. Then, ff the WAN or my local datacenter fails, my cloud MVC app can still take orders and just queue them up until processing can resume. My first thought was to use AWS SQS for the queuing and create my own queue consumer/dispatcher/handler in my own c# application to process the incoming messages/events. MVC (@ Amazon) -- Event/POCO -- SQS -- QueueReader (@ my datacenter) -- DB Then I found NServiceBus. NSB seems to handle lots of details very nicely: message handling, retries, error handling, etc. I hate to reinvent the wheel, and NServiceBus seems like a full featured and mature product that would be perfect for me. But on further research, it does NOT look like NServiceBus is really meant to be used over the WAN in physically separated environments (Cloud to my Datacenter). Google and SO don't really paint a good picture of using NServiceBus across the WAN like I need. How can I use NServiceBus across the WAN? Or is there a better solution to handle queuing and message handling between Amazon an my local datacenter?

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• SQL Databases and table design/organization

  - by John McMullen

  (NOOB disclaimer) I'm working on a system (a type of map), that is accessed mostly via 3 fields: ID (auto incremented), X coordinate, and Y coordinate. As it is right now, i have all data on the map, stored in 1 table. Whenever the map display is loaded it simply queries the database for contents in x and y, and the DB gives the data (other fields in the same entry). If an item on the map is doing something, it has a flag saying its doing something, and then has an ID of the action in another table holding that type of 'actions'. Essentially, for all map data, its stored in 1 table. All actions of a certain type are stored in their own table. I'm a noob, and i'm wondering what the most effective/efficient structure for such a design? (a map that has items, and each item has stats/actions). I'm using PHP atm, using standard SQL queries to get my data. Should i split up the tables so that there are only x number of entries on a table? (coord range limits)? Should it just keep growing and growing? There's a lot of queries to the table... so just tryin to see what is best :/

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• For a set of sql-queries, how do you determine which result-set contains a certain row?

  - by ManBugra

  I have a set of sql - queries: List<String> queries = ... queries[0] = "select id from person where ..."; ... queries[8756] = "select id from person where ..."; Each query selects rows from the same table 'person'. The only difference is the where-clause. Table 'person' looks like this: id | name | ... many other columns How can i determine which queries will contain a certain person in their subset? For example: List<Integer> matchingQueries = magicMethod(queries, [23,45]); The list obtained by 'magicMethod' filters all sql queries present in the list 'queries' (defined above) and returns only those that contain either the person with id 23 OR a person with id 45. Why i need it: I am dealing with an application that contains products and categories where the categories are sql queries that define which products belong to them (queries stored in a table also). Now i have a requirement where an admin has to see all categories an item belongs to immediately after the item was created. Btw, over 8.000 categories defined (so far, more to come). language and db: java && postgreSQL Thanks,

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• Hibernate saveorUpdate method problem

  - by umesh awasthi

  Hi all, i am trying to work on with Hibernate (Database side for first time) and some how struck in choosing best possible way to use saveOrUpdate or Save.Update i have a destination POJO class and its other attributes which needs to be updated along with the Destination entity. i am getting an XML file to be imported and i am using the following code to update/save the destination entity along with its attribute classes. try{ getSessionFactory().getCurrentSession().beginTransaction(); getSessionFactory().getCurrentSession().saveOrUpdate(entity); getSessionFactory().getCurrentSession().getTransaction().commit(); } catch(Exception e){ getSessionFactory().getCurrentSession().getTransaction().rollback(); } finally{ getSessionFactory().close(); } everything is working fine untill i am using the same session instance.but later on when i am using the same XML file to update the destination PO for certain attributes it giving me the following error. SEVERE: Duplicate entry 'MNLI' for key 'DESTINATIONID' 9 Jan, 2011 4:58:11 PM org.hibernate.event.def.AbstractFlushingEventListener performExecutions SEVERE: Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275) at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:114) at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:109) at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:244) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2242) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2678) at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79) i am using UUID as primary key for the Destination table and in destination table i have a destination id which is unique.but i can understand that in the secodn case hibernate is not able to find if there is already an entry for the same destination in the DB and trying to execute insert statement rather than update. one possible solution is i can user destinationid to check if there is already a destination inplace with the given id and based on the results i can issue save or update command. my question is can this be achieve by any other good way..? Thanks in advance

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• Ajax request gets to server but page doesn't update - Rails, jQuery

  - by Jesse

  So I have a scenario where my jQuery ajax request is hitting the server, but the page won't update. I'm stumped... Here's the ajax request: $.ajax({ type: 'GET', url: '/jsrender', data: "id=" + $.fragment().nav.replace("_link", "") }); Watching the rails logs, I get the following: Processing ProductsController#jsrender (for 127.0.0.1 at 2010-03-17 23:07:35) [GET] Parameters: {"action"=>"jsrender", "id"=>"products", "controller"=>"products"} ... Rendering products/jsrender.rjs Completed in 651ms (View: 608, DB: 17) | 200 OK [http://localhost/jsrender?id=products] So, it seems apparent to me that the ajax request is getting to the server. The code in the jsrender method is being executed, but the code in the jsrender.rjs doesn't fire. Here's the method, jsrender: def jsrender @currentview = "shared/#{params[:id]}" respond_to do |format| format.js {render :template => 'products/jsrender.rjs'} end end For the sake of argument, the code in jsrender.rjs is: page<<"alert('this works!');" Why is this? I see in the params that there is no authenticity_token, but I have tried passing an authenticity_token as well with the same result. Thanks in advance.

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• Why does Rails screw up timezones when I am editing a resource?

  - by DJTripleThreat

  Steps to produce this: prompt>rails test_app prompt>cd test_app prompt>script/generate scaffold date_test my_date:datetime prompt>rake db:migrate now edit your app/views/date_tests/edit.html.erb: <h1>Editing date_test</h1> <% form_for(@date_test) do |f| %> <%= f.error_messages %> <p> RIGHT!<br/> <%= text_field_tag @date_test, f.object.my_date %> </p> <p> WRONG!<br /> <%= f.text_field :my_date %> </p> <p> <%= f.submit 'Update' %> </p> <% end %> <%= link_to 'Show', @date_test %> | <%= link_to 'Back', date_tests_path %> now edit your config/environment.rb: #add this config.time_zone = 'Central Time (US & Canada)' This recreates the problem I am having in my actual app. The problem with my app is that I'm storing a date in a hidden field and rendering a "user friendly" version. Creating a resource works fine but as soon as I try to edit it the time changes (it adds the difference between my current time zone configuration and UTC). go to http://localhost:3000/date_tests/new and save the time then go to reedit it and you will have two different representations of the date/time one which will save incorrectly and the other that will.

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• PHP OOP: Avoid Singleton/Static Methods in Domain Model Pattern

  - by sunwukung

  I understand the importance of Dependency Injection and its role in Unit testing, which is why the following issue is giving me pause: One area where I struggle not to use the Singleton is the Identity Map/Unit of Work pattern (Which keeps tabs on Domain Object state). //Not actual code, but it should demonstrate the point class Monitor{//singleton construction omitted for brevity static $members = array();//keeps record of all objects static $dirty = array();//keeps record of all modified objects static $clean = array();//keeps record of all clean objects } class Mapper{//queries database, maps values to object fields public function find($id){ if(isset(Monitor::members[$id]){ return Monitor::members[$id]; } $values = $this->selectStmt($id); //field mapping process omitted for brevity $Object = new Object($values); Monitor::new[$id]=$Object return $Object; } $User = $UserMapper->find(1);//domain object is registered in Id Map $User->changePropertyX();//object is marked "dirty" in UoW // at this point, I can save by passing the Domain Object back to the Mapper $UserMapper->save($User);//object is marked clean in UoW //but a nicer API would be something like this $User->save(); //but if I want to do this - it has to make a call to the mapper/db somehow $User->getBlogPosts(); //or else have to generate specific collection/object graphing methods in the mapper $UserPosts = $UserMapper->getBlogPosts(); $User->setPosts($UserPosts); Any advice on how you might handle this situation? I would be loathe to pass/generate instances of the mapper/database access into the Domain Object itself to satisfy DI - At the same time, avoiding that results in lots of calls within the Domain Object to external static methods. Although I guess if I want "save" to be part of its behaviour then a facility to do so is required in its construction. Perhaps it's a problem with responsibility, the Domain Object shouldn't be burdened with saving. It's just quite a neat feature from the Active Record pattern - it would be nice to implement it in some way.

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• Should I use a regular server instead of AWS?

  - by Jon Ramvi

  Reading about and using the Amazon Web Services, I'm not really able to grasp how to use it correctly. Sorry about the long question: I have a EC2 instance which mostly does the work of a web server (apache for file sharing and Tomcat with Play Framework for the web app). As it's a web server, the instance is running 24/7. It just came to my attention that the data on the EC2 instance is non persistent. This means I lose my database and files if it's stopped. But I guess it also means my server settings and installed applications are lost as they are just files in the same way as the other data. This means that I will either have to rewrite the whole app to use amazon CloudDB or write some code which stores the db on S3 and make my own AMI with the correct applications installed and configured. Or can this be quick-fixed by using EBS somehow? My question is 1. is my understanding of aws is correct? and 2. is it's worth it? It could be a possibility to just set up a regular dedicated server where everything is persistent, as you would expect. Would love to have the scaleability of aws though..

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• Strange JPA one-to-many behavior when trying to set the "many" on the "one" entity

  - by errr

  I've mapped two entities using JPA (specifically Hibernate). Those entities have a one-to-many relationship (I've simplified for presentation): @Entity public class A { @ManyToOne public B getB() { return b; } } @Entity public Class B { @OneToMany(mappedBy="b") public Set<A> getAs() { return as; } } Now, I'm trying to create a relationship between two instances of these entities by using the setter of the one-side/not-owner-side of the relationship (i.e the table being referenced to): em.getTransaction().begin(); A a = new A(); B b = new B(); Set<A> as = new HashSet<A>(); as.add(a); b.setAs(as); em.persist(a); em.persist(b); em.getTransaction().commit(); But then, the relationship isn't persisted to the DB (the row created for entity A isn't referencing the row created for entity B). Why is it so? I'd excpect it to work. Also, if I remove the "mappedBy" property from the @OneToMany annotation it will work. Again - why is it so? and what are the possible effects for removing the "mappedBy" property?

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• If we make a number every millisecond, how much data would we have in a day?

  - by Roger Travis

  I'm a bit confused here... I'm being offered to get into a project, where would be an array of certain sensors, that would give off reading every millisecond ( yes, 1000 reading in a second ). Reading would be a 3 or 4 digit number, for example like 818 or 1529. This reading need to be stored in a database on a server and accessed remotely. I never worked with such big amounts of data, what do you think, how much in terms of MBs reading from one sensor for a day would be?... 4(digits)x1000x60x60x24 ... = 345600000 bits ... right ? about 42 MB per day... doesn't seem too bad, right? therefor a DB of, say, 1 GB, would hold 23 days of info from 1 sensor, correct? I understand that MySQL & PHP probably would not be able to handle it... what would you suggest, maybe some aps? azure? oracle? ... Thansk!

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• django: results in in_bulk style without IDs

  - by valya

  in django 1.1.1, Place.objects.in_bulk() does not work and Place.objects.in_bulk(range(1, 100)) works and returns a dictionary of Ints to Places with indexes - primary keys. How to avoid using range in this situation (and avoid using a special query for ids, I just want to get all objects in this dictionary format) >>> Place.objects.in_bulk() Traceback (most recent call last): File "<console>", line 1, in <module> File "/usr/lib/python2.5/site-packages/Django-1.1.1-py2.5.egg/django/db/models/manager.py", line 144, in in_bulk return self.get_query_set().in_bulk(*args, **kwargs) TypeError: in_bulk() takes exactly 2 arguments (1 given) >>> Place.objects.in_bulk(range(1, 100)) {1L: <Place: "??? ????">, 3L: <Place: "???????????? ?????">, 4L: <Place: "????????? "??????"">, 5L: <Place: "????????? "??????"">, 8L: <Place: "????????? "??????????????"">, 9L: <Place: "??????? ????????">, 10L: <Place: "????????? ???????">, 11L: <Place: "??????????????? ???">, 14L: <Place: "????? ????? ??????">}

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• What is the difference between Unidirectional and Bidirectional associations?

  - by hguser

  Hi: What is the difference between Unidirectional and Bidirectional associations? Since the table generated in the db are all the same,so the only difference I found is that each side of the bidiretional assocations will have a refer to the other,and the unidirectional not. /////////// This is a Unidirectional association public class User { private int id; private String name; @ManyToOne @JoinColumn( name = "groupId") private Group group; } public class Group { private int id; private String name; } ////////////// The Bidirectional association public class User { private int id; private String name; @ManyToOne @JoinColumn( name = "groupId") private Group group; } public class Group { private int id; private String name; @OneToMany(mappedBy="group") private List<User> users; } The difference is wheather the group hold a refer of the user. So I wonder if this is the only difference? which is recommended?

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• Passing jquery JSON from Codeigniter controller to view

  - by dede

  I've been struggling to make it work, but cannot pass the inserted data from the controler to the view in CI using JSON. The input value from the form is successfully inserted into the database, but cannot make it appear in the view. This is my view file ajax_view.php: <script type="text/javascript" src="<?php echo base_url(); ?>js/jquery-1.4.2.min.js"></script> $(document).ready(function(){ $("#submit").click(function(){ var inp = $('#inp').val(); $.post("ajax/ajax_input", { 'send' : inp }, function(data){ alert(data.input_text); }, "json"); }); }); </script> </head> <body> <form id="form1" method="post" action=""> <label for="inp">Text</label> <input type="text" name="inp" id="inp" /> <label for="submit"></label> <input type="submit" name="submit" id="submit" value="Submit" /> And this is the ajax_input method of the ajax.php controller: <?php // Initializing controller ..... // ............................. //ajax method function ajax_input(){ $var_1 = trim($this->input->post('send')); $array = array('input_text' => $var_1); echo json_encode($array); $this->db->insert('ajax',$array); } Trying to debug it with Firebug, it gives me that data.input_text is empty. What am I doing wrong? EDIT: I'm using XAMPP on Win, so is it posible that json configuration is the problem?

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• Spring Security ACL: NotFoundException from JDBCMutableAclService.createAcl

  - by user340202

  Hello, I've been working on this task for too long to abandon the idea of using Spring Security to achieve it, but I wish that the community will provide with some support that will help reduce the regret that I have for choosing Spring Security. Enough ranting and now let's get to the point. I'm trying to create an ACL by using JDBCMutableAclService.createAcl as follows: [code] public void addPermission(IWFArtifact securedObject, Sid recipient, Permission permission, Class clazz) { ObjectIdentity oid = new ObjectIdentityImpl(clazz.getCanonicalName(), securedObject.getId()); this.addPermission(oid, recipient, permission); } @Override @Transactional(propagation = Propagation.REQUIRED, isolation = Isolation.READ_UNCOMMITTED, readOnly = false) public void addPermission(ObjectIdentity oid, Sid recipient, Permission permission) { SpringSecurityUtils.assureThreadLocalAuthSet(); MutableAcl acl; try { acl = this.mutableAclService.createAcl(oid); } catch (AlreadyExistsException e) { acl = (MutableAcl) this.mutableAclService.readAclById(oid); } // try { // acl = (MutableAcl) this.mutableAclService.readAclById(oid); // } catch (NotFoundException nfe) { // acl = this.mutableAclService.createAcl(oid); // } acl.insertAce(acl.getEntries().length, permission, recipient, true); this.mutableAclService.updateAcl(acl); } [/code] The call throws a NotFoundException from the line: [code] // Retrieve the ACL via superclass (ensures cache registration, proper retrieval etc) Acl acl = readAclById(objectIdentity); [/code] I believe this is caused by something related to Transactional, and that's why I have tested with many TransactionDefinition attributes. I have also doubted the annotation and tried with declarative transaction definition, but still with no luck. One important point is that I have used the statement used to insert the oid in the database earlier in the method directly on the database and it worked, and also threw a unique constraint exception at me when it tried to insert it in the method. I'm using Spring Security 2.0.8 and IceFaces 1.8 (which doesn't support spring 3.0 but definetely supprorts 2.0.x, specially when I keep caling SpringSecurityUtils.assureThreadLocalAuthSet()). My AppServer is Tomcat 6.0, and my DB Server is MySQL 6.0 I wish to get back a reply soon because I need to get this task off my way

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• php request variables assigning $_GEt

  - by chris

  if you take a look at a previous question http://stackoverflow.com/questions/2690742/mod-rewrite-title-slugs-and-htaccess I am using the solution that Col. Shrapnel proposed- but when i assign values to $_GET in the actual file and not from a request the code doesnt work. It defaults away from the file as if the $_GET variables are not set The code I have come up with is- if(!empty($_GET['cat'])){ $_GET['target'] = "category"; if(isset($_GET['page'])){ $_GET['pageID'] = $_GET['page']; } $URL_query = "SELECT category_id FROM cats WHERE slug = '".$_GET['cat']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); $_GET['category_id'] = $URL_array['category_id']; }elseif($_GET['product']){ $_GET['target'] = "product"; $URL_query = "SELECT product_id FROM products WHERE slug = '".$_GET['product']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); print_r($URL_array); $_GET['product_id'] = $URL_array['product_id']; The original variable string that im trying to represent is /cart.php?Target=product&product_id=16142&category_id=249 And i'm trying to build the query string variables with code and including cart.php so i can use cleaner URL's So I have product/product-title-with-clean-url/ going to slug.php?product=slug Then the slug searches the db for a record with the matching slug and returns the product_id as in the code above.Then built the query string and include cart.php

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• Long running method causing race condition

  - by keeleyt83

  Hi, I'm relatively new with hibernate so please be gentle. I'm having an issue with a long running method (~2 min long) and changing the value of a status field on an object stored in the DB. The pseudo-code below should help explain my issue. public foo(thing) { if (thing.getStatus() == "ready") { thing.setStatus("finished"); doSomethingAndTakeALongTime(); } else { // Thing already has a status of finished. Send the user back a message. } } The pseudo-code shouldn't take much explanation. I want doSomethingAndTakeALongTime() to run, but only if it has a status of "ready". My issue arises whenever it takes 2 minutes for doSomethingAndTakeALongTime() to finish and the change to thing's status field doesn't get persisted to the database until it leaves foo(). So another user can put in a request during those 2 minutes and the if statement will evaluate to true. I've already tried updating the field and flushing the session manually, but it didn't seem to work. I'm not sure what to do from here and would appreciate any help. PS: My hibernate session is managed by spring.

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• How to use AFIncrementalStore to binding with a NSManagedObject

  - by Matrosov Alexander

  I am searching for more information on how to use AFIncrementalStore. I need to know how to implement it step by step. Please don't down vote it, because of many resources, I really need help with this. If I understood right AFIncrementalStore it is a layer for fetching data from the server and for the mapping data model. Am I right? So I have few URL that I need to mapping into my local model. All of them use GET requests. For example base_url/api/categories I get this string in response: [{"category":{"name":"3d max","id":"1111001","users":[]}}, {"category":{"name":"photoshop","id":"1111002","users":[]}}, {"category":{"name":"auto cad","id":"1111003","users":[]}}] So I have a question how I can binding my local db with this data using AFIncrementalStore. Also if you can see there are relationships in the response string that are connected to uses. The array for users will contain id that is correspond to concert users. So I think second question is how to point that model has to have relationship.

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• Locating SSL certificate, key and CA on server

  - by jovan

  Disclaimer: you don't need to know Node to answer this question but it would help. I have a Node server and I need to make it work with HTTPS. As I researched around the internet, I found that I have to do something like this: var fs = require('fs'); var credentials = { key: fs.readFileSync('path/to/ssl/private-key'), cert: fs.readFileSync('path/to/ssl/cert'), ca: fs.readFileSync('path/to/something/called/CA') }; var app = require('https').createServer(credentials, handler); I have several problems with this. First off, all the examples I found use completely different approaches. Some link to .pem files for both the certificate and key. I don't know what pem files are but I know my certificate is .crt and my key is .key. Some start off at the root folder and some seem to just have these .pem files in the application directory. I don't. Some use the ca thing too and some don't. This CA is supposed to be my domain's CA bundle according to some articles - but none explain where to find this file. In the ssl directory on my server I have one .crt file in the certs directory and one .key file in the keys directory, in addition to an empty csrs directory and an ssl.db file. So, where do I find these 3 files (key, cert, ca) and how do I link to them correctly?

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• why does cx_oracle execute() not like my string now?

  - by Frank Stallone

  I've downloaded cx_oracle some time ago and wrote a script to convert data to XML. I've had to reisntall my OS and grabbed the latest version of cx_Oracle (5.0.3) and all of the sudden my code is broken. The first thing was that cx_Oracle.connect wanted unicode rather string for the username and password, that was very easy to fix. But now it keeps failing on the cursor.execute and tells me my string is not a string even when type() tells me it is a string. Here is a test script I initally used ages ago and worked fine on my old version but does not work on cx_Oracle now. import cx_Oracle ip = 'url.to.oracle' port = 1521 SID = 'mysid' dsn_tns = cx_Oracle.makedsn(ip, port, SID) connection = cx_Oracle.connect(u'name', u'pass', dsn_tns) cursor = connection.cursor() cursor.arraysize = 50 sql = "select isbn, title_code from core_isbn where rownum<=20" print type(sql) cursor.execute(sql) for isbn, title_code in cursor.fetchall(): print "Values from DB:", isbn, title_code cursor.close() connection.close() When I run that I get: Traceback (most recent call last): File "C:\NetBeansProjects\Python\src\db_temp.py", line 48, in cursor.execute(sql) TypeError: expecting None or a string Does anyone know what I may be doing wrong?

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• database connection OK,result not appear

  - by klox

  hi..all.for now i'm already connected to database but the result not appear at Tuner range is"+res+"this is my code: var str=data[0]; var matches=str.match(/[EE|EJU].*D/i); $.ajax({ type:"post", url:"process1.php", data:"tversion="+matches+"&action=tunermatches", cache:false, async:false, success: function(res){ $('#value').replacewith("<div id='value'><h6>Tuner range is"+res+".</h6></div>"); } }); }); and this is my process file: //connect to database $dbc=mysql_connect(_SRV,_ACCID,_PWD) or die(_ERROR15.": ".mysql_error()); $db=mysql_select_db("qdbase",$dbc) or die(_ERROR17.": ".mysql_error()); switch(postVar('action')) { case 'tunermatches' : tunermatches(postVar('tversion')); break; function tunermatches($tversion)){ $Tuner=mysql_real_escape_string($tversion); $sql= "SELECT remark FROM settingdata WHERE itemname='Tuner_range' AND itemdata='".$Tunermatches."'"; $res=mysql_query($sql) or die (_ERROR26.":".mysql_error()); $dat=mysql_fetch_array($res,MYSQL_NUM); if($dat[0]>0) { echo $dat[0]; } mysql_close($dbc); }

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• How to make write operation idempotent?

  - by Morgan Cheng

  I'm reading article about recently release Gizzard sharding framework by twitter(http://engineering.twitter.com/2010/04/introducing-gizzard-framework-for.html). It mentions that all write operations must be idempotent to make sure high reliability. According to wikipedia, "Idempotent operations are operations that can be applied multiple times without changing the result." But, IMHO, in Gazzard case, idempotent write operation should be operations that sequence doesn't matter. Now, my question is: How to make write operation idempotent? The only thing I can image is to have a version number attached to each write. For example, in blog system. Each blog must have a $blog_id and $content. In application level, we always write a blog content like this write($blog_id, $content, $version). The $version is determined to be unique in application level. So, if application first try to set one blog to "Hello world" and second want it to be "Goodbye", the write is idempotent. We have such two write operations: write($blog_id, "Hello world", 1); write($blog_id, "Goodbye", 2); These two operations are supposed to changed two different records in DB. So, no matter how many times and what sequence these two operations executed, the results are same. This is just my understanding. Please correct me if I'm wrong.

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• is there a better way to write this frankenstein LINQ query that searches for values in a child tabl

  - by MRV

  I have a table of Users and a one to many UserSkills table. I need to be able to search for users based on skills. This query takes a list of desired skills and searches for users who have those skills. I want to sort the users based on the number of desired skills they posses. So if a users only has 1 of 3 desired skills he will be further down the list than the user who has 3 of 3 desired skills. I start with my comma separated list of skill IDs that are being searched for: List<short> searchedSkillsRaw = skills.Value.Split(',').Select(i => short.Parse(i)).ToList(); I then filter out only the types of users that are searchable: List<User> users = (from u in db.Users where u.Verified == true && u.Level > 0 && u.Type == 1 && (u.UserDetail.City == city.SelectedValue || u.UserDetail.City == null) select u).ToList(); and then comes the crazy part: var fUsers = from u in users select new { u.Id, u.FirstName, u.LastName, u.UserName, UserPhone = u.UserDetail.Phone, UserSkills = (from uskills in u.UserSkills join skillsJoin in configSkills on uskills.SkillId equals skillsJoin.ValueIdInt into tempSkills from skillsJoin in tempSkills.DefaultIfEmpty() where uskills.UserId == u.Id select new { SkillId = uskills.SkillId, SkillName = skillsJoin.Name, SkillNameFound = searchedSkillsRaw.Contains(uskills.SkillId) }), UserSkillsFound = (from uskills in u.UserSkills where uskills.UserId == u.Id && searchedSkillsRaw.Contains(uskills.SkillId) select uskills.UserId).Count() } into userResults where userResults.UserSkillsFound > 0 orderby userResults.UserSkillsFound descending select userResults; and this works! But it seems super bloated and inefficient to me. Especially the secondary part that counts the number of skills found. Thanks for any advice you can give. --r

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• Saving a list of items in Application State ASP.NET MVC ?

  - by Calibre2010

  Hi Guys, I'm having a bit of trouble with knowing how I can save items from a list I have in Application state in the global.asax as- Application[""]. My controller basically takes in some user input, I then pass this to another classes Method as parameters it gets added to a list all the time. This data thats getting added to the list I want to store it, but without using a db. By using Application State. . I have been instantiating this class and calling its method to return the list of items but I dont think Application State is saving it. Here is what I have so far. . protected void Application_Start() { RegisterRoutes(RouteTable.Routes); TimeLineInformation t = new TimeLineInformation(); IList<SWTimeEnvInfoDTO> g = t.getInfo(); Application["AppID"] = g; } ^ Global.asax IList<SWTimeEnvInfoDTO> result = new List<SWTimeEnvInfoDTO>(); public void returnTimeLineInfo(string SWrelease, string EnvName, DateTime SDate, DateTime EDate) { SWTimeEnvInfoDTO myDTO = new SWTimeEnvInfoDTO(); myDTO.softwareReleaseName = SWrelease; myDTO.environmentName = EnvName; myDTO.StartDate = SDate; myDTO.EndDate = EDate; result.Add(myDTO); getInfo(); } public IList<SWTimeEnvInfoDTO> getInfo() { return result; } ^ class im calling The SWTimeEnvInfoDTO type has get and set methods for the data. I am calling the application from a View as well. It works with a string Application["AppID"] = "fgt"; and shows this once i read it from my view.

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• Advanced search engine or server for relational database [closed]

  - by Pawel

  In my current project we are storing big volume of data in relational database. One of the recent key requirements is to enrich application by adding some advanced search capabilities. In the Project, performance is one of the important factors due to very large tables (10+ milions of records) with parent-children relations (for example: multi-level parent-child relationship, where I am looking for all parents with specific children). The search engine should also be able to check these references for hits. I have found some potential engines on stack overflow, however it looks like that all of them are dedicated rather for text search than relational db and hosted on linux os: lucene Solr Sphinx As I understand some of them use documents as a source of searching, but is it possible or efficient to create programmaticaly documents based on my relational data? As I am not familiar with all of their features/capabilities can anyone please make some recommendations or propose some different solution? To summarize my requirements: framework/engine to search relational database including decendants. support for Microsoft SQL Server can be used in .NET applications preferably hosted on Windows systems Does any of mentioned above are able to solve my problem? do you know any better solution?

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• What is a good approach to preloading data?

  - by Bob Horn

  Are there best practices out there for loading data into a database, to be used with a new installation of an application? For example, for application foo to run, it needs some basic data before it can even be started. I've used a couple options in the past: TSQL for every row that needs to be preloaded: IF NOT EXISTS (SELECT * FROM Master.Site WHERE Name = @SiteName) INSERT INTO [Master].[Site] ([EnterpriseID], [Name], [LastModifiedTime], [LastModifiedUser]) VALUES (@EnterpriseId, @SiteName, GETDATE(), @LastModifiedUser) Another option is a spreadsheet. Each tab represents a table, and data is entered into the spreadsheet as we realize we need it. Then, a program can read this spreadsheet and populate the DB. There are complicating factors, including the relationships between tables. So, it's not as simple as loading tables by themselves. For example, if we create Security.Member rows, then we want to add those members to Security.Role, we need a way of maintaining that relationship. Another factor is that not all databases will be missing this data. Some locations will already have most of the data, and others (that may be new locations around the world), will start from scratch. Any ideas are appreciated.

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