Search Results

Search found 7240 results on 290 pages for 'natural join'.

Page 33/290 | < Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >

  • How to interview a natural scientist for a dev position?

    - by Silas
    I already did some interviews for my company, mostly computer scientists for dev positions but also some testers and project managers. Now I have to fill a vacancy in our research group within the R&D department (side note: “research” means that we try to solve problems in our professional domain/market niche using software in research projects together with universities, other companies, research centres and end user organisations. It’s not computer science research; we’re not going to solve the P=NP problem). Now we invited a guy holding an MSc in chemistry (with a lot of physics in his CV, too), who never had any computer science lesson. I already talked with him about half an hour at a local university’s career days and there’s no doubt the guy is smart. Also his marks are excellent and he graduated with distinction. For his BSc he needed to teach himself programming in Mathematica and told me believably that he liked programming a lot. Also he solved some physical chemistry problem that I probably don’t understand using his own software, implemented in Mathematica, for his MSc thesis. It includes a GUI and a notable size of 8,000 LoC. He seems to be very attracted by what we’re doing in our research group and to be honest it’s quite difficult for an SME like us to get good people. I also am very interested in hiring him since he could assist me in writing project proposals, reports, doing presentations and so on. He would probably fit to our team, too. The only question left is: How can I check if he will get the programming skills he needs to do software implementation in our projects since this will be a significant part of the job? Of course I will ask him what it is, that is fascinating him about programming. I’ll also ask how he proceeded to write his natural science software and how he structured it. I’ll ask about how he managed to obtain the skills and information about software development he needed. But is there something more I could ask? Something more concrete perhaps? Should I ask him to explain his Mathematica solution? To be clear: I’m not looking for knowledge in a particular language or technology stack. We’re a .NET shop in product development but I want to have a free choice for our research projects. So I’m interested in the meta-competence being able to learn whatever is actually needed. I hope this question is answerable and not open-ended since I really like to know if there is a default way to check for the ability to get further programming skills on the job. If something is not clear to you please give me some comments and let me improve my question.

    Read the article

  • Saving a Join Model

    - by Thorpe Obazee
    I've been reading the cookbook for a while now and still don't get how I'm supposed to do this: My original problem was this: A related Model isn't being validated From RabidFire's commment: If you want to count the number of Category models that a new Post is associated with (on save), then you need to do this in the beforeSave function as I've mentioned. As you've currently set up your models, you don't need to use the multiple rule anywhere. If you really, really want to validate against a list of Category IDs for some reason, then create a join model, and validate category_id with the multiple rule there. Now, I have these models and are now validating. The problem now is that data isn't being saved in the Join Table: class Post extends AppModel { var $name = 'Post'; var $hasMany = array( 'CategoryPost' => array( 'className' => 'CategoryPost' ) ); var $belongsTo = array( 'Page' => array( 'className' => 'Page' ) ); class Category extends AppModel { var $name = 'Category'; var $hasMany = array( 'CategoryPost' => array( 'className' => 'CategoryPost' ) ); class CategoryPost extends AppModel { var $name = 'CategoryPost'; var $validate = array( 'category_id' => array( 'rule' => array('multiple', array('in' => array(1, 2, 3, 4))), 'required' => FALSE, 'message' => 'Please select one, two or three options' ) ); var $belongsTo = array( 'Post' => array( 'className' => 'Post' ), 'Category' => array( 'className' => 'Category' ) ); This is the new Form: <div id="content-wrap"> <div id="main"> <h2>Add Post</h2> <?php echo $this->Session->flash();?> <div> <?php echo $this->Form->create('Post'); echo $this->Form->input('Post.title'); echo $this->Form->input('CategoryPost.category_id', array('multiple' => 'checkbox')); echo $this->Form->input('Post.body', array('rows' => '3')); echo $this->Form->input('Page.meta_keywords'); echo $this->Form->input('Page.meta_description'); echo $this->Form->end('Save Post'); ?> </div> <!-- main ends --> </div> The data I am producing from the form is as follows: Array ( [Post] => Array ( [title] => 1234 [body] => 1234 ) [CategoryPost] => Array ( [category_id] => Array ( [0] => 1 [1] => 2 ) ) [Page] => Array ( [meta_keywords] => 1234 [meta_description] => 1234 [title] => 1234 [layout] => index ) ) UPDATE: controller action //Controller action function admin_add() { // pr(Debugger::trace()); $this->set('categories', $this->Post->CategoryPost->Category->find('list')); if ( ! empty($this->data)) { $this->data['Page']['title'] = $this->data['Post']['title']; $this->data['Page']['layout'] = 'index'; debug($this->data); if ($this->Post->saveAll($this->data)) { $this->Session->setFlash('Your post has been saved', 'flash_good'); $this->redirect($this->here); } } } UPDATE #2: Should I just do this manually? The problem is that the join tables doesn't have things saved in it. Is there something I'm missing? UPDATE #3 RabidFire gave me a solution. I already did this before and am quite surprised as so why it didn't work. Thus, me asking here. The reason I think there is something wrong. I don't know where: Post beforeSave: function beforeSave() { if (empty($this->id)) { $this->data[$this->name]['uri'] = $this->getUniqueUrl($this->data[$this->name]['title']); } if (isset($this->data['CategoryPost']['category_id']) && is_array($this->data['CategoryPost']['category_id'])) { echo 'test'; $categoryPosts = array(); foreach ($this->data['CategoryPost']['category_id'] as $categoryId) { $categoryPost = array( 'category_id' => $categoryId ); array_push($categoryPosts, $categoryPost); } $this->data['CategoryPost'] = $categoryPosts; } debug($this->data); // Gives RabidFire's correct array for saving. return true; } My Post action: function admin_add() { // pr(Debugger::trace()); $this->set('categories', $this->Post->CategoryPost->Category->find('list')); if ( ! empty($this->data)) { $this->data['Page']['title'] = $this->data['Post']['title']; $this->data['Page']['layout'] = 'index'; debug($this->data); // First debug is giving the correct array as above. if ($this->Post->saveAll($this->data)) { debug($this->data); // STILL gives the above array. which shouldn't be because of the beforeSave in the Post Model // $this->Session->setFlash('Your post has been saved', 'flash_good'); // $this->redirect($this->here); } } }

    Read the article

  • Join Production Server 2008 to 2003 domain

    - by Campo
    I administer a production server for a .com. It is live right now. Server 2008 x64 IIS 7 SQL 2008 PHP MYSQL I have another server which is a DC Server 2003 x86 and a warm standby for the website, sql, DFS, exchange queue. In order to get DFS going to transfer user photos and other content I need it in the domain. My question is, What preparations do I need to do to the production server to allow a smooth transition onto the domain? Things such as permissions for the website. I do not want to be running around resetting all the permissions. The Group Policy on the DC is completely default. Should I add the DNS manually or allow it to add itself? Anything else I left out.

    Read the article

  • windows 2003 server : can't join domain

    - by phill
    I originally tried to rejoin a computer to a network which led to a "cannot find domain" error. The username/password box don't even come up. some tests i ran: I can ping the server, however I can't ping the domain name domain1.local. nslookup can't find the domain either. It looks to the isp's dns instead of my own to resolve the local machines. So i go to the dns and run netdiag.exe and gives me this error. DNS test . . . . . . . . . . . . . : Failed [WARNING] Cannot find a primary authoritative DNS server for the name 'stmartinsrv.stmartin.local.'. [RCODE_SERVER_FAILURE] The name 'srv.domain1.local.' may not be registered in DNS. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.156.1'. Please wait for 30 minutes for DNS server replication. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.157.1'. Please wait for 30 minutes for DNS server replication. [FATAL] No DNS servers have the DNS records for this DC registered. Redir and Browser test . . . . . . : Passed List of NetBt transports currently bound to the Redir NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The redir is bound to 1 NetBt transport. List of NetBt transports currently bound to the browser NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The browser is bound to 1 NetBt transport. then running dcdiag C:\Program Files\Support Toolsdcdiag Domain Controller Diagnosis Performing initial setup: Done gathering initial info. Doing initial required tests Testing server: Default-First-Site-Name\SRV Starting test: Connectivity The host 1c99f63c-49ec-40db-b3d3-6265c00fbd3e._msdcs.domain1.local cou ld not be resolved to an IP address. Check the DNS server, DHCP, server name, etc Although the Guid DNS name (1c99f63c-49ec-40db-b3d3-6265c00fbd3e._msdcs.domain1.local) couldn't be resolved, the server name (srv.domain1.local) resolved to the IP address (192.168.1.21) and was pingable. Check that the IP address is registered correctly with the DNS server. ......................... SRV failed test Connectivity Doing primary tests Testing server: Default-First-Site-Name\SRV Skipping all tests, because server SRV is not responding to directory service requests Running partition tests on : ForestDnsZones Starting test: CrossRefValidation ......................... ForestDnsZones passed test CrossRefValidation Starting test: CheckSDRefDom ......................... ForestDnsZones passed test CheckSDRefDom Running partition tests on : DomainDnsZones Starting test: CrossRefValidation ......................... DomainDnsZones passed test CrossRefValidation Starting test: CheckSDRefDom ......................... DomainDnsZones passed test CheckSDRefDom Running partition tests on : Schema Starting test: CrossRefValidation ......................... Schema passed test CrossRefValidation Starting test: CheckSDRefDom ......................... Schema passed test CheckSDRefDom Running partition tests on : Configuration Starting test: CrossRefValidation ......................... Configuration passed test CrossRefValidation Starting test: CheckSDRefDom ......................... Configuration passed test CheckSDRefDom Running partition tests on : domain1 Starting test: CrossRefValidation ......................... domain1 passed test CrossRefValidation Starting test: CheckSDRefDom ......................... domain1 passed test CheckSDRefDom Running enterprise tests on : domain1.local Starting test: Intersite ......................... domain1.local passed test Intersite Starting test: FsmoCheck ......................... domain1.local passed test FsmoCheck from previous postings, I've tried adding the domain suffix to the nic ip properties to both the client machine and the dc server which didn't help. note: there is only one nic on the server any ideas? thanks in advance

    Read the article

  • Join ActiveDirectory (Win 2k8R2) to OpenDirectory(Snow Leopard)

    - by Tom O'Connor
    The vast majority of questions and so on regarding the interoperability of Active and Open directories involves getting Mac clients to see an AD and auth against it. What we'd like to do is get a Windows 7 workstation to auth completely against Open Directory. We tried setting it up as an NT4 type PDC, and that doesn't work satisfactorily. We tried using pGina and the LDAP backend, which allows Authentication, but has no support for Authorization, and as a result, if we mount an NFS Share, the user has the rights to do anything they damn well please. Not ideal for security (Totally bloody unacceptable, actually). We tried using a Samba server (newer version than on the Open Directory Server) as an intermediate, so that it knows about the LDAP server on the OD Server, but uses Samba 4 instead of v3. That didn't work either. We could login, but couldn't mount, and if we did, we had the same rights as with pGina. If we right-click the mounted drive in Windows, and have a look at NFS UID, it returns -2, not the correct (mapped) UID. So the final plan I've got is to use an Active Directory, inside a Windows 2008R2 Virtual Machine. What I want to achieve is to have the Active Directory sync it's user data from OpenDirectory (read-only would be fine). That way, we'd have the ability to connect Windows 7 clients to a "virtual domain" which would actually just grab information from OD's LDAP. All the information I've found is about how to go the other way. Does anyone know how we can do this?

    Read the article

  • Join performance on MyISAM and InnoDB tables

    - by j0nes
    I am thinking about converting some tables from MyISAM to InnoDB in my mysql server. The tables will certainly benefit from the change because a lot of write requests come to these tables, while there are also quite a lot of read request at the same time. However, they are often joined together with some tables that almost don't get any writes. Is there a performance penalty when joining together MyISAM and InnoDB tables or should everything work fine? Second question: During backups at night, I am copying data from the InnoDB tables to MyISAM tables for archiving purposes. In these backups, a lot of write-requests happen, however there is almost no read from these archive tables. Would these tables also benefit from using InnoDB or is this just a waste of space and RAM?

    Read the article

  • Merging Two Git Repositories with branches

    - by Joel K
    I realize there's a Stack Overflow question: http://stackoverflow.com/questions/277029/combining-multiple-git-repositories But I haven't found git-stitch-repo to be quite the tool I'm looking for. I also consider this more of a sysadmin task. How do I take code from an external repository and combine it with code from a primary repository while maintaining history/diffs and branches. Use case: An outside development team using SVN has ported to git and now wants to 'merge' their code in to the main company's git repo. I've tried subtree merges, but I lose the history. I've tried git-stitch-repo, but that process results in an entirely new repo that's missing branches. I just want to slot in some outside code as a sub-directory in our current main repo with as little disruption as possible and while maintaining the other project's history. Any success stories out there?

    Read the article

  • Should I join technicians' laptops to our domain?

    - by TooFat
    I have been charged with distributing about a dozen laptops to technicians at our company that will spend almost all of their time in the field not connected to our network. They may come in for quarterly meetings and may or may not connect their laptops to the network. My question is what are the benefits or disadvantages of joining these laptops to our domain and under these circumstances (given what I describe above) what would you do?

    Read the article

  • Should I join technicians laptops tp our domain?

    - by TooFat
    I have been charged with distributing about a dozen laptops to technicians at our company that will spend almost all of their time in the field not connected to our network. They may come in for quarterly meetings and may or may not connect their laptops to the network. My question is what are the benefits or disadvantages of joining these laptops to our domain and under these circumstances (given what I describe above) what would you do?

    Read the article

  • How to conncet(join) host laptop to the guset 2k8 server [closed]

    - by Dawood Said
    Dear brother I have core i5 laptop with wireless ip " 192.168.3.102", and I installed virtulbx in my laptop.In the virtualbox I made a network of two virtual machine W2k8 and window xp of ip's 192.168.3.200 and 192.168.3.201 respectively with " internal network" option from virtulabox. Now i want to coonet the host laptop to this virtual network and also wnat that the internet is running on the laptop . Is it possible please help me in this regard

    Read the article

  • Self join in Entity Framework

    - by Waheed
    Hi, I want to have following type of query in entity frame work SELECT c2.* FROM Category c1 INNER JOIN Category c2 ON c1.CategoryID = c2.ParentCategoryID WHERE c1.ParentCategoryID is NULL How to do the above work in Entity framework...

    Read the article

  • sort mysql query by filtered query

    - by kalpaitch
    I have two mysql queries: $sql = "SELECT * FROM content WHERE threadName LIKE '%$filter%' ORDER BY lastUpdated desc"; and $sql = "SELECT * FROM content ORDER BY lastUpdated desc"; The end result is to have all rows returned from a particular table 'content' but have those that match the variable $filter at the top. Is there either a single query that could combine these two or should I be using a JOIN?

    Read the article

  • Left Join in Subsonic3

    - by muek
    Hi there, I'm new in subsonic3, and I'm getting some errors when I try to use LeftJoin var q = from c in categories join p in products on c equals p.Category into ps from p in ps.DefaultIfEmpty() select new { Category = c, ProductName = p == null ? "(No products)" : p.ProductName }; The error is "System.Collections.Generic.Enumerable '...' cannot be used for parameter of type System.Linq.IQueryable Does anyone had this error before? Did you fix it? Thanks

    Read the article

  • LINQ to SQL get grouped MIN with JOIN

    - by Ira Rainey
    I'm having trouble with a LINQ to SQL query getting the min value using Visual Basic. Here's the SQL: SELECT RC.AssetID, MIN(RC.RecCode) AS RecCode, JA.EngineerNote from JobAssetRecCode RC JOIN JobAssets JA ON JA.AssetID = RC.AssetID AND JA.JobID = RC.JobID WHERE RC.InspState = 2 AND RC.RecCode > 0 AND RC.JobID = @JobID GROUP BY RC.AssetID, JA.EngineerNote; I seem to be going around in circles here with grouping etc not managing to get it working. Any help would be greatly appreciated.

    Read the article

  • Hadoop/Pig Cross-join

    - by sagie
    Hi I am using Pig to cross join two data sets, both with format. This will result as . In my case, if I have both tuples and , it is a duplication. Can I filter those duplications (or not joining them at all)? thanks, Sagie

    Read the article

  • Django ManyToMany join query

    - by Hanpan
    I'm sure this is really simple, but I can't for the life of me find any documentation explaining how to do this. How do I get the results of a ManyToMany field inside a join as opposed to doing this: {% for tag in article.tags.all %} Which results in an extra query? What I'd like to do is fetch all related tags when I retrieve the initial article, so I could then do something like: {% for tag in article.tags %} Without the .all and the extra query. Thanks!

    Read the article

  • LINQ Joining in c# with multiple conditions

    - by Ratheesh
    Hi Following query is not working is there any problem with it? var possibleSegments = from epl in eventPotentialLegs join sd in segmentDurations on new { epl.ITARequestID, epl.ITASliceNumber, epl.DepartAirportAfter, epl.AirportId_Origin, epl.AirportId_Destination } equals new { sd.ITARequestId, sd.SliceIndex, sd.OriginAirport, sd.DestinationAirport } where epl.DepartAirportAfter > sd.UTCDepartureTime and epl.ArriveAirportBy > sd.UTCArrivalTime select new PossibleSegments{ ArrivalTime = sd.arrivalTime };

    Read the article

  • sql sum data from multiple tables

    - by Iulian
    I have 2 tables AP and INV where both have the columns [PROJECT] and [Value]. I want a query to return something like this : PROJECT | SUM_AP | SUM_INV I came up with the code below but it's returning the wrong results ( sum is wrong ). SELECT SUM(AP.Value) AS SUM_AP, SUM(INV.Value) AS SUM_INV FROM AP INNER JOIN INV ON (AP.[PROJECT] =INV.[PROJECT]) WHERE AP.[PROJECT] = 'XXXXX' GROUP BY AP.[PROJECT]

    Read the article

  • Adding a third table to a Join

    - by John
    Hello, This query works fine: $sqlStr = "SELECT s.loginid, s.title, s.url, s.displayurl, l.username FROM submission AS s, login AS l WHERE s.loginid = l.loginid ORDER BY s.datesubmitted DESC LIMIT 10"; Would this work if I wanted to join a third MySQL table (called "comment") to it? $sqlStr = "SELECT s.loginid, s.submissionid s.title, s.url, s.displayurl, l.username, count(c.comment) countComments FROM submission AS s, login AS l, comment AS c, WHERE s.loginid = l.loginid AND s.submissionid = c.submissionid ORDER BY s.datesubmitted DESC LIMIT 10"; Thanks in advance, John

    Read the article

  • sorting two tables (full join)

    - by Ruslan
    i'm joining tables like: select * from tableA a full join tableB b on a.id = b.id But the output should be: row without null fields row with null fields in tableB row with null fields in tableA Like: a.id a.name b.id b.name 5 Peter 5 Jones 2 Steven 2 Pareker 6 Paul null null 4 Ivan null null null null 1 Smith null null 3 Parker

    Read the article

  • Correlated SQL Join Query from multiple tables

    - by SooDesuNe
    I have two tables like the ones below. I need to find what exchangeRate was in effect at the dateOfPurchase. I've tried some correlated sub queries, but I'm having difficulty getting the correlated record to be used in the sub queries. I expect a solution will need to follow this basic outline: SELECT only the exchangeRates for the applicable countryCode From 1. SELECT the newest exchangeRate less than the dateOfPurchase Fill in the query table with all the fields from 2. and the purchasesTable. My Tables: purchasesTable: > dateOfPurchase | costOfPurchase | countryOfPurchase > 29-March-2010 | 20.00 | EUR > 29-March-2010 | 3000 | JPN > 30-March-2010 | 50.00 | EUR > 30-March-2010 | 3000 | JPN > 30-March-2010 | 2000 | JPN > 31-March-2010 | 100.00 | EUR > 31-March-2010 | 125.00 | EUR > 31-March-2010 | 2000 | JPN > 31-March-2010 | 2400 | JPN costOfPurchase is in whatever the local currency is for a given countryCode exchangeRateTable > effectiveDate | countryCode | exchangeRate > 29-March-2010 | JPN | 90 > 29-March-2010 | EUR | 1.75 > 30-March-2010 | JPN | 92 > 31-March-2010 | JPN | 91 The results of the query that I'm looking for: > dateOfPurchase | costOfPurchase | countryOfPurchase | exchangeRate > 29-March-2010 | 20.00 | EUR | 1.75 > 29-March-2010 | 3000 | JPN | 90 > 30-March-2010 | 50.00 | EUR | 1.75 > 30-March-2010 | 3000 | JPN | 92 > 30-March-2010 | 2000 | JPN | 92 > 31-March-2010 | 100.00 | EUR | 1.75 > 31-March-2010 | 125.00 | EUR | 1.75 > 31-March-2010 | 2000 | JPN | 91 > 31-March-2010 | 2400 | JPN | 91 So for example in the results, the exchange rate, in effect for EUR on 31-March was 1.75. I'm using Access, but a MySQL answer would be fine too. UPDATE: Modification to Allan's answer: SELECT dateOfPurchase, costOfPurchase, countryOfPurchase, exchangeRate FROM purchasesTable p LEFT OUTER JOIN (SELECT e1.exchangeRate, e1.countryCode, e1.effectiveDate, min(e2.effectiveDate) AS enddate FROM exchangeRateTable e1 LEFT OUTER JOIN exchangeRateTable e2 ON e1.effectiveDate < e2.effectiveDate AND e1.countryCode = e2.countryCode GROUP BY e1.exchangeRate, e1.countryCode, e1.effectiveDate) e ON p.dateOfPurchase >= e.effectiveDate AND (p.dateOfPurchase < e.enddate OR e.enddate is null) AND p.countryOfPurchase = e.countryCode I had to make a couple small changes.

    Read the article

  • Using Include() with inherited entities problem

    - by Peter Stegnar
    In EF eager loading related entities is easy. But I'm having difficulties including inherited entities when loading data using table-per-type model. This is my model: Entities: ArticleBase (base article entity) ArticleSpecial (inherited from ArticleBase) UserBase (base user entity) UserSpecial (inherited from UserBase) Image Relations are as shown on the image (omitting many columns): In reality my users are always of type UserSpecial, since UserBase is used in another application, thus we can share credentials. That's the only reason I have two separate tables. UserBase table can't be changed in any way shape or form, because the other app would break. Question How am I suppose to load ArticleSpecial with both CreatedBy and EditedBy set, so that both are of type UserSpecial (that defines Image relation)? I've tried (unsuccessfully though) these options: 1. Using lambda expressions: context.ArticleBases .OfType<ArticleSpecial>() .Include("UserCreated.Image") .Include("UserEdited.Image"); In this case the problem is that both CreatedBy and EditedBy are related to UserBase, that doesn't define Image navigation. So I should somehow cast these two to UserSpecial type like: context.ArticleBases .OfType<ArticleSpecial>() .Include("UserCreated<UserSpecial>.Image") .Include("UserEdited<UserSpecial>.Image"); But of course using generics in Include("UserCreated<UserSpecial>.Image") don't work. 2. I have tried using LINQ query var results = from articleSpecial in ctx.ArticleBase.OfType<ArticleSpecial>() join created in ctx.UserBase.OfType<UserSpecial>().Include("Image") on articleSpecial.UserCreated.Id equals created.Id join edited in ctx.UserBase.OfType<UserSpecial>().Include("Image") on articleSpecial.UserEdited.Id equals edited.Id select articleSpecial; In this case I'm only getting ArticleSpecial object instances without related properties being set. I know I should select those somehow, but I don't know how? Select part in my LINQ could be changed to something like select new { articleSpecial, articleSpecial.UserCreated, articleSpecial.UserEdited }; but images are still not loaded into my context. My joins in this case are barely used to filter out articleSpecial results, but they don't load entities into context (I suppose). Can anybody provide any help regarding this problem? I think it's not so uncommon.

    Read the article

  • How to optimize this mysql query - explain output included

    - by Sandeepan Nath
    This is the query (a search query basically, based on tags):- select SUM(DISTINCT(ttagrels.id_tag in (2105,2120,2151,2026,2046) )) as key_1_total_matches, td.*, u.* from Tutors_Tag_Relations AS ttagrels Join Tutor_Details AS td ON td.id_tutor = ttagrels.id_tutor JOIN Users as u on u.id_user = td.id_user where (ttagrels.id_tag in (2105,2120,2151,2026,2046)) group by td.id_tutor HAVING key_1_total_matches = 1 And following is the database dump needed to execute this query:- CREATE TABLE IF NOT EXISTS `Users` ( `id_user` int(10) unsigned NOT NULL auto_increment, `id_group` int(11) NOT NULL default '0', PRIMARY KEY (`id_user`), KEY `Users_FKIndex1` (`id_group`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=730 ; INSERT INTO `Users` (`id_user`, `id_group`) VALUES (303, 1); CREATE TABLE IF NOT EXISTS `Tutor_Details` ( `id_tutor` int(10) unsigned NOT NULL auto_increment, `id_user` int(10) NOT NULL default '0', PRIMARY KEY (`id_tutor`), KEY `Users_FKIndex1` (`id_user`), KEY `id_user` (`id_user`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=58 ; INSERT INTO `Tutor_Details` (`id_tutor`, `id_user`) VALUES (26, 303); CREATE TABLE IF NOT EXISTS `Tags` ( `id_tag` int(10) unsigned NOT NULL auto_increment, `tag` varchar(255) default NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2957 ; INSERT INTO `Tags` (`id_tag`, `tag`) VALUES (2026, 'Brendan.\nIn'), (2046, 'Brendan.'), (2105, 'Brendan'), (2120, 'Brendan''s'), (2151, 'Brendan)'); CREATE TABLE IF NOT EXISTS `Tutors_Tag_Relations` ( `id_tag` int(10) unsigned NOT NULL default '0', `id_tutor` int(10) unsigned default NULL, `tutor_field` varchar(255) default NULL, `cdate` timestamp NOT NULL default CURRENT_TIMESTAMP, `udate` timestamp NULL default NULL, KEY `Tutors_Tag_Relations` (`id_tag`), KEY `id_tutor` (`id_tutor`), KEY `id_tag` (`id_tag`), KEY `id_tutor_2` (`id_tutor`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `Tutors_Tag_Relations` (`id_tag`, `id_tutor`, `tutor_field`, `cdate`, `udate`) VALUES (2105, 26, 'firstname', '2010-06-17 17:08:45', NULL); ALTER TABLE `Tutors_Tag_Relations` ADD CONSTRAINT `Tutors_Tag_Relations_ibfk_2` FOREIGN KEY (`id_tutor`) REFERENCES `Tutor_Details` (`id_tutor`) ON DELETE NO ACTION ON UPDATE NO ACTION, ADD CONSTRAINT `Tutors_Tag_Relations_ibfk_1` FOREIGN KEY (`id_tag`) REFERENCES `Tags` (`id_tag`) ON DELETE NO ACTION ON UPDATE NO ACTION; What the query does? This query actually searches tutors which contain "Brendan"(as their name or biography or something). The id_tags 2105,2120,2151,2026,2046 are nothing but the tags which are LIKE "%Brendan%". My question is :- 1.In the explain of this query, the reference column shows NULL for ttagrels, but there are possible keys (Tutors_Tag_Relations,id_tutor,id_tag,id_tutor_2). So, why is no key being taken. How to make the query take references. Is it possible at all? 2. The other two tables td and u are using references. Any indexing needed in those? I think not. Check the explain query output here http://www.test.examvillage.com/explain.png

    Read the article

< Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >