Search Results

Search found 33242 results on 1330 pages for 'database optimization'.

Page 385/1330 | < Previous Page | 381 382 383 384 385 386 387 388 389 390 391 392  | Next Page >

  • explain these select statements!

    - by user329820
    Hi, I can not get the difference betwwn these statements? would you please help me,I have read some sample of select statements but I did not get these ones. SELECT 'B' FROM T WHERE A = (SELECT NULL); SELECT 'C' FROM T WHERE A = ANY (SELECT NULL); SELECT 'D' FROM T WHERE A = A; I use MySQL

    Read the article

  • I have data about deadlocks, but I can't understand why they occur

    - by Alex
    I am receiving a lot of deadlocks in my big web application. http://stackoverflow.com/questions/2941233/how-to-automatically-re-run-deadlocked-transaction-asp-net-mvc-sql-server Here I wanted to re-run deadlocked transactions, but I was told to get rid of the deadlocks - it's much better, than trying to catch the deadlocks. So I spent the whole day with SQL Profiler, setting the tracing keys etc. And this is what I got. There's a Users table. I have a very high usable page with the following query (it's not the only query, but it's the one that causes troubles) UPDATE Users SET views = views + 1 WHERE ID IN (SELECT AuthorID FROM Articles WHERE ArticleID = @ArticleID) And then there's the following query in ALL pages: User = DB.Users.SingleOrDefault(u => u.Password == password && u.Name == username); That's where I get User from cookies. Very often a deadlock occurs and this second Linq-to-SQL query is chosen as a victim, so it's not run, and users of my site see an error screen. I read a lot about deadlocks... And I don't understand why this is causing a deadlock. So obviously both of this queries run very often. At least once a second. Maybe even more often (300-400 users online). So they can be run at the same time very easily, but why does it cause a deadlock? Please help. Thank you

    Read the article

  • how to get transform a local image to a web accessable image

    - by hguser
    Hi: Generally,if we want to display a image in the web page,we give the uri of the image resource like: http://host:port/image/xxx.jpg. Now,there are some images in my file system,and I save its absolute path in the db. Like this; id name address image 1 xxxx xxxx C:/images/xxx.jpg Now if the entity is retrived,its image should be displayed in the page. How to make it? What I thought is copy the image under the web server dir,then build its url,then the page can render it. But I wonder if this is a good idea? Is there any other way?

    Read the article

  • Dmbedded couchDB

    - by Chang
    CouchDB is great, I like its replication functionality, but it's a bit larger and slower when used in desktop application. As I tested in intel duo core cpu, 12 seconds to load 10000 docs 10 seconds to insert 10000 doc, but need 20 seconds to update view, so total is 30 seconds Is there any No SQL implementation which has the same replication functionality, but the size is very small, and the speed is quite good( 1 second to load 10000 docs). Thanks

    Read the article

  • What is the fastest findByName query with hibernate?

    - by Karussell
    I am sure I can improve the performance of the following findByName query of hibernate: public List<User> findByName(String name) { session.createCriteria(User.class).add(Restrictions.eq("name", name)).list(); } In which way should I improve it or even more important: in which ways should I improve it first? I will need the full object with all the collections (layz or not) and deps of this class.

    Read the article

  • Synchronizing MySQL databases

    - by Wasim
    Hi all, I have a maintanance problem synchronizing my MySQL data bases . These are the databases I have : My development DB : Here I make my curret development changes . Staging DB : I need to make all the changes I did in the development on it before using , currently I hold migration scripts for structure and data. Production DB : A production environment . Have to do exacly the same as the staging . My problem , is sync. the structure , and some of the data. This is really a very hard work to maintaine. Is there any technics , tools to do with MySQL . What is replication , is it good for my situation , how to use it . Thanks in advance ...

    Read the article

  • Transaction within transaction

    - by user281521
    Hello, I want to know if open a transaction inside another is safe and encouraged? I have a method: def foo(): session.begin try: stuffs except Exception, e: session.rollback() raise e session.commit() and a method that calls the first one, inside a transaction: def bar(): stuffs try: foo() #<<<< there it is :) stuffs except Exception, e: session.rollback() raise e session.commit() if I get and exception on the foo method, all the operations will be rolled back? and everything else will work just fine? thanks!!

    Read the article

  • Better alternative to autonumber primary keys

    - by Comrad_Durandal
    I am looking for a better primary key than the autonumber data type, namely for the reason that it's limited to a long integer, when I really just need the field to reflect a number or text string that will never ever repeat, no matter HOW many records are added or deleted from the table. The problem is I am not sure how to implement something like turning the current date and time into a hexadecimal string and using that as a unique field I can use as a primary key. Am I just being too paranoid about running out of space?

    Read the article

  • Trying to create fields based on a case statement

    - by dido
    I'm having some trouble with the query below. I am trying to determine if the "category" field is A, B or C and then creating a field based on the category. That field would sum up payments field. But I'm running into error saying "incorrect syntax near keyword As". I am creating this in a SQL View. Using SQL Server 2008 SELECT r.id, r.category CASE WHEN r.category = 'A' then SUM(r.payment) As A_payments WHEN r.category = 'B' then SUM(r.payment) As B_payments WHEN r.category = 'C' then SUM(r.payment) As C_payments END FROM r_invoiceTable As r GROUP BY r.id, r.category I have data where all of the above cases should be executed because the data that I have has A,B and C Sample Data- r_invoiceTable Id --- Category ---- Payment 222 A ---- 50 444 A ---- 30 111 B ---- 90 777 C ---- 20 555 C ---- 40 Desired Output A_payments = 80, B_payments = 90, C_payments = 60

    Read the article

  • How should I migrate DDL changes from one environment to the next?

    - by Rl
    I make DDL changes using SQL Developer's GUI. Problem is, I need to apply those same changes to the test environment. I'm wondering how others handle this issue. Currently I'm having to manually write ALTER statements to bring the test environment into alignment with the development environment, but this is prone to error (doing the same thing twice). In cases where there's no important data in the test environment I usually just blow everything away, export the DDL scripts from dev and run them from scratch in test. I know there are triggers that can store each DDL change, but this is a heavily shared environment and I would like to avoid that if possible. Maybe I should just write the DDL stuff manually rather than using the GUI?

    Read the article

  • How do i get the data from a surveillance camera to a storage i can stream from?

    - by radbyx
    Hi my sisters house was robbed chrismas evening :( I talked with her about making a surveillance system for her. The idea is to have a system that detects intruders and then send a SMS to you while streaming it to a private website. The hard part: How and where do I storage the data from the camera so it's streamable? I think i can manage to do the streaming, website and SMS server, but i need the data (fundamentation). Thanks, any help is much appriciated.

    Read the article

  • Zend Framework Relations vs. Table Select

    - by rtmilker
    Hey! I just want to know your guys opinion on using join tables within the zend framework. Of course you can use relations by defining a referenceMap and dependentTables and stuff, or using setIntegrityCheck(false) within a db select(). The setIntegrityCheck version seems a little bit dirty to me, but the other version is not very suitable for big querys and joining many tables... I'm a PHP developer for 5 years now and new to the zend framework and just want get a direction for my first project. Thanks!!!

    Read the article

  • about Select statement !

    - by user329820
    hi, I have read that after select we use column-names but I have found a statement that was like this: SELECT 'A' FROM T WHERE A = NULL; would you lease help me? thanks (A is a column- name here?) my DBMS is MySQL

    Read the article

  • How to find the entity with the greatest primary key?

    - by simpatico
    I've an entity LearningUnit that has an int primary key. Actually, it has nothing more. Entity Concept has the following relationship with it: @ManyToOne @Size(min=1,max=7) private LearningUnit learningUnit; In a constructor of Concept I need to retrieve the LearningUnit with the greatest primary key. If no LearningUnit exists yet I instantiate one. I then set this.learningUnit to the retrieved/instantied. Finally, I call the empty constructor of Concept in a try-catch block, to have the entitymanager do the cardinality check. If an exception is thrown (I expect one in the case that already another 7 Concepts are referring to the same LearningUnit. In that case, I case instantiate a new LearningUnit with a new greater primary key. Please, also point out, if any, clear pitfalls in my outlined algorithm above.

    Read the article

  • Question about Benchmark funcion in Mysql ( Incredible results ).

    - by xRobot
    I have 2 tables: author with 3 millions of rows. book with 20 miles rows. . So I have benchmarked this query with a join: SELECT BENCHMARK(100000000, 'SELECT book.title, author.name FROM `book` , `author` WHERE book.id = author.book_id ') And this is the result: Query took 0.7438 sec ONLY 0.7438 seconds for 100 millions of query with a join ??? Do I make some mistakes or this is the right result ?

    Read the article

  • making query from different related tables using codeigniter

    - by fatemeh karam
    I'm using codeigniter as i mentioned this is a part of my view code foreach($projects_query as $row)// $row indicates the projects { ?> <tr><td><h3><button type="submit" class="button red-gradient glossy" name = "project_click" > <?php echo $row->txtTaskName; ?></button></h3></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr> <?php foreach($tasks_query as $row2) { // if( $row->txtTaskName == "TestProject") if($row->intTaskID == $row2->intInside)// intInside indicades that the current task($row2) is the subset of which task (system , subsystem or project) { if($row2->intSummary == 0)//if the task(the system) is an executable task & doesn't have any subtask: { $query_team_user_id = $this->admin_in_out_model->get_user_team_task_query($row2->intTaskID);//runs the function and generates a query from tbl_userteamtask where intTaskID equals to the selected row's intTaskID foreach($query_team_user_id as $row_teamid) { $query_teamname = $this->admin_in_out_model->get_team_name($row_teamid->intTeamID); $query_fn_ln = $this->admin_in_out_model->get_fn_ln_from_userid($row_teamid->intUserID); foreach($query_teamname as $row_teamname) {?> <tr><td></td><td></td><td><h4> <?php echo $row2->txtTaskName;?></h4></td> <td><b><font color='#F33558'><?php echo $row_teamname->txtTeamName;?></font></b></td> <?php } foreach($query_fn_ln as $row_f_l_name) {?> <td> <?php echo $row_f_l_name->txtFirstname." ".$row_f_l_name->txtLastname;?></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td> <?php }?> </tr> <?php } } else{ ?> <tr><td></td><td></td><td><h4> <?php echo $row2->txtTaskName;?></h4></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><?php } foreach($tasks_query as $row_subsystems) { if($row_subsystems->intInside == $row2->intTaskID )//if the task is the subtask of a system(it means the task is a subsystem) { if($row_subsystems->intSummary == 0)//if the task is an executable task & doesn't have any subtask: { $query_team_user_id = $this->admin_in_out_model->get_user_team_task_query($row_subsystems->intTaskID); foreach($query_team_user_id as $row_teamid) {?> <tr><?php $query_teamname = $this->admin_in_out_model->get_team_name($row_teamid->intTeamID); $query_fn_ln = $this->admin_in_out_model->get_fn_ln_from_userid($row_teamid->intUserID); foreach($query_teamname as $row_teamname) {?> <td></td><td></td><td><h5><?php echo $row_subsystems->txtTaskName?></h5><br/></td> <td><b><font color='#F33558'><?php echo $row_teamname->txtTeamName;?></font></b></td><?php } foreach($query_fn_ln as $row_f_l_name) {?> <td><?php echo $row_f_l_name->txtFirstname." ".$row_f_l_name->txtLastname;?></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><?php }?> </tr><?php } } else{ ?><tr><td></td><td></td><td><h5><?php echo $row_subsystems->txtTaskName?></h5></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><?php } foreach($tasks_query as $row_tasks) { if($row_tasks->intInside == $row_subsystems->intTaskID )//if the task is the subtask of a subsystem { if($row_tasks->intSummary == 0)//if the task is an executable task & doesn't have any subtask: { $query_team_user_id = $this->admin_in_out_model->get_user_team_task_query($row_tasks->intTaskID); foreach($query_team_user_id as $row_teamid) {?> <tr><?php $query_teamname = $this->admin_in_out_model->get_team_name($row_teamid->intTeamID); $query_fn_ln = $this->admin_in_out_model->get_fn_ln_from_userid($row_teamid->intUserID); foreach($query_teamname as $row_teamname) {?> <td></td><td></td><td><b><?php echo $row_tasks->txtTaskName;?></b></td> <td><b><font color='#F33558'><?php echo $row_teamname->txtTeamName;?></font></b></td><?php } foreach($query_fn_ln as $row_f_l_name) {?> <td><?php echo $row_f_l_name->txtFirstname." ".$row_f_l_name->txtLastname;?></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><?php }?> </tr><?php } } } } } } } } }?> and in controller i have $projects_query = $this->admin_in_out_model->get_projects(); $tasks_query = $this->admin_in_out_model->get_systems(); $userteamtask = $this->admin_in_out_model->get_user_team_task(); $data['tasks_query'] = $tasks_query; $data['projects_query'] = $projects_query; $this->load->view('project_view',$data); but as you see I'm calling my model functions within the view how can i do something else to do this i mean not calling my model function in my view I have to add that, my model function have parameters these are the model functions: function get_projects() { $this -> db -> select('*'); $this -> db -> from('tbl_task'); $this -> db -> where('intInside','0'); $query = $this->db->get(); return $query->result(); } function get_systems() { $this -> db -> select('*'); $this -> db -> from('tbl_task '); $this -> db -> where('intInside <> ','0'); $query = $this->db->get(); return $query->result(); } function get_user_team_task_query($task_id)//gets information from tbl_userteamtask where the field intTaskID is equal to $task_id { $this -> db -> select('*'); $this -> db -> from('tbl_userteamtask'); $this -> db -> where('intTaskID',$task_id); $query_teamid = $this->db->get(); return $query_teamid->result(); } function get_user_team_task()//gets information from tbl_userteamtask where the field intTaskID is equal to $task_id { $this -> db -> select('*'); $this -> db -> from('tbl_userteamtask'); // $this -> db -> where('intTaskID',$task_id); $query_teamid = $this->db->get(); return $query_teamid->result(); } function get_team_name($query_teamid) { $this -> db -> select('*'); $this -> db -> from('tbl_team'); $this -> db -> where('intTeamID',$query_teamid); $query_teamname = $this->db->get(); return $query_teamname->result(); } function get_user_name($query_userid) { $this -> db -> select('*'); $this -> db -> from('tbl_user'); $this -> db -> where('intUserID',$query_userid); $query_username = $this->db->get(); return $query_username->result(); } function get_fn_ln_from_userid($selected_id) { $this -> db -> select('tbl_user.intUserID, tbl_user.intPersonID,tbl_person.intPersonID,tbl_person.txtFirstname, tbl_person.txtLastname'); $this -> db -> from('tbl_user , tbl_person'); $where = "tbl_user.intPersonID = tbl_person.intPersonID "; $this -> db -> where($where); $this -> db -> where('tbl_user.intUserID', $selected_id); $query = $this -> db -> get();//makes query from DB return $query->result(); } do I have to use subquery ? is this true? i mean can i do this? foreach( $data as $key => $each ) { $data[$key]['team_id'] = $this->get_user_team_task_query( $each['intTaskID'] ); foreach($data[$key]['team_id'] as $key_teamname => $each) { $data[$key_teamname]['team_name'] = $this->get_team_name( $each['intTeamID'] ); } } the model code: foreach( $data as $key => $each ) { $data[$key]['intTaskID'] = $each['intTaskID']; $data[$key]['team_id'] = $this->get_user_team_task_query( $each['intTaskID'] ); foreach($data[$key]['team_id'] as $key => $each) { $data[$key]['team_name'] = $this->get_team_name( $each['intTeamID'] ); #fetching of the teamname and saving in the array $data[$key]['user_name'] = $this->get_fn_ln_from_userid( $each['intUserID'] ); foreach($data[$key]['user_name'] as $key => $each) { $data[$key]['first_name'] = $each['txtFirstname'] ; $data[$key]['last_name'] = $each['txtLastname'] ; } $data[$key]['first_name'] = $data[$key]['first_name']; $data[$key]['last_name'] = $data[$key]['last_name']; } }

    Read the article

  • What type of data store should I use for my ios app?

    - by mwiederrecht
    I am pretty new to ios and using servers so forgive me. I am building an ios app for research. I need to monitor things that the user does and then push it up to a server for analysis (yes, with user and IRB permission). On the client's side I need to keep quite a bit of data that won't really change except in the case of pulling an updated version from the server, and then a minimal amount of user-specific data. Most of the data I will collect needs to be pushed to a server for analysis and then can be deleted from the client side. I am struggling to figure out what kind of data store I need to use, especially since I am not quite sure how the pushing and pulling from the server process works yet. Does it make sense to use Core Data? XML? SQLite? I like the Core Data idea, but I am not sure what kind of problems I will run into when I need to send large amounts of data to it and from it from the server. I imagine I might need to send data in a different form than it is probably stored in on either end - so what kind of overhead am I likely to run into in the process of converting that data? Is there a good format to save stuff in that would work well for me on both ends AND for sending the data? As you can probably tell, I could use some advice. Thanks!

    Read the article

< Previous Page | 381 382 383 384 385 386 387 388 389 390 391 392  | Next Page >