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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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  • SSL over TDS, SQL Server 2005 Express

    - by reuvenab
    I capture packets sent/received by Win Xp machine when connecting to SQL Server 2005 Express using TLS encryption. Server and Client exchange Hello messages Server and Client send ChangeCipherSpec message Then Server and Client server send strange message that is not described in TLS protocol What is the message and if SSL over TDS is standard compliant at all? Server side capture: 16 **SSL Handshake** 03 01 00 4a 02 ServerHello 00 00 46 03 01 4b dd 68 59 GMT 33 13 37 98 10 5d 57 9d ff 71 70 dc d6 6f 9e 2c Random[00..13] cb 96 c0 2e b3 2f 9b 74 67 05 cc 96 Random[14..27] 20 72 26 00 00 0f db 7f d9 b0 51 c2 4f cd 81 4c Session ID 3f e3 d2 d1 da 55 c0 fe 9b 56 b7 6f 70 86 fe bb Session ID 54 Session ID 00 04 Cipher Suite 00 Compression 14 03 01 00 01 01 **ChangeCipherSpec** 16 03 01 ???? Finished ??? 00 20 d0 da cc c4 36 11 43 ff 22 25 8a e1 38 2b ???? ??? 71 ce f3 59 9e 35 b0 be b2 4b 1d c5 21 21 ce 41 ???? ??? 8e 24

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  • Getting wierd issue with TO_NUMBER function in Oracle

    - by Fazal
    I have been getting an intermittent issue when executing to_number function in the where clause on a varchar2 column if number of records exceed a certain number n. I used n as there is no exact number of records on which it happens. On one DB it happens after n was 1 million on another when it was 0.1. million. E.g. I have a table with 10 million records say Table Country which has field1 varchar2 containing numberic data and Id If I do a query as an example select * from country where to_number(field1) = 23 and id 1 and id < 100000 This works But if i do the query select * from country where to_number(field1) = 23 and id 1 and id < 100001 It fails saying invalid number Next I try the query select * from country where to_number(field1) = 23 and id 2 and id < 100001 It works again As I only got invalid number it was confusing, but in the log file it said Memory Notification: Library Cache Object loaded into SGA Heap size 3823K exceeds notification threshold (2048K) KGL object name :with sqlplan as ( select c006 object_owner, c007 object_type,c008 object_name from htmldb_collections where COLLECTION_NAME='HTMLDB_QUERY_PLAN' and c007 in ('TABLE','INDEX','MATERIALIZED VIEW','INDEX (UNIQUE)')), ws_schemas as( select schema from wwv_flow_company_schemas where security_group_id = :flow_security_group_id), t as( select s.object_owner table_owner,s.object_name table_name, d.OBJECT_ID from sqlplan s,sys.dba_objects d It seems its related to SGA size, but google did not give me much help on this. Does anyone have any idea about this issue with TO_NUMBER or oracle functions for large data?

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  • What database systems should an startup company consider?

    - by Am
    Right now I'm developing the prototype of a web application that aggregates large number of text entries from a large number of users. This data must be frequently displayed back and often updated. At the moment I store the content inside a MySQL database and use NHibernate ORM layer to interact with the DB. I've got a table defined for users, roles, submissions, tags, notifications and etc. I like this solution because it works well and my code looks nice and sane, but I'm also worried about how MySQL will perform once the size of our database reaches a significant number. I feel that it may struggle performing join operations fast enough. This has made me think about non-relational database system such as MongoDB, CouchDB, Cassandra or Hadoop. Unfortunately I have no experience with either. I've read some good reviews on MongoDB and it looks interesting. I'm happy to spend the time and learn if one turns out to be the way to go. I'd much appreciate any one offering points or issues to consider when going with none relational dbms?

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  • Telerik RadGrid: grid clientside pagination

    - by ram
    I have a web service which returns me some data,I am massaging this data and using this as datasource for my radgrid (telerik). The datasource is quite large, and would like to paginate it. I found couple of problems when I paginate it in the server side I have to bind the grid again for pagination, which essentially means I have to make a call to WS again to get the data. This is an expensive call for me. I would rather forgo the benefits of pagination and would display all the results in the same page, except for it would be a bit clumsy During the postback RadGrid1.Items.Count happens to be the number of items getting paginated (25- in my case) which is expected as all the items in the datasource are not getting bound. This of course is not an issue. The real issue is that we have some checkboxes which get checked based on some business condition. We add this to our business object/DB later. So if the user has not navigated all the pages, these "checked" items do not get added as pagination limits the "Items" in the grid to those which get bound for that particular page index. My Thoughts: I would rather have some sort of client side pagination, where we can hide/show contents than going to the server and doing a databind every time. Though it will return all the results, the UI will not be clumsy and the grid would have "all the items" during postback Is there a way to do it ? If it were a regular asp.net gridView, can someone point me to a good article which would serve my purpose Ram PS: who else think radgrid is crazy ? (unfortunately I did not make this choice)

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  • PHP/MySQL allowing current user to edit there account information

    - by user1837896
    i have created 2 pages update.php edit.php we start on edit.php so here is edit.php's script <?php session_start(); $id = $_SESSION["id"]; $username = $_POST["username"]; $fname = $_POST["fname"]; $password = $_POST["password"]; $email = $_POST["email"]; mysql_connect('mysql13.000webhost.com', 'a2670376_Users', 'Password') or die(mysql_error()); echo "MySQL Connection Established! <br>"; mysql_select_db("a2670376_Pass") or die(mysql_error()); echo "Database Found! <br>"; $query = "UPDATE members SET username = '$username', fname = '$fname', password = '$password' WHERE id = '$id'"; $res = mysql_query($query); if ($res) echo "<p>Record Updated<p>"; else echo "Problem updating record. MySQL Error: " . mysql_error(); ?> <form action="update.php" method="post"> <input type="hidden" name="id" value="<?=$id;?>"> ScreenName:<br> <input type='text' name='username' id='username' maxlength='25' style='width:247px' name="username" value="<?=$username;?>"/><br> FullName:<br> <input type='text' name='fname' id='fname' maxlength='20' style='width:248px' name="ud_img" value="<?=$fname;?>"/><br> Email:<br> <input type='text' name='email' id='email' maxlength='50' style='width:250px' name="ud_img" value="<?=$email;?>"/><br> Password:<br> <input type='text' name='password' id='password' maxlength='25' style='width:251px' value="<?=$password;?>"/><br> <input type="Submit"> </form> now here is the update.php page where i am having the MAJOR problem <?php session_start(); mysql_connect('mysql13.000webhost.com', 'a2670376_Users', 'Password') or die(mysql_error()); mysql_select_db("a2670376_Pass") or die(mysql_error()); $id = (int)$_SESSION["id"]; $username = mysql_real_escape_string($_POST["username"]); $fname = mysql_real_escape_string($_POST["fname"]); $email = mysql_real_escape_string($_POST["email"]); $password = mysql_real_escape_string($_POST["password"]); $query="UPDATE members SET username = '$username', fname = '$fname', email = '$email', password = '$password' WHERE id='$id'"; mysql_query($query)or die(mysql_error()); if(mysql_affected_rows()>=1){ echo "<p>($id) Record Updated<p>"; }else{ echo "<p>($id) Not Updated<p>"; } ?> now on edit.php i fill out the form to edit the account "test" while i am logged into it now once the form if filled out i click on |Submit!| button and it takes me to update.php and it returns this (0) Not Updated (0) <= id of user logged in Not Updated <= MySql Error from mysql_query($query)or die(mysql_error()); if(mysql_affected_rows()>=1){ i want it to update the user logged in and if i am not mistaken in this script it says $id = (int)$_SESSION["id"]; witch updates the user with the id of the person who is logged in but it isnt updating its saying that no tables were effected if it helps heres my MySql Database picture just click here http://i50.tinypic.com/21juqfq.png if this could possibly be any help to find the solution i have 2 more files delete.php and delete_ac.php they have can remove users from my sql database and they show the user id and it works there are no bugs in this script at all PLEASE DO NOT MAKE SUGGESTIONS FOR THE SCRIPTS BELOW delete.php first <?php $host="mysql13.000webhost.com"; // Host name $username="a2670376_Users"; // Mysql username $password="PASSWORD"; // Mysql password $db_name="a2670376_Pass"; // Database name $tbl_name="members"; // Table name // Connect to server and select database. mysql_connect("$host", "$username", "$password")or die("cannot connect"); mysql_select_db("$db_name")or die("cannot select DB"); // select record from mysql $sql="SELECT * FROM $tbl_name"; $result=mysql_query($sql); ?> <table border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC"> <tr> <td colspan="8" style="bgcolor: #FFFFFF"><strong><img src="http://i47.tinypic.com/u6ihk.png" height="30" widht="30">Delete data in mysql</strong> </td> </tr> <tr> <td align="center" bgcolor="#FFFFFF"><strong>Id</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>UserName</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>FullName</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>Password</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>Email</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>Date</strong></td> <td align="center" bgcolor="#FFFFFF"><strong>Ip</strong></td> <td align="center" bgcolor="#FFFFFF">&nbsp;</td> </tr> <?php while($rows=mysql_fetch_array($result)){ ?> <tr> <td bgcolor="#FFFFFF"><? echo $rows['id']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['username']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['fname']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['password']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['email']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['date']; ?></td> <td bgcolor="#FFFFFF"><? echo $rows['ip']; ?></td> <td bgcolor="#FFFFFF"><a href="delete_ac.php?id=<? echo $rows['id']; ?>">delete</a></td> </tr> <?php // close while loop } ?> </table> <?php // close connection; sql_close(); ?> and now delete_ac.php <table width="500" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC"> <tr> <td colspan="8" bgcolor="#FFFFFF"><strong><img src="http://t2.gstatic.com/images? q=tbn:ANd9GcS_kwpNSSt3UuBHxq5zhkJQAlPnaXyePaw07R652f4StmvIQAAf6g" height="30" widht="30">Removal Of Account</strong> </td> </tr> <tr> <td align="center" bgcolor="#FFFFFF"> <?php $host="mysql13.000webhost.com"; // Host name $username="a2670376_Users"; // Mysql username $password="javascript00"; // Mysql password $db_name="a2670376_Pass"; // Database name $tbl_name="members"; // Table name // Connect to server and select databse. mysql_connect("$host", "$username", "$password")or die("cannot connect"); mysql_select_db("$db_name")or die("cannot select DB"); // get value of id that sent from address bar $id=$_GET['id']; // Delete data in mysql from row that has this id $sql="DELETE FROM $tbl_name WHERE id='$id'"; $result=mysql_query($sql); // if successfully deleted if($result){ echo "Deleted Successfully"; echo "<BR>"; echo "<a href='delete.php'>Back to main page</a>"; } else { echo "ERROR"; } ?> <?php // close connection mysql_close(); ?> </td> </tr> </table>

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  • Advice needed: cold backup for SQL Server 2008 Express?

    - by Mikey Cee
    What are my options for achieving a cold backup server for SQL Server Express instance running a single database? I have an SQL Server 2008 Express instance in production that currently represents a single point of failure for my application. I have a second physical box sitting at the installation that is currently doing nothing. I want to somehow replicate my database in near real time (a little bit of data loss is acceptable) to the second box. The database is very small and resources are utilized very lightly. In the case that the production server dies, I would manually reconfigure my application to point to the backup server instead. Although Express doesn't support log shipping, I am thinking that I could manually script a poor man's version of it, where I use batch files to take the logs and copy them across the network and apply them to the second server at 5 minute intervals. Does anyone have any advice on whether this is technically achievable, or if there is a better way to do what I am trying to do? Note that I want to avoid having to pay for the full version of SQL Server and configure mirroring as I think it is an overkill for this application. I understand that other DB platforms may present suitable options (eg. a MySQL Cluster), but for the purposes of this discussion, let's assume we have to stick to SQL Server.

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  • How to use Nhibernate Validator + NHib component + ddl

    - by mynkow
    I just configured my NHibValidator. My NHibernate creates the DB schema. When I set MaxLenght="20" to some property of a class then in the database the length appears in the database column. I am doing this in the NHibValidator xml file. But the problem is that I have components and cannot figure out how to achieve this behaviour. The component is configured correctly in the Customer.hbm.xml file. EDIT: Well, I found that Hibernate Validator users had the same problem two years ago. http://opensource.atlassian.com/projects/hibernate/browse/HV-25 Is this an issue for NHibernate Validator or it is fixed. If it is working tell me how please. ----------------------------------------------------- public class Customer { public virtual string Name{get;set;} public virtual Contact Contacts{ get; } } ----------------------------------------------------- public class Contact { public virtual string Address{get;set;} } ----------------------------------------------------- <?xml version="1.0" encoding="utf-8" ?> <nhv-mapping xmlns="urn:nhibernate-validator-1.0" namespace="MyNamespace" assembly="MyAssembly"> <class name="Customer"> <property name="Name"> <length max="20"/> </property> <property name="Contacts"> <notNull/> <valid/> </property> </class> </nhv-mapping> ----------------------------------------------------- <?xml version="1.0" encoding="utf-8" ?> <nhv-mapping xmlns="urn:nhibernate-validator-1.0" namespace="MyNamespace" assembly="MyAssembly"> <class name="Contact"> <property name="Address"> <length max="50"/> <valid/> </property> </class> </nhv-mapping> -----------------------------------------------------

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  • pagination and url encoding help

    - by Sufyan
    <?php $name=$_POST['name']; ?> <form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <input type="text" name="name"> <input type="submit" value="GO" name="submit"> </form> <?php include ('db.php'); if(isset($_POST['submit'])) { mysql_query ("INSERT INTO example (name) VALUES('$name')") or die(mysql_error()); } if (!isset($_GET['startrow']) or !is_numeric($_GET['startrow'])) { $startrow = 0; } else { $startrow = (int)$_GET['startrow']; } $query = "SELECT * FROM example ORDER BY id DESC LIMIT $startrow, 20"; $result = mysql_query($query) or die(mysql_error()); while($row = mysql_fetch_array($result)){ echo "<li>"; echo $row['name'] ." "." <a href= 'like.php?quote=" . urlencode( $row['name'] ) . "'>Click Here</a>"; echo "</li>"; } echo '<a href="'.$_SERVER['PHP_SELF'].'?startrow='.($startrow+10).'">Next</a>'; ?> I want to make my page links hidden , how can i make then hidden so that a user cant edit it. 2nd question, currently i am showing total 10 records on each page and then a next page button , but the next button is keep showing even when there is no more records...! how to remove a next page button when records ended. ?? line number 28 is the link to pages which can be easyily editable by any user, i wnat to make them secure (using ID) and line 35 is n'next' page link , this link should not be appear when number of records ended

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  • Html.ListBox() and MultiselectList

    - by Ivan90
    Hi guys, I've a little problem with an Html.ListBox! I am developing a personal blog in ASP.NET MVC 1.0 and I created an adminpanel where I can add and edit a post! During this two operations, I can add also tags! I think of use an Html.ListBox() helper to list all tags, and so I can select multiple tags to add in a post! The problem isn't during the add mode, but in the edit mode, where I have to pre-select post's tags! I read that I have to use a MultiSelectList and so in its constructor pass, tags' list and tag's list(pre-selected value). But I don't know how to use this class! I post, some code: This is my models method that get all list tags in selectlist public IEnumerable<SelectListItem> GetTagsListBox() { return from t in db.Tags orderby t.IDTag descending select new SelectListItem { Text = t.TagName, Value = t.IDTag.ToString(), }; } So in Edit (Get and Post), Add(Get and Post) I use a ViewData to pass this list in Html.ListBox(). ViewData["Tags"] = tagdb.GetTagsListBox(); And in my view <%=Html.ListBox("Tags",ViewData["Tags"] as SelectList) %> So with this code it's ok in Add Mode! But in Edit Mode I need to pre-select those values! So Now, of course I have to create a method that get all tagsbypostid! and then in ViewData what Must I to pass? Any suggest?

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  • MySQL bindings for Rails 2.3.5 on Mac OS X 10.5.8

    - by lach
    I have a rails environment which I set-up with macports. I recently updated macports which seems to have had the side effect of breaking rails. When I try to boot a rails server I get: $ ./script/server => Booting WEBrick => Rails 2.3.5 application starting on http://0.0.0.0:3000 /opt/local/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/gem_dependency.rb:119:Warning: Gem::Dependency#version_requirements is deprecated and will be removed on or after August 2010. Use #requirement !!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql. /opt/local/lib/ruby/vendor_ruby/1.8/i686-darwin9/mysql.bundle: dlopen(/opt/local/lib/ruby/vendor_ruby/1.8/i686-darwin9/mysql.bundle, 9): Library not loaded: /opt/local/lib/mysql5/mysql/libmysqlclient.15.dylib (LoadError) Referenced from: /opt/local/lib/ruby/vendor_ruby/1.8/i686-darwin9/mysql.bundle Reason: image not found - /opt/local/lib/ruby/vendor_ruby/1.8/i686-darwin9/mysql.bundle I've tried reinstalling the mysql gem many times using various configurations I've found around the web but nothing seems to help. Also, when I try to use rake I get: rake db:migrate Rails requires RubyGems >= 1.3.1 (you have 1.0.1). Pleasegem update --systemand try again. Even though: gem --version 1.3.6 What's going on here?

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  • SQL Server Long Query

    - by thormj
    Ok... I don't understand why this query is taking so long (MSSQL Server 2005): [Typical output 3K rows, 5.5 minute execution time] SELECT dbo.Point.PointDriverID, dbo.Point.AssetID, dbo.Point.PointID, dbo.Point.PointTypeID, dbo.Point.PointName, dbo.Point.ForeignID, dbo.Pointtype.TrendInterval, coalesce(dbo.Point.trendpts,5) AS TrendPts, LastTimeStamp = PointDTTM, LastValue=PointValue, Timezone FROM dbo.Point LEFT JOIN dbo.PointType ON dbo.PointType.PointTypeID = dbo.Point.PointTypeID LEFT JOIN dbo.PointData ON dbo.Point.PointID = dbo.PointData.PointID AND PointDTTM = (SELECT Max(PointDTTM) FROM dbo.PointData WHERE PointData.PointID = Point.PointID) LEFT JOIN dbo.SiteAsset ON dbo.SiteAsset.AssetID = dbo.Point.AssetID LEFT JOIN dbo.Site ON dbo.Site.SiteID = dbo.SiteAsset.SiteID WHERE onlinetrended =1 and WantTrend=1 PointData is the biggun, but I thought its definition should allow me to pick up what I want easily enough: CREATE TABLE [dbo].[PointData]( [PointID] [int] NOT NULL, [PointDTTM] [datetime] NOT NULL, [PointValue] [real] NULL, [DataQuality] [tinyint] NULL, CONSTRAINT [PK_PointData_1] PRIMARY KEY CLUSTERED ( [PointID] ASC, [PointDTTM] ASC ) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX [IX_PointDataDesc] ON [dbo].[PointData] ( [PointID] ASC, [PointDTTM] DESC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO PointData is 550M rows, and Point (source of PointID) is only 28K rows. I tried making an Indexed View, but I can't figure out how to get the Last Timestamp/Value out of it in a compatible way (no Max, no subquery, no CTE). This runs twice an hour, and after it runs I put more data into those 3K PointID's that I selected. I thought about creating LastTime/LastValue tables directly into Point, but that seems like the wrong approach. Am I missing something, or should I rebuild something? (I'm also the DBA, but I know very little about A'ing a DB!)

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  • Visual C++ overrides/mock objects for unit testing?

    - by Mark
    When I'm running unit tests, I want to be able to "stub out" or create a mock object, but I'm running into DLL Hell. For example: There are two DLL libraries built: A.dll and B.dll -- Classes in A.dll have calls to classes in B.dll so when A.dll was built, the link line was using B.lib for the defintions. My test driver (Foo.exe) is testing classes in A.dll, so it links against A.lib. However, I want to "stub out" some of the calls A.dll makes to B.dll with simple versions (return basic value, no DB look up, etc). I can't build an Override.dll that just overrides the needed methods (not entire classes) and replace B.dll because Foo.exe will A) complain that B.dll is missing if I just remove it and put Override.dll in it's place or B) if I rename Override.dll to B.dll, Foo.exe complains that there are unresolved symbols because Override.dll is not a complete implementation of B.dll. Is there a way to do this? Is there a way to statically link Foo.exe with A.lib, B.lib and Override.lib such that it will work without having to completely rebuild A.lib and B.lib to remove the __delcspec(dllexport)? Is there another option?

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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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  • How many users are sufficient to make a heavy load for web application

    - by galymzhan
    I have a web application, which has been suffering high load recent days. The application runs on single server which has 8-core Intel CPU and 4gb of RAM. Software: Drupal 5 (Apache 2, PHP5, MySQL5) running on Debian. After reaching 500 authenticated and 200 anonymous users (simultaneous), the application drastically decreases its performance up to total failure. The biggest load comes from authenticated users, who perform activities, causing insert/update/deletes on db. I think mysql is a bottleneck. Is it normal to slow down on such number of users? EDIT: I forgot to mention that I did some kind of profiling. I runned commands top, htop and they showed me that all memory was being used by MySQL! After some time MySQL starts to perform terribly slow, site goes down, and we have to restart/stop apache to reduce load. Administrators said that there was about 200 active mysql connections at that moment. The worst point is that we need to solve this ASAP, I can't do deep profiling analysis/code refactoring, so I'm considering 2 ways: my tables are MyIsam, I heard they use table-level locking which is very slow, is it right? could I change it to Innodb without worry? what if I take MySQL, and move it to dedicated machine with a lot of RAM?

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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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  • Problem with Active Record

    - by kshchepelin
    Hello everyone. Lets assume we have a User model. And user can plan some activities. The number of types of activities is about 50. All activities have common properties, such as start_time, end_time, user_id, etc. But each of them has some unique properties. Now we have each activity living in its own table in DB. And thats why we have such terrible sql queries like SELECT * FROM `first_activities_table` WHERE (`first_activity`.`id` IN (17,18)) SELECT * FROM `second_activities_table` WHERE (`second_activity`.`id` = 17) ..... SELECT * FROM `n_activities_table` WHERE (`n_activity`.`id` = 44) About 50 queries. That's terrible. There are different ways to solve this. Choose the activity type with the biggest number of properties, create the table 'Activities' and have STI model. But this way we must name our columns in uncomfortable way and often the record in that table would have some NULL fields. Also STI model, but having columns, common for all of activity types and some blob column with serialized properties. But we have to do some search on activities - there can be a problem. And serialization is quite slow. Please help me dealing with this. Maybe my problem has quite different solution that will fit my needs. Thanks for help.

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  • ASP .NET page runs slow in production

    - by Brandi
    I have created an ASP .NET page that works flawlessly and quickly from Visual Studio. It does a very large database read from a database on our network to load a gridview inside of an update panel. It displays progress in an Ajax modalpopupextender. Of course I don't expect it to be instant what with the large db reads, but it takes on the order of seconds, not on the order of minutes. This is all working great until I put it up on the server - it is very, VERY slow when I access it via the internet - takes several minutes to load the database information into the gridview. I'm baffled why it would not perform the exact same as it had from Visual Studio. (It is in release mode and I have taken off the debug flag) I have since been trying things like eliminating unneeded update panels and throwing out the ajax tool. Nothing has made it any faster on production. It is not the database as far as I know, since it has been consistently fast from my computer (from visual studio) and consistently slow from the server. I am wondering, where do I look next? Has anyone else had this problem before? Could this be caused by update panels or Ajax modalpopupextenders in different parts of the application? Why would the live behaviour differ so much from the localhost behaviour? Both the server with the ASP .NET page and the server with the database are servers on our network. I'm using Visual Studio 2008. Thank you in advance for any insight or advice.

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  • Excessive use of Inner Join for more than 3 tables

    - by Archangel08
    Good Day, I have 4 tables on my DB (not the actual name but almost similar) which are the ff: employee,education,employment_history,referrence employee_id is the name of the foreign key from employee table. Here's the example (not actual) data: **Employee** ID Name Birthday Gender Email 1 John Smith 08-15-2014 Male [email protected] 2 Jane Doe 00-00-0000 Female [email protected] 3 John Doe 00-00-0000 Male [email protected] **Education** Employee_ID Primary Secondary Vocation 1 Westside School Westshore H.S SouthernBay College 2 Eastside School Eastshore H.S NorthernBay College 3 Northern School SouthernShore H.S WesternBay College **Employment_History** Employee_ID WorkOne StartDate Enddate 1 StarBean Cafe 12-31-2012 01-01-2013 2 Coffebucks Cafe 11-01-2012 11-02-2012 3 Latte Cafe 01-02-2013 04-05-2013 Referrence Employee_ID ReferrenceOne Address Contact 1 Abraham Lincoln Lincoln Memorial 0000000000 2 Frankie N. Stein Thunder St. 0000000000 3 Peter D. Pan Neverland Ave. 0000000000 NOTE: I've only included few columns though the rest are part of the query. And below are the codes I've been working on for 3 consecutive days: $sql=mysql_query("SELECT emp.id,emp.name,emp.birthday,emp.pob,emp.gender,emp.civil,emp.email,emp.contact,emp.address,emp.paddress,emp.citizenship,educ.employee_id,educ.elementary,educ.egrad,educ.highschool,educ.hgrad,educ.vocational,educ.vgrad,ems.employee_id,ems.workOne,ems.estartDate,ems.eendDate,ems.workTwo,ems.wstartDate,ems.wendDate,ems.workThree,ems.hstartDate,ems.hendDate FROM employee AS emp INNER JOIN education AS educ ON educ.employee_id='emp.id' INNER JOIN employment_history AS ems ON ems.employee_id='emp.id' INNER JOIN referrence AS ref ON ref.employee_id='emp.id' WHERE emp.id='$id'"); Is it okay to use INNER JOIN this way? Or should I modify my query to get the results that I wanted? I've also tried to use LEFT JOIN but still it doesn't return anything .I didn't know where did I go wrong. You see, as I have thought, I've been using the INNER JOIN in correct manner, (since it was placed before the WHILE CLAUSE). So I couldn't think of what could've possible went wrong. Do you guys have a suggestion? Thanks in advance.

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  • Which are the RDBMS that minimize the server roundtrips? Which RDBMS are better (in this area) than

    - by user193655
    When the latency is high ("when pinging the server takes time") the server roundtrips make the difference. Now I don't want to focus on the roundtrips created in programming, but the roundtrips that occur "under the hood" in the DB engine, so the roundtrips that are 100% dependant on how the RDBMS is written itself. I have been told that FireBird has more roundtrips than MySQL. But this is the only information I know. I am currently supporting MS SQL but I'd like to change RDBMS (because I use Express Editions and in my scenario they are quite limiting from the performance point of view), so to make a wise choice I would like to include also this point into "my RDBMS comparison feature matrix" to understand which is the best RDBMS to choose as an alternative to MS SQL. So the bold sentence above would make me prefer MySQL to Firebird (for the roundtrips concept, not in general), but can anyone add informations? And MS SQL where is it located? Is someone able to "rank" the roundtrip performance of the main RDBMS, or at least: MS SQL, MySql, Postegresql, Firebird (I am not interested in Oracle since it is not free, and if I have to change I would change to a free RDBMS). Anyway MySql (as mentioned several times on stackoverflow) has a not clear future and a not 100% free license. So my final choice will probably dall on PostgreSQL or Firebird. Additional info: somehow you can answer my question by making a simple list like: MSSQL:3; MySQL:1; Firebird:2; Postgresql:2 (where 1 is good, 2 average, 3 bad). Of course if you can post some links where the roundtrips per RDBMSs are compared it would be great

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  • Hibernate 3.5.0 causes extreme performance problems

    - by user303396
    I've recently updated from hibernate 3.3.1.GA to hibernate 3.5.0 and I'm having a lot of performance issues. As a test, I added around 8000 entities to my DB (which in turn cause other entities to be saved). These entities are saved in batches of 20 so that the transactions aren't too large for performance reasons. When using hibernate 3.3.1.GA all 8000 entities get saved in about 3 minutes. When using hibernate 3.5.0 it starts out slower than with hibernate 3.3.1. But it gets slower and slower. At around 4,000 entities, it sometimes takes 5 minutes just to save a batch of 20. If I then go to a mysql console and manually type in an insert statement from the mysql general query log, half of them run perfect in 0.00 seconds. And half of them take a long time (maybe 40 seconds) or timeout with "ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction" from MySQL. Has something changed in hibernate's transaction management in version 3.5.0 that I should be aware of? The ONLY thing I changed to experience these unusable performance issues is replace the following hibernate 3.3.1.GA jar files: com.springsource.org.hibernate-3.3.1.GA.jar, com.springsource.org.hibernate.annotations-3.4.0.GA.jar, com.springsource.org.hibernate.annotations.common-3.3.0.ga.jar, com.springsource.javassist-3.3.0.ga.jar with the new hibernate 3.5.0 release hibernate3.jar and javassist-3.9.0.GA.jar. Thanks.

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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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  • Android Maven and Refresh Problem

    - by antonio Musella
    Hi all, i've a strange problem with maven and android I've 3 maven project and 2 normal java maven project divided in this manner : normal project : model project ... packaged as jar ... contains java Pojo Bean and Interface. Dao Project ... packaged as jar ... contains Db Logic - Depend on model Project Android Application Maven project ContentProvider ... packaged as apk ... contains ContentProviders only. Depends on Dao Project Editors ... packaged as apk ... contains only Editor, Depends on Dao project MainApp ... packaged as apk ... contains MyApp, Depends on DAO ... The Problem is that if i modify DAO Project , Then do a maven clean and maven install of all apk project, then run as Android Application within Eclipse, i don't see updated app on my Emulator. Nicely if i shut down my ubuntu workstation and restart it i can see The updated app on my Emulator. Do you know a solution for this issue ? thanks and regards

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  • Archiver Securing SQLite Data without using Encryption on iPhone

    - by Redrocks
    I'm developing an iphone app that uses Core Data with a SQLite data store and lots of images in the resource bundle. I want a "simple" way to obfuscate the file structure of the SQLite database and the image files to prevent the casual hacker/unscrupulous developer from gaining access to them. When the app is deployed, the database file and image files would be obfuscated. Upon launching the app it would read in and un-obfuscate the database file, write the un-obfuscated version to the users "tmp" directory for use by core data, and read/un-obfuscate image files as needed. I'd like to apply a simple algorithm to the files that would somehow scramble/manipulate the file data so that the sqlite database data isn't discernible when the db is opened in a text editor and so that neither is recognized by other applications (SQLite Manager, Photoshop, etc.) It seems, from the information I've read, that I could use NSFileManager, NSKeyedArchiver, and NSData to accomplish this but I'm not sure how to proceed. Been developing software for many years but I'm new to everything CocoaTouch, Mac and iPhone. Also never had to secure/encrypt my data so this is new. Any thoughts, suggestions, or links to solutions are appreciated.

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  • INSERT stored procedure does not work?

    - by vikitor
    Hello, I'm trying to make an insertion from one database called suspension to the table called Notification in the ANimals database. My stored procedure is this: ALTER PROCEDURE [dbo].[spCreateNotification] -- Add the parameters for the stored procedure here @notRecID int, @notName nvarchar(50), @notRecStatus nvarchar(1), @notAdded smalldatetime, @notByWho int AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON; -- Insert statements for procedure here INSERT INTO Animals.dbo.Notification values (@notRecID, @notName, @notRecStatus, null, @notAdded, @notByWho); END The null inserting is to replenish one column that otherwise will not be filled, I've tried different ways, like using also the names for the columns after the name of the table and then only indicate in values the fields I've got. I know it is not a problem of the stored procedure because I executed it from the sql server management studio and it works introducing the parameters. Then I guess the problem must be in the repository when I call the stored procedure: public void createNotification(Notification not) { try { DB.spCreateNotification(not.NotRecID, not.NotName, not.NotRecStatus, (DateTime)not.NotAdded, (int)not.NotByWho); } catch { return; } } It does not record the value in the database. I've been debugging and getting mad about this, because it works when I execute it manually, but not when I automatize the proccess in my application. Does anyone see anything wrong with my code? Thank you

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