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  • Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

    - by Umar
    Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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  • Stop 2 identical queries from executing almost simultaneously?

    - by James Simpson
    I have developed an AJAX based game where there is a bug caused (very remote, but in volume it happens at least once per hour) where for some reason two requests get sent to the processing page almost simultaneously (the last one I tracked, the requests were a difference of .0001 ms). There is a check right before the query is executed to make sure that it doesn't get executed twice, but since the difference is so small, the check hasn't finished before the next query gets executed. I'm stumped, how can I prevent this as it is causing serious problems in the game. Just to be more clear, the query is starting a new round in the game, so when it executes twice, it starts 2 rounds at the same time which breaks the game, so I need to be able to stop the script from executing if the previous round isn't over, even if that previous round started .0001 ms ago.

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  • Any disadvantages to this tagging approach

    - by donpal
    I have a table of tags ID tag --- ------ 1 tagt 2 tagb 3 tagz 4 tagn In my items table, I'm using those tags in serialized format, comma delimited ID field1 tags ---- ------ ----- 1 value1 tagt,tagb 2 value2 tagb 3 value3 tagb,tagn 4 value4 When I need to find items that have this tag, I plan to deserialize the tags. But I'm not actually sure how to do it, and if it's better to have a third table for associations instead between the tags and the items.

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  • How to perform COUNT() or COUNT(*)

    - by ninumedia
    I have a list of tags in a database. Ex: villan hero spiderman superman superman I wanted to obtain a sorted list of the tag names in ascending order and the number of times the unique tag appeared in the database. I wrote this code: Ex: SELECT hashtag.tag_name, COUNT( * ) AS number FROM hashtag GROUP BY hashtag.tag_name ORDER BY hashtag.tag_name ASC This yields the correct result: hero - 1 spiderman - 1 superman - 2 villan - 1 How can I obtain the full COUNT of this entire list. The answer should be 4 in this case because there are naturally 4 rows. I can't seem to get a correct COUNT() without the statement failing. Thanks so much for the help! :)

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  • Synchronise Database between servers via php [closed]

    - by Emmanuel
    Hi Guys, I'm needing to synchronise two mysql databases between different servers on a regular basis, by a client-initiated interface. I've been doing it by remote MYSQL connection, and adding the IP of the servers to the whitelist for MYSQL remote connections. Problem is however, that the client has a dynamic IP, so as soon as it changes they can no longer sync. So I'm trying to find an alternative way of synchronising the two databases via some sort of secure php script.

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  • Zend Framework table Relationships

    - by Uffo
    I have a table with over 4 million rows, I want to split this table in more tables, i.e one table with 50k rows. I also need to perform a search on these tables, whats the best way to do it? with JOIN, or? do you have some better ideas? Best Regards,

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  • How can I track the last location of a shipment effeciently using latest date of reporting?

    - by hash
    I need to find the latest location of each cargo item in a consignment. We mostly do this by looking at the route selected for a consignment and then finding the latest (max) time entered against nodes of this route. For example if a route has 5 nodes and we have entered timings against first 3 nodes, then the latest timing (max time) will tell us its location among the 3 nodes. I am really stuck on this query regarding performance issues. Even on few hundred rows, it takes more than 2 minutes. Please suggest how can I improve this query or any alternative approach I should acquire? Note: ATA= Actual Time of Arrival and ATD = Actual Time of Departure SELECT DISTINCT(c.id) as cid,c.ref as cons_ref , c.Name, c.CustRef FROM consignments c INNER JOIN routes r ON c.Route = r.ID INNER JOIN routes_nodes rn ON rn.Route = r.ID INNER JOIN cargo_timing ct ON c.ID=ct.ConsignmentID INNER JOIN (SELECT t.ConsignmentID, Max(t.firstata) as MaxDate FROM cargo_timing t GROUP BY t.ConsignmentID ) as TMax ON TMax.MaxDate=ct.firstata AND TMax.ConsignmentID=c.ID INNER JOIN nodes an ON ct.routenodeid = an.ID INNER JOIN contract cor ON cor.ID = c.Contract WHERE c.Type = 'Road' AND ( c.ATD = 0 AND c.ATA != 0 ) AND (cor.contract_reference in ('Generic','BP001','020-543-912')) ORDER BY c.ref ASC

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  • data recovery from unallocated harddisk partition

    - by user36007
    Hi, I accidentally deleted a partition which mainly served as space I put my data, labeled D: drive. The partition wasn't subsequently formatted though, following the delete incident. Obviously the D: drive doesn't show up as it usually does when I run Windows 7. In the "Computer Management", on clicking the Disk Management I clearly see the space is now labled as unallocated. question: How do I go about recovering my data. Perhaps what the effective data recovery software I can use to resolve this issue. Thanks

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  • data recovery from unallocated harddisk partition

    - by user42151
    Hi I accidentally deleted a partition which mainly served as space I put my data, labeled D: drive. The partition wasn't subsequently formatted though, following the delete incident. Obviously the D: drive doesn't show up as it usually does when I run Windows 7. In the "Computer Management", on clicking the Disk Management I clearly see the space is now labled as unallocated. question: How do I go about recovering my data. Perhaps what the effective data recovery software I can use to resolve this issue. Thanks

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  • data recovery from unallocated harddisk partition

    - by user36007
    Hi, I accidentally deleted a partition which mainly served as space I put my data, labeled D: drive. The partition wasn't subsequently formatted though, following the delete incident. Obviously the D: drive doesn't show up as it usually does when I run Windows 7. In the "Computer Management", on clicking the Disk Management I clearly see the space is now labled as unallocated. question: How do I go about recovering my data. Perhaps what the effective data recovery software I can use to resolve this issue. Thanks

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  • How to output JOINed tables?

    - by ilhan
    $id=(int)$_GET["id"]; $result = mysql_query("SELECT questionstable.*, categorytable.name FROM questionstable INNER JOIN categorytable ON categorytable.id = questionstable.category WHERE id=$id"); $row = mysql_fetch_assoc($result); Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in C:\Program Files\EasyPHP-5.3.4.0\www\scsoru.php on line 33

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  • Presenting Loading Data Warehouse Partitions with SSIS 2012 at SQL Saturday DC!

    - by andyleonard
    Join Darryll Petrancuri and me as we present Loading Data Warehouse Partitions with SSIS 2012 Saturday 8 Dec 2012 at SQL Saturday 173 in DC ! SQL Server 2012 table partitions offer powerful Big Data solutions to the Data Warehouse ETL Developer. In this presentation, Darryll Petrancuri and Andy Leonard demonstrate one approach to loading partitioned tables and managing the partitions using SSIS 2012, and reporting partition metrics using SSRS 2012. Objectives A practical solution for loading Big...(read more)

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  • Select nth percentile from MySQL

    - by mazin k.
    I have a simple table of data, and I'd like to select the row that's at about the 40th percentile from the query. I can do this right now by first querying to find the number of rows and then running another query that sorts and selects the nth row: select count(*) as `total` from mydata; select * from mydata order by `field` asc limit 37,1; Can I combine these two queries into a single query?

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  • SQL using sum to count results of multiple subqueries

    - by asdas
    I have a table with 2 columns: integer and var char. I am given only the integer values but need to do work on the var char (string) values. Given an integer, and a list of other integers (no overlap), I want to find the string for that single integer. Then I want to take that string and do the INSTR command with that string, and all the other strings for all the other integers. Then I want the sum of all the INSTR so the result is one number. So lets say I have int x, and list y=[y0, y1, y2]. I want to do 3 INSTR commands like SUM(INSTR(string for x, string for y0), INSTR(string for x, string for y1), INSTR(string for x, string for y2)) I think im going in the wrong direction, this is what I have. Im not good with sub queries. SELECT SUM ( SELECT INSTR ( SELECT string FROM pages WHERE int=? LIMIT 1, ( SELECT string FROM pages WHERE id=? OR id=? OR id=? LIMIT 3 ) ) )

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  • How to load the rest of the data in mysql in php

    - by user225269
    I have trouble figuring out how do I load the rest of the data in html. Here is my code: <?php $con = mysql_connect("localhost","root","nitoryolai123$%^"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("school", $con); $result = mysql_query("SELECT * FROM student WHERE IDNO='$_GET['id']'"); ?> <?php while ( $row = mysql_fetch_array($result) ) { ?> <table class="a" border="0" align="center" cellpadding="0" cellspacing="1" bgcolor="#D3D3D3"> <tr> <form name="formcheck" method="post" action="updateact.php" onsubmit="return formCheck(this);"> <td> <table border="0" cellpadding="3" cellspacing="1" bgcolor=""> <tr> <td colspan="16" height="25" style="background:#5C915C; color:white; border:white 1px solid; text-align: left"><strong><font size="2">Update Students</td> <tr> <td width="30" height="35"><font size="2">*I D Number:</td> <td width="30"><input name="idnum" onkeypress="return isNumberKey(event)" type="text" maxlength="5" id='numbers'/ value="<?php echo $_GET['id']; ?>"></td> </tr> <tr> <td width="30" height="35"><font size="2">*Year:</td> <td width="30"><input name="yr" onkeypress="return isNumberKey(event)" type="text" maxlength="5" id='numbers'/ value="<?php echo $row["YEAR"]; ?>"></td> this is the part where I am getting the error: mysql_select_db("school", $con); $result = mysql_query("SELECT * FROM student WHERE IDNO='$_GET['id']'"); ? What do you recommend that I could do so that I can also load the ID Numbers corresponding data into the other forms?

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  • How to optimize this user ranking query

    - by James Simpson
    I have 2 databases (users, userRankings) for a system that needs to have rankings updated every 10 minutes. I use the following code to update these rankings which works fairly well, but there is still a full table scan involved which slows things down with a few hundred thousand users. mysql_query("TRUNCATE TABLE userRankings"); mysql_query("INSERT INTO userRankings (userid) SELECT id FROM users ORDER BY score DESC"); mysql_query("UPDATE users a, userRankings b SET a.rank = b.rank WHERE a.id = b.userid"); In the userRankings table, rank is the primary key and userid is an index. Both tables are MyISAM (I've wondered if it might be beneficial to make userRankings InnoDB).

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  • "No database selected" even when db clearly selected

    - by Someone
    One of my webpages gets a recurring error: "No database selected", even though the DB is selected. Right about now it's a 50-50 chance whether the page will load just fine, or whether I receive this error. After one or two reloads, the page works again. I am including the exact same connection file on my other pages, and I don't have this problem. What could be the cause of this? I'm using ensim pro for webhosting. TIA.

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  • Help with grasping (INNER?) JOIN

    - by Greenie
    I'm having trouble building a query. I can do what I want in 3 different queries. SELECT id FROM table1 WHERE url LIKE '%/$downloadfile' put that in $url_id SELECT item_id FROM table2 WHERE rel_id = '$url_id'" put that in $item_id SELECT rel_id FROM table2 WHERE rel_id = '$item_id' AND field_id = '42'" put that in $user_id But from reading examples on joins and inner joins I think there's a more elegant way. I cant wrap my brain around writing a better query (but would like to) I can describe how it should go: table1 fields: id, url table2 fields item_id, rel_id, field_id I know the last part of table1.url (LIKE '%/$filename') with that I select table1.id. table1.id is equal to one entry in table2.rel_id. So get that and select the table2.item_id. In table2 there is another entry which has the same table2.item_id and it will have a table2.field_id = '42' And finally the value I need is the table2.rel_id where the table2.field_id was 42. I will fetch that value and put it in $user_id Can this be done with one query using joins/inner joins?

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  • How do I echo out something different when reached last row?

    - by Josh Brown
    I am wanting to not echo out the comma at the end of the echo after the last row. How can I do that? Here is my code: <?php header("Content-type: application/json"); echo '{"points":['; mysql_connect("localhost", "user", "password"); mysql_select_db("database"); $q = "SELECT venues.id, venues.lat, venues.lon, heat_indexes.temperature FROM venues, heat_indexes WHERE venues.id = heat_indexes.venue_id"; $res = mysql_query($q) or die(mysql_error()); while ($point = mysql_fetch_assoc($res)) { echo $point['lat'] . "," . $point['lon'] . "," . $point['temperature'] . ","; } mysql_free_result($res); echo ']}'; ?>

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  • SQL Saturday and Exploring Data Privacy

    - by Johnm
    I have been highly impressed with the growth of the SQL Saturday phenomenon. It seems that an announcement for a new wonderful event finds its way to my inbox on a daily basis. I have had the opportunity to attend the first of the SQL Saturday's for Tampa, Chicago, Louisville and recently my home town of Indianapolis. It is my hope that there will be many more in my future. This past weekend I had the honor of being selected to speak amid a great line up of speakers at SQL Saturday #82 in Indianapolis. My session topic/title was "Exploring Data Privacy". Below is a brief synopsis of my session: Data Privacy in a Nutshell        - Definition of data privacy        - Examples of personally identifiable data        - Examples of Sensitive data Laws and Stuff        - Various examples of laws, regulations and policies that influence the definition of data privacy        - General rules of thumb that encompasses most laws Your Data Footprint        - Who has personal information about you?        - What are you exchanging data privacy for?        - The amazing resilience of data        - The cost of data loss Weapons of Mass Protection       - Data classification       - Extended properties       - Database Object Schemas       - An extraordinarily brief introduction of encryption       - The amazing data professional  <-the most important point of the entire session! The subject of data privacy is one that is quickly making its way to the forefront of the mind of many data professionals. Somewhere out there someone is storing personally identifiable and other sensitive data about you. In some cases it is kept reasonably secure. In other cases it is kept in total exposure without the consideration of its potential of damage to you. Who has access to it and how is it being used? Are we being unnecessarily required to supply sensitive data in exchange for products and services? These are just a few questions on everyone's mind. As data loss events of grand scale hit the headlines in a more frequent succession, the level of frustration and urgency for a solution increases. I assembled this session with the intent to raise awareness of sensitive data and remind us all that we, data professionals, are the ones who have the greatest impact and influence on how sensitive data is regarded and protected. Mahatma Gandhi once said "Be the change you want to see in the world." This is guidance that I keep near to my heart as I approached this topic of data privacy.

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  • I could use some help with my SQL command

    - by SuperSpy
    I've got a database table called 'mesg' with the following structure: receiver_id | sender_id | message | timestamp | read Example: 2 *(«me)* | 6 *(«nice girl)* | 'I like you, more than ghoti' | yearsago | 1 *(«seen it)* 2 *(«me)* | 6 *(«nice girl)* | 'I like you, more than fish' | now | 1 *(«seen it)* 6 *(«nice girl)* | 2 *(«me)* | 'Hey, wanna go fish?' | yearsago+1sec | 0 *(«she hasn't seen it)* It's quite a tricky thing that I want to achieve. I want to get: the most recent message(=ORDER BY time DESC) + 'contact name' + time for each 'conversation'. Contact name = uname WHERE uid = 'contact ID' (the username is in another table) Contact ID = if(sessionID*(«me)*=sender_id){receiver_id}else{sender_id} Conversation is me = receiver OR me = sender For example: From: **Bas Kreuntjes** *(« The message from bas is the most recent)* Hey $py, How are you doing... From: **Sophie Naarden** *(« Second recent)* Well hello, would you like to buy my spam? ... *(«I'll work on that later >p)* To: **Melanie van Deijk** *(« My message to Melanie is 3th)* And? Did you kiss him? ... That is a rough output. QUESTION: Could someone please help me setup a good SQL command. This will be the while loup <?php $sql = "????"; $result = mysql_query($sql); while($fetch = mysql_fetch_assoc($result)){ ?> <div class="message-block"> <h1><?php echo($fetch['uname']); ?></h1> <p><?php echo($fetch['message']); ?></p> <p><?php echo($fetch['time']); ?></p> </div> <?php } ?> I hope my explanation is good enough, if not, please tell me. Please don't mind my English, and the Dutch names (I am Dutch myself) Feel free to correct my English UPDATE1: Best I've got until now: But I do not want more than one conversation to show up... u=user table m=message table SELECT u.uname, m.message, m.receiver_uid, m.sender_uid, m.time FROM m, u WHERE (m.receiver_uid = '$myID' AND u.uid = m.sender_uid) OR (m.sender_uid = '$myID' AND u.uid = m.receiver_uid) ORDER BY time DESC;

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  • SQL SELECT across two tables

    - by Brett Spurrier
    Hi there, I am a little confused as to how to approach this SQL query. I have two takes (equal number of records), and I would like to return a column with which is the division between the two. In other words, here is my not-working-correctly query: SELECT( (SELECT v FROM Table1) / (SELECT DotProduct FROM Table2) ); How would I do this? All I want it a column where each row equals the same row in Table1 divided by the same row in Table2. The resulting table should have the same number of rows, but I am getting something with a lot more rows than the original two tables. I am at a complete loss. Any advice?

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  • PHP - Retrieve Data From mySQL Server

    - by Kevin
    Hello, Does anyone know how to retrieve a piece of data and display the results in php file? A similar query that I would enter is something like this: SELECT 'email' FROM 'users' WHERE 'username' = 'bob' Thus, the result would be just the email. Thanks, Kevin

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  • A better way to delete a list of elements from multiple tables

    - by manyxcxi
    I know this looks like a 'please write the code' request, but some basic pointer/principles for doing this the right way should be enough to get me going. I have the following stored procedure: CREATE PROCEDURE `TAA`.`runClean` (IN idlist varchar(1000)) BEGIN DECLARE EXIT HANDLER FOR NOT FOUND ROLLBACK; DECLARE EXIT HANDLER FOR SQLEXCEPTION ROLLBACK; DECLARE EXIT HANDLER FOR SQLWARNING ROLLBACK; START TRANSACTION; DELETE FROM RunningReports WHERE run_id IN (idlist); DELETE FROM TMD_INDATA_INVOICE WHERE run_id IN (idlist); DELETE FROM TMD_INDATA_LINE WHERE run_id IN (idlist); DELETE FROM TMD_OUTDATA_INVOICE WHERE run_id IN (idlist); DELETE FROM TMD_OUTDATA_LINE WHERE run_id IN (idlist); DELETE FROM TMD_TEST WHERE run_id IN (idlist); DELETE FROM RunHistory WHERE id IN (idlist); COMMIT; END $$ It is called by a PHP script to clean out old run history. It is not particularly efficient as you can see and I would like to speed it up. The PHP script gathers the ids to remove from the tables with the following query: $query = "SELECT id, stop_time FROM RunHistory WHERE config_id = $configId AND save = 0 AND NOT(stop_time IS NULL) ORDER BY stop_time"; It keeps the last five run entries and deletes all the rest. So using this query to bring back all the IDs, it determines which ones to delete and keeps the 'newest' five. After gathering the IDs it sends them to the stored procedure to remove them from the associated tables. I'm not very good with SQL, but I ASSUME that using an IN statement and not joining these tables together is probably the least efficient way I can do this, but I don't know enough to ask anything but "how do I do this better?" If possible, I would like to do this all in my stored procedure using a query to gather all the IDs except for the five 'newest', then delete them. Another twist, run entries can be marked save (save = 1) and should not be deleted. The RunHistory table looks like this: CREATE TABLE `TAA`.`RunHistory` ( `id` int(11) NOT NULL auto_increment, `start_time` datetime default NULL, `stop_time` datetime default NULL, `config_id` int(11) NOT NULL, [...] `save` tinyint(1) NOT NULL default '0', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;

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  • When and why are certain data structures used in the context of web development?

    - by Ein Doofus
    While browsing around the MSDN I came across: http://msdn.microsoft.com/en-us/library/aa287104%28v=vs.71%29 which lists various data structures such as: Queues Stacks Hashtables Binary Trees Binary Search Trees Graphs (I believe there are also Lists) and I was hoping to get a high-level overview of when these various data structures can be used in the broad context of web development, and when used, why one data structure is generally used instead of any other one.

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