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• How can I integrate advanced computations into a database field?

  - by ciclistadan

  My biological research involves the measurement of a cellular structure as it changes length throughout the course of observation (capturing images every minute for several hours). As my data sets have become larger I am trying to store them in an Access database, from which I would like to perform various queries about their changes in size. I know that the SELECT statement can incorporate some mathematical permutations, but I have been unable to incorporate many of my necessary calculations (probably due to my lack of knowledge). For example, one calculation involves determining the rate of change during specifically defined periods of growth. This calculation is entirely dependent on the raw data saved in the table, therefore I didn't this it would be appropriate to just calculate it in excel prior to entry into the field. So my question is, what would be the most appropriate method of performing this calculation. Should I attempt to string together a huge SELECT calculation in my QUERY, or is there a way to use another language (I know perl?) which can be called to populate the new query field? I'm not looking for someone to write the code, just where is it appropriate to incorporate each step. Also, I am currently using Office Access but would be interested in any mySQL answers as I may be moving to this platform at a later date. Thanks all!

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• suppose there is a class which contains 4 data fields.i have to read these value from xml file and s

  - by SunilRai86

  suppose there is a class which contains 4 fields.i have to read these value from xml file and set that value to fields the xml file is like that <Root> <Application > <AppName>somevalue</AppName> <IdMark>somevalue</IdMark> <ClassName>ABC</ClassName> <ExecName>XYZ</ExecName> </Application> <Application> <AppName>somevalue</AppName> <IdMark>somevalue</IdMark> <ClassName>abc</ClassName> <ExecName>xyz</ExecName> </Application> </Root> now i have to read all the values from xml file and set each value to particular fields. i hav done reading of the xml file and i saved the retrieved value in arraylist. the code is like that public class CXmlFileHook { string appname; string classname; string idmark; string execname; string ctor; public CXmlFileHook() { this.appname = "Not Set"; this.idmark = "Not Set"; this.classname = "Not Set"; this.execname = "Not Set"; this.ctor = "CXmlFileHook()"; } public void readFromXmlFile(string path) { XmlTextReader oRreader = new XmlTextReader(@"D:\\Documents and Settings\\sunilr\\Desktop\\MLPACK.xml"); //string[] strNodeValues = new string[4] { "?","?","?","?"}; ArrayList oArrayList = new ArrayList(); while (oRreader.Read()) { if (oRreader.NodeType == XmlNodeType.Element) { switch (oRreader.Name) { case "AppName": oRreader.Read(); //strNodeValues[0] =oRreader.Value; oArrayList.Add(oRreader.Value); break; case "IdMark": oRreader.Read(); //strNodeValues[1] = oRreader.Value; oArrayList.Add(oRreader.Value); break; case "ClassName": oRreader.Read(); //strNodeValues[2] = oRreader.Value; oArrayList.Add(oRreader.Value); break; case "ExecName": oRreader.Read(); //strNodeValues[3] = oRreader.Value; oArrayList.Add(oRreader.Value); break; } } } Console.WriteLine("Reading from arraylist"); Console.WriteLine("-------------------------"); for (int i = 0; i < oArrayList.Count; i++) { //Console.WriteLine("Reading from Sting[]"+ strNodeValues[i]); Console.WriteLine(oArrayList[i]); } //this.appname = strNodeValues[0]; //this.idmark = strNodeValues[1]; //this.classname = strNodeValues[2]; //this.execname = strNodeValues[3]; this.appname = oArrayList[0].ToString(); this.idmark = oArrayList[1].ToString(); this.classname = oArrayList[2].ToString(); this.execname = oArrayList[3].ToString(); } static string vInformation; public void showCurrentState(string path) { FileStream oFileStream = new FileStream(path, FileMode.Append, FileAccess.Write); StreamWriter oStreamWriter = new StreamWriter(oFileStream); oStreamWriter.WriteLine("****************************************************************"); oStreamWriter.WriteLine(" Log File "); oStreamWriter.WriteLine("****************************************************************"); CXmlFileHook oFilehook = new CXmlFileHook(); //Type t = Type.GetType(this._classname); //Type t = typeof(CConfigFileHook); DateTime oToday = DateTime.Now; vInformation += "Logfile created on : "; vInformation += oToday + Environment.NewLine; vInformation += "Public " + Environment.NewLine; vInformation += "----------------------------------------------" + Environment.NewLine; vInformation += "Private " + Environment.NewLine; vInformation += "-----------------------------------------------" + Environment.NewLine; vInformation += "ctor = " + this.ctor + Environment.NewLine; vInformation += "appname = " + this.appname + Environment.NewLine; vInformation += "idmark = " + this.idmark + Environment.NewLine; vInformation += "classname = " + this.classname + Environment.NewLine; vInformation += "execname = " + this.execname + Environment.NewLine; vInformation += "------------------------------------------------" + Environment.NewLine; vInformation += "Protected" + Environment.NewLine; vInformation += "------------------------------------------------" + Environment.NewLine; oStreamWriter.WriteLine(vInformation); oStreamWriter.Flush(); oStreamWriter.Close(); oFileStream.Close(); } } here i set set the fields according to arraylist index but i dont want is there any another solution for this....

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• Angularjs showin time portion from date time

  - by J. Davidson

  Hi I have following input which displays datetime <div ng-repeat="item in items"> <input type="text" ng-model="item.name" /> <input ng-model="item.time" /> </div> The issue i have is that time is in following format. "2002-11-28T14:00:00Z" I want to just display the time portion. For which I would have to apply filter date: 'hh:mm a' I tried ng-model="labor.start_time | date: 'hh:mm a'" Please let me know how i can show only time portion in input box showin time only. I cant use span tag as the time a user can change so have to show in input tag. Thanks

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• Java - multithreaded access to a local value store which is periodically cleared

  - by Telax

  I'm hoping for some advice or suggestions on how best to handle multi threaded access to a value store. My local value storage is designed to hold onto objects which are currently in use. If the object is not in use then it is removed from the store. A value is pumped into my store via thread1, its entry into the store is announced to listeners, and the value is stored. Values coming in on thread1 will either be totally new values or updates for existing values. A timer is used to periodically remove any value from the store which is not currently in use and so all that remains of this value is its ID held locally by an intermediary. Now, an active element on thread2 may wake up and try to access a set of values by passing a set of value IDs which it knows about. Some values will be stored already (great) and some may not (sadface). Those values which are not already stored will be retrieved from an external source. My main issue is that items which have not already been stored and are currently being queried for may arrive in on thread1 before the query is complete. I'd like to try and avoid locking access to the store whilst a query is being made as it may take some time.

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• Win32_Product InstallLocation (error)

  - by andrew

  in C#, i'm trying to get some properties from the instances of Win32_Product, but i seem to have an error saying "Object reference not set to an instance of an object." here's the code: class Package { public string productName; public string installDate; public string installLocation; } class InstalledPackages { public static List<Package> get() { List<Package> packages = new List<Package>(); string query = "SELECT * FROM Win32_Product"; ManagementScope oMs = new ManagementScope(); ObjectQuery oQuery = new ObjectQuery(query); ManagementObjectSearcher oSearcher = new ManagementObjectSearcher(oMs, oQuery); ManagementObjectCollection installedPackages = oSearcher.Get(); foreach (ManagementObject package in installedPackages) { Package p = new Package(); p.productName = package["Name"].ToString(); p.installLocation = package["InstallLocation"].ToString(); p.installDate = package["InstallDate"].ToString(); packages.Add(p); } return packages; } } the exception appears when it gets to p.installLocation = package["InstallLocation"].ToString(); also, i get one if i try to do p.installLocation = package["InstallDate2"].ToString(); if i'm asking for InstallDate it works. (i'm using Windows 7 Ultimate x64)

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• Programming Practice

  - by deepti

  public DataTable UserUpdateTempSettings(int install_id, int install_map_id, string Setting_value,string LogFile) { SqlConnection oConnection = new SqlConnection(sConnectionString); DataSet oDataset = new DataSet(); DataTable oDatatable = new DataTable(); SqlDataAdapter MyDataAdapter = new SqlDataAdapter(); try { oConnection.Open(); cmd = new SqlCommand("SP_HOTDOC_PRINTTEMPLATE_PERMISSION", oConnection); cmd.Parameters.Add(new SqlParameter ("@INSTALL_ID", install_id)); cmd.Parameters.Add(new SqlParameter ("@INSTALL_MAP_ID", install_map_id)); cmd.Parameters.Add(new SqlParameter("@SETTING_VALUE", Setting_value)); if (LogFile != "") { cmd.Parameters.Add(new SqlParameter("@LOGFILE",LogFile)); } cmd.CommandType = CommandType.StoredProcedure; MyDataAdapter.SelectCommand = cmd; cmd.ExecuteNonQuery(); MyDataAdapter.Fill(oDataset); oDatatable = oDataset.Tables[0]; return oDatatable; } catch (Exception ex) { Utils.ShowError(ex.Message); return oDatatable; } finally { if ((oConnection.State != ConnectionState.Closed) || (oConnection.State != ConnectionState.Broken)) { oConnection.Close(); } oDataset = null; oDatatable = null; oConnection.Dispose(); oConnection = null; } } i have used execute non query.. normally its not used with data adapter... if iam not using its giving me error.. is it bad programming practice to use execute non query with data adapter

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• How do I unpack bits from a structure's stream_data in c code?

  - by Chelp

  Ex. typedef struct { bool streamValid; dword dateTime; dword timeStamp; stream_data[800]; } RadioDataA; Ex. Where stream_data[800] contains: **Variable** **Length (in bits)** packetID 8 packetL 8 versionMajor 4 versionMinor 4 radioID 8 etc.. I need to write: void unpackData(radioDataA *streamData, MA_DataA *maData) { //unpack streamData (from above) & put some of the data into maData //How do I read in bits of data? I know it's by groups of 8 but I don't understand how. //MAData is also a struct. }

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• Automatically Persisting a Complex Java Object

  - by VeeArr

  For a project I am working on, I need to persist a number of POJOs to a database. The POJOs class definitions are sometimes highly nested, but they should flatten okay, as the nesting is tree-like and contains no cycles (and the base elements are eventually primitives/Strings). It is preferred that the solution used create one table per data type and that the tables will have one field per primitive member in the POJO. Subclassing and similar problems are not issues for this particular project. Does anybody know of any existing solutions that can: Automatically generate a CREATE TABLE definition from the class definition Automatically generate a query to persist an object to the database, given an instance of the object Automatically generate a query to retrieve an object from the database and return it as a POJO, given a key. Solutions that can do this with minimum modifications/annotions to the class files and minimum external configuration are preferred. Example: Java classes //Class to be persisted class TypeA { String guid; long timestamp; TypeB data1; TypeC data2; } class TypeB { int id; int someData; } class TypeC { int id; int otherData; } Could map to CREATE TABLE TypeA ( guid CHAR(255), timestamp BIGINT, data1_id INT, data1_someData INT, data2_id INt, data2_otherData INT ); Or something similar.

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• Client-server application between two computers in the same network (using boost::asio)

  - by Edwin

  I'm trying to set up a basic communication between my desktop PC and my laptop (latter one using wireless connection) both being in the same network, using the boost::asio tutorials: synchronous client and synchronous server (in c++). When I run both the server and client on the same machine (using the localhost and the datetime port as parameters), it works splendidly. But if I try to set up the laptop as server (tested it with netstat -anb from the command prompt, it is indeed running and listening to port 13 as it's supposed to, and I even deactivated the firewall to make sure it doesn't cause any problems), I cannot connect to it with the client (set up on the PC), no matter what IP I tried (localhost, and basically any IPs that ipconfig -all gave me). So no matter what I tried, I cannot find the correct address that which the client can use to connect to the server. Could anyone help me please?

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• Grouping by property value and writing group members

  - by Will S

  I need to group the following list by the department value but am having trouble with the LINQ syntax. Here's my list of objects: var people = new List<Person> { new Person { name = "John", department = new List<fields> {new fields { name = "department", value = "IT"}}}, new Person { name = "Sally", department = new List<fields> {new fields { name = "department", value = "IT"}}}, new Person { name = "Bob", department = new List<fields> {new fields { name = "department", value = "Finance"}}}, new Person { name = "Wanda", department = new List<fields> {new fields { name = "department", value = "Finance"}}}, }; I've toyed around with grouping. This is as far as I've got: var query = from p in people from field in p.department where field.name == "department" group p by field.value into departments select new { Department = departments.Key, Name = departments }; So can iterate over the groups, but not sure how to list the Person names - foreach (var department in query) { Console.WriteLine("Department: {0}", department.Department); foreach (var foo in department.Department) { // ?? } } Any ideas on what to do better or how to list the names of the relevant departments?

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• What constitutes explicit creation of entities in LINQ to SQL? What elegant "solutions" are there to

  - by Marcelo Zabani

  Hi SO, I've been having problems with the rather famous "Explicit construction of entity type '##' in query is not allowed." error. Now, for what I understand, this exists because if explicit construction of these objects were allowed, tracking changes to the database would be very complicated. So I ask: What constitutes the explicit creation of these objects? In other terms: Why can I do this: Product foo = new Product(); foo.productName = "Something"; But can't do this: var bar = (from item in myDataContext.Products select new Product { productName = item.productName }).ToList(); I think that when running the LINQ query, some kind of association is made between the objects selected and the table rows retrieved (and this is why newing a Product in the first snippet of code is no problem at all, because no associations were made). I, however, would like to understand this a little more in depth (and this is my first question to you, that is: what is the difference from one snippet of code to another). Now, I've heard of a few ways to attack this problem: 1) The creation of a class that inherits the linq class (or one that has the same properties) 2) Selecting anonymous objects And this leads me to my second question: If you chose one of the the two approaches above, which one did you choose and why? What other problems did your approach introduce? Are there any other approaches?

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• How to first get different related values from diferent SQL tables (PHP)

  - by Ole Jak

  I am triig to fill options list. I have 2 tables USERS and STREAMS I vant to get all streams and get names of users assigned to that streams. Users consists of username and id Streams consists of id, userID, streamID I try such code: <?php global $connection; $query = "SELECT * FROM streams "; $streams_set = mysql_query($query, $connection); confirm_query($streams_set); $streams_count = mysql_num_rows($streams_set); while ($row = mysql_fetch_array($streams_set)){ $userid = $row['userID']; global $connection; $query2 = "SELECT email, username "; $query2 .= "FROM users "; $query2 .= "WHERE id = '{$userid}' "; $qs = mysql_query($query2, $connection); confirm_query($qs); $found_user = mysql_fetch_array($qs); echo ' <option value="'.$row['streamID'].'">'.$row['userID'].$found_user.'</option> '; } ?> But it does not return USER names from DB=( So what shall I do to this code to see usernames as "options" text?

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• Optional mix of filter parameters in a search the Rails way.

  - by GSP

  I've got a simple list page with a couple of search filters status which is a simple enumeration and a test query which I want to compare against both the title and description field of my model. In my controller, I want to do something like this: def index conditions = {} conditions[:status] = params[:status] if params[:status] and !params[:status].empty? conditions[???] = ["(descr = ? or title = ?)", params[:q], params[:q]] if params[:q] and !params[:q].empty? @items = Item.find(:all, :conditions => conditions) end Unfortunately, it doesn't look like I can mix the two types of conditions (the hash and the paramatized version). Is there a "Rails Way" of doing this or do I simply have to do something awful like this: has_status = params[:status] and !params[:status].empty? has_text = params[:q] and !params[:q].empty? if has_status and !has_text # build paramatized condition with just the status elsif has_text and !has_status # build paramatized condition with just the text query elsif has_text and has_status # build paramatized condition with both else # build paramatized condition with neither end I'm migrating from Hibernate and Criteria so forgive me if I'm not thinking of this correctly... Environment: Rails 2.3.4

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• Obtaining a timestamp every minute from a database

  - by soumen

  This is my table structure: +------------+-----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------+-----------+------+-----+---------+-------+ | uid | char(255) | NO | MUL | NULL | | | cid | char(255) | NO | MUL | NULL | | | ip_address | char(15) | NO | | NULL | | | user_agent | char(255) | YES | | NULL | | | open_date | datetime | NO | MUL | NULL | | | referrer | char(255) | YES | | NULL | | | environ | text | YES | | NULL | | | country | char(255) | NO | MUL | NULL | | +------------+-----------+------+-----+---------+-------+ I want to get a timestamp every minute within a range. select DATE_ADD(open_date,interval 1 minute) as m from open_track.camp_open where open_date between "2009-05-13 00:00:00" and "2009-05-13 23:59:59" limit 10; outputs +---------------------+ | m | +---------------------+ | 2009-05-13 00:01:01 | | 2009-05-13 00:01:02 | | 2009-05-13 00:01:03 | | 2009-05-13 00:01:03 | | 2009-05-13 00:01:04 | | 2009-05-13 00:01:05 | | 2009-05-13 00:01:06 | | 2009-05-13 00:01:08 | | 2009-05-13 00:01:08 | | 2009-05-13 00:01:09 | +---------------------+ Please advise me.

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• login script in php using session variables

  - by kracekumar

  ? username: '; } else { $user=$_POST['user']; $query="select name from login where name='$user'"; $result=mysql_query($query) or die(mysql_error()); $rows=mysql_num_rows($result)or die(mysql_error()); session_start(); //echo "results"; $username=mysql_fetch_array($result) or die(mysql_error()); $fields=mysql_num_fields($result) or die(mysql_error()); echo "username:$username[0]"; $_SESSION['username']=$username[0]; $sesion_username=$_SESSION['username']; //echo "rows:$rows"." "."fields:$fields"; echo""."username:$sesion_username"; } ? i wanted to create a site where user can login and upload their details depending on their user name have stored their details in a database,the problem i am facing is two people 'a' and 'b' login one after other session_variable $_SESSION['username'] will have 'b's' username ,so i can't display 'a's' details now. . . . what i want to achieve is when a user logins in i want to store his name and other details in session variable and navigate him according and display his details

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• Please help!! C# Anonymous and returning filtered properties with JSON

  - by Raj Aththanayake

  What is the best way to return only few properties to JSON Result from a collection IEnumerable? Department object has 7properties I only need to 2 of them in client. Can I do this using C# anonymous types? public class Department { public string DeptId { get; set; } public string DeptName { get; set; } public string DeptLoc1 { get; set; } public string DeptLoc2 { get; set; } public string DeptMgr { get; set; } public string DeptEmp { get; set; } public string DeptEmp2 { get; set; } } [HttpGet] public JsonResult DepartmentSearch(string query) { IEnumerable<Department> depts = DeptSearchService.GetDepartments(query); //Department object has 15 properties, I ONLY need 2 (DeptID and DeptName) in the view via returns JSON result) return Json(depts, JsonRequestBehavior.AllowGet); // I don’t want all the properties of a department object }

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• MySql: Is it reasonable to use 'view' or I would better denormalize my DB?

  - by Budda

  There is 'team_sector' table with following fields: Id, team_id, sect_id, size, level It contains few records for each 'team' entity (referenced with 'team_id' field). Each record represent sector of team's stadium (totally 8 sectors). Now it is necessary to implement few searches: by overall stadium size (SUM(size)); the best quality (SUM(level)/COUNT(*)). I could create query something like this: SELECT TS.team_id, SUM(TS.size) as OverallSize, SUM(TS.Level)/COUNT(TS.Id) AS QualityLevel FROM team_sector GROUP BY team_id ORDER BY OverallSize DESC / ORDER BY QualityLevel DESC But my concern here is that calculation for each team will be done each time on query performed. It is not too big overhead (at least now), but I would like to avoid performance issues later. I see 2 options here. The 1st one is to create 2 additional fields in 'team' table (for example) and store there OverallSize and QualityLevel fields. If information if 'sector' table is changed - update those table too (probably would be good to do that with triggers, as sector table doesn't change too often). The 2nd option is to create a view that will provide required data. The 2nd option seems much easier for me, but I don't have a lot of experience/knowledge of work with views. Q1: What is the best option from your perspective here and why? Probably you could suggest other options? Q2: Can I create view in such way that it will do calculations rarely (at least once per day)? If yes - how? Q3: Is it reasonable to use triggers for such purpose (1st option). P.S. MySql 5.1 is used, overall number of teams is around 1-2 thousand, overall number of records in sector table - overall 6-8 thousand. I understand, those numbers are pretty small, but I would like to implement the best practice here.

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• Bind to a collection's view and just call ToString()

  - by womp

  I'm binding a GridView to a collection of objects that look like this: public class Transaction { public string PersonName { get; set; } public DateTime TransactionDate { get; set; } public MoneyCollection TransactedMoney { get; set;} } MoneyCollection simply inherits from ObservableCollection<T>, and is a collection of MyMoney type object. In my GridView, I just want to bind a column to the MoneyCollection's ToString() method. However, binding it directly to the TransactedMoney property makes every entry display the text "(Collection)", and the ToString() method is never called. I understand that it is binding to the collection's default view. So my question is - how can I make it bind to the collection in such a way that it calls the ToString() method on it? This is my first WPF project, so I know this might be a bit noobish, but pointers would be very welcome.

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• what is the accepted naming convention for int, string, array, list, object, etc...

  - by RJ

  The company I work for now uses a set naming convention for their C# variables such as iSomeName for int, sSomeName for string, aSomeName for arrays, bSomeName for boolean, dSomeName for datetime and so on. My previous employer did not use the i, s, a, b and d prefixes and just named the variables a good understandable name. My impression is that these prefixes lost favor a while ago and from what I read it is not the current trend. It seems fine to me either way as long as the variable is descriptive enough to understand what it is doing but I was wondering what the now-a-day accepted practice is for naming variables?

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• Read video information(date created)?

  - by Lynx

  In window, i can get the date created of the video from properties(right click). I have a few idea on this but i dont know how to do it. 1. Get the video information directly from video(like in windows), 2. By extracting the video name to get the date created(The video's name is in date format, which is the time it created). And i also using taglib-sharp to get the video duration and resolution, but i cant find any sample code on how to get the video creation date. Note: video name in date format - example, 20121119_125550.avi Edit Found this code and so far its working string fileName = Server.MapPath("//video//20121119_125550.avi"); FileInfo fileInfo = new FileInfo(fileName); DateTime creationTime = fileInfo.CreationTime; Output: 2012/11/19 12:55:50 For the file's name, i will add another string in name. For example User1-20121119_125550.avi.avi, so it will get complicated after that.

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• Questions about shifting from mysql to PDO

  - by Scarface

  Hey guys I have recently decided to switch all my current plain mysql queries performed with php mysql_query to PDO style queries to improve performance, portability and security. I just have some quick questions for any experts in this database interaction tool Will it prevent injection if all statements are prepared? (I noticed on php.net it wrote 'however, if other portions of the query are being built up with unescaped input, SQL injection is still possible' I was not exactly sure what this meant). Does this just mean that if all variables are run through a prepare function it is safe, and if some are directly inserted then it is not? Currently I have a connection at the top of my page and queries performed during the rest of the page. I took a look at PDO in more detail and noticed that there is a try and catch procedure for every query involving a connection and the closing of that connection. Is there a straightforward way to connecting and then reusing that connection without having to put everything in a try or constantly repeat the procedure by connecting, querying and closing? Can anyone briefly explain in layman's terms what purpose a set_exception_handler serves? I appreciate any advice from any more experienced individuals.

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• Very weird jquery/json problem...

  - by Scarface

  Hey guys I have finally located the cause of this problem...I just have no idea how to fix it and why it is happening. I have a jquery getjson function and it returns 0 results every 2-5 clicks on new topics or refreshes. For some reason if I change my query to sort results by ASC it always returns results and much quicker, but this poses a problem since I need results by DESC. If anyone has any ideas, I would greatly appreciate it because I am dumbfounded at this point. Here is my query but I need it by DESC SELECT time, user, message FROM comments WHERE topic_id='$topic_id' ORDER BY time ASC LIMIT 10 $.getJSON(files+"comments.php?action=view&load=initial&topic_id="+topic_id+"&t=" + (new Date()), function(json) { if(json.length) { for(i=0; i < json.length; i++) { $('#comment-list').prepend(prepare(json[i])); $('#list-' + count).fadeIn(1500); } } }); I return results like so while($row = mysql_fetch_array($res)){ $data[] = $row; } $out = json_encode($data); print $out;

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• Hive performance increase

  - by Sagar Nikam

  I am dealing with a database (2.5 GB) having some tables only 40 row to some having 9 million rows data. when I am doing any query for large table it takes more time. I want results in less time small query on table which have 90 rows only-- hive> select count(*) from cidade; Time taken: 50.172 seconds hdfs-site.xml <configuration> <property> <name>dfs.replication</name> <value>3</value> <description>Default block replication. The actual number of replications can be specified when the file is created. The default is used if replication is not specified in create time. </description> </property> <property> <name>dfs.block.size</name> <value>131072</value> <description>Default block replication. The actual number of replications can be specified when the file is created. The default is used if replication is not specified in create time. </description> </property> </configuration> does these setting affects performance of hive? dfs.replication=3 dfs.block.size=131072 can i set it from hive prompt as hive>set dfs.replication=5 Is this value remains for a perticular session only ? or Is it better to change it in .xml file ?

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• r -- finding difference between business days

  - by acesnap

  I have several years of data (only for business days (no weekends or holidays)) in an [r] data frame and would like to find the difference between the data on the 2nd and 5th business day of each month. So the solution needs to go thru the list, determine the 2nd and 5th business day, get the data for the corresponding dates and then find the difference. the data looks like: 1/19/1990 1.22 1/20/1990 1.25 1/23/1990 1.26 (Gap in date is weekend) ... 2/1/1990 1.34 2/2/1990 1.36 2/5/1990 1.22 (Gap in date is weekend) I have tried using dateTime() but it doesn't handicap for weekends and holidays. Any suggestions would be appreciated, thanks.

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• Why does this sql statement keep saying it is a boolean and not a parameter? (php/Mysql)

  - by ggfan

  In this statement, I am trying to see if there if the latest posting in the database that has the exact same title, price, city, state, detail. If there is, then it would say to the user that the exact post has been already made; if not then insert the posting into the dbc. (This is one type of check so that users can't accidentally post twice. This may not be the best check, but this statement error is annoying me, so I want it to work :)) Why won't this sql work? I think it's not letting the title=$title and not getting the value in the $title... ERROR: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in postad.php on line 365 //there is a form that users fill out that has title, price, city, etc <form> blah blah </form> //if users click submit, then does all the checks and if all okay, insert to dbc if (isset($_POST['submit'])) { // Grab the pposting data from the POST and gets rid of any funny stuff $title = mysqli_real_escape_string($dbc, trim($_POST['title'])); $price = mysqli_real_escape_string($dbc, trim($_POST['price'])); $city = mysqli_real_escape_string($dbc, trim($_POST['city'])); $state = mysqli_real_escape_string($dbc, trim($_POST['state'])); $detail = mysqli_real_escape_string($dbc, trim($_POST['detail'])); if (!is_numeric($price) && !empty($price)) { echo "<p class='error'>The price can only be numbers. No special characters, etc</p>"; } //Error problem...won't let me set title=$title, detail=$detail, etc. //this statement after all the checks so that none of the variables are empty $query="Select * FROM posting WHERE user_id={$_SESSION['user_id']} AND title=$title AND price=$price AND city=$city AND state=$state AND detail=$detail"; $data = mysqli_query($dbc, $query); if(mysqli_num_rows($data)==1) { echo "You already posted this ad. Most likely caused by refreshing too many times."; } }

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