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  • What's the best way to select max over multiple fields in SQL?

    - by allyourcode
    The I kind of want to do is select max(f1, f2, f3). I know this doesn't work, but I think what I want should be pretty clear (see update 1). I was thinking of doing select max(concat(f1, '--', f2 ...)), but this has various disadvantages. In particular, doing concat will probably slow things down. What's the best way to get what I want? update 1: The answers I've gotten so far aren't what I'm after. max works over a set of records, but it compares them using only one value; I want max to consider several values, just like the way order by can consider several values. update 2: Suppose I have the following table: id class_name order_by1 order_by_2 1 a 0 0 2 a 0 1 3 b 1 0 4 b 0 9 I want a query that will group the records by class_name. Then, within each "class", select the record that would come first if you ordered by order_by1 ascending then order_by2 ascending. The result set would consist of records 2 and 3. In my magical query language, it would look something like this: select max(* order by order_by1 ASC, order_by2 ASC) from table group by class_name

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  • Iinsert FLV video in latex document

    - by Kami
    Hi, I'm trying to insert a flv video in a latex document. I've tried the following : \begin{figure}[h!] \centering \includegraphics[scale=1]{animation/animation1.flv} \caption{My animation} \label{Anim1} \end{figure} But it's not working at all ! Does anyone know how to do this ? I would avoid to convert the video because I don't know what kind of codec the reader would have.

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  • PDO Database Connections Problem

    - by Metropolis
    Hey Everyone, Over a year ago I created my own database classes which use PDO, and handle all preparing, executing, and closing connections. These classes have been working great up until now. There are two different database severs I am grabbing from, MySQL, and MS SQL Express. I am retrieving an employee id from the MySQL server and using it to get that employees information from the MS SQL server. There are about 11k records coming from the MySQL server and my program is only making it through 1200 before crashing with an error like the following. Connection failed (odbc:Driver=FreeTDS;Servername=MSSQLExpress;Database=SMDINC) Class (PDOException) SQLSTATE[08001] SQLDriverConnect: 0 [unixODBC][FreeTDS][SQL Server]Unable to connect to data source It seems like the program is not able to connect to the data source, but it is running the exact same query about 30 times before this and having no problem. Also, I have thoroughly checked all of the data coming into the query and it all looks fine. I believe the issue may be that there are to many connections being created, but I have tried to close all connections in many different places, and nothing seems to be fixing the problem. Any debugging help, or suggestions would be appreciated! Craig Metrolis

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  • SQLAlchemy: select over multiple tables

    - by ahojnnes
    Hi, I wanted to optimize my database query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( not_(link_table.c.id.in_( select( columns=[request_table.c.recipient], whereclause=request_table.c.donator==donator.id ).as_scalar() )), link_table.c.id!=donator.id, ), limit=20, ).execute().fetchall() and tried to merge those two selects in one query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( link_table.c.active==True, link_table.c.id!=donator.id, request_table.c.donator==donator.id, link_table.c.id!=request_table.c.recipient, ), limit=20, order_by=[link_table.c.rating.desc()] ).execute().fetchall() the database-schema looks like: link_table = Table('links', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('url', Unicode(250), index=True, unique=True), Column('registration_date', DateTime), Column('donations_in', Integer), Column('active', Boolean), ) request_table = Table('requests', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('recipient', Integer, ForeignKey('links.id')), Column('donator', Integer, ForeignKey('links.id')), Column('date', DateTime), ) There are several links (donator) in request_table pointing to one link in the link_table. I want to have links from link_table, which are not yet "requested". But this does not work. Is it actually possible, what I'm trying to do? If so, how would you do that? Thank you very much in advance!

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  • Access denied when trying to access my database.

    - by Sergio Tapia
    Here's my code: <html> <head> </head> <body> <?php $user = mysql_real_escape_string($_GET["u"]); $pass = mysql_real_escape_string($_GET["p"]); $query = "SELECT * FROM usario WHERE username = '$user' AND password = '$pass'"; mysql_connect(localhost, "root", ""); @mysql_select_db("multas") or die( "Unable to select database"); $result=mysql_query($query); if(mysql_numrows($result) > 0){ echo 'si'; } ?> </body> </html> And here's the error I get when I try to run it Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\useraccess.php on line 7 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: A link to the server could not be established in C:\xampp\htdocs\useraccess.php on line 7 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\useraccess.php on line 8 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: A link to the server could not be established in C:\xampp\htdocs\useraccess.php on line 8 Warning: mysql_numrows() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\useraccess.php on line 16

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  • Mysql concurrency: what happens if a locked table is accessed?

    - by PixelSapiens
    the question is rather simple but I couldn't find a precise answer: in a myisam db, what happens if a php file locks a table (with an atomic operation, say an INSERT) and another php file tries to access the same table (reading or writing)? Now, while it is obvious that the second session will not be able to access the table, what exactly happens? Does it return some kind of error? Does is wait in queue until it is able to access it? Thanks in advance!

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  • select for update problem in jdbc

    - by kartiku
    I'm having a problem with select for update in jdbc. The table i'm trying to update is the smalldb table, i'm having problems-- i'm using select for update which does a lock on the selected row the update statement is -- String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE name = ?"; the select statement is -- rs = stmt1.executeQuery("SELECT hIx FROM libra.smalldb for update"); rs0 = stmt2.executeQuery("SELECT name,aff FROM libra.smalldb"); the second statement is because i need those fields as well. Here is the complete code -- import java.sql.*; import java.util.ArrayList; import java.util.Collections; public class Jdbcexample1 { /** * @param args */ public static void main(String[] args) { Connection con = null; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); con = DriverManager.getConnection("jdbc:mysql:///test", "root", "*****"); //String url = "jdbc:msql://200.210.220.1:1114/Demo"; //Connection conn = DriverManager.getConnection(url,"",""); Statement stmt1 = con.createStatement(); Statement stmt2 = con.createStatement(); Statement stmt3 = con.createStatement(); Statement stmt4 = con.createStatement(); ResultSet rs0; ResultSet rs; ResultSet rs1; ResultSet rs2; String name; String hIx; int hIxInt; StringBuffer sb = new StringBuffer(); String affiliationSmall; ArrayList<String> affiliation = new ArrayList<String>(); ArrayList<Float> matchValues = new ArrayList<Float>(); ArrayList<Integer> hixValues = new ArrayList<Integer>(); ArrayList<Integer> idValues = new ArrayList<Integer>(); boolean moreFlag = false; String queryString; int tmpIdx; String name1; //get the hix at that index where the similarity is maximum int tmpHidx = 0; int tmpHix = 0; int id = 0; int count; int tmpidIdx = 0; //rs = stmt.executeQuery("SELECT id FROM libra.researchint WHERE id = 910887"); // Get name, affiliation , hIx from smalldb //rs = stmt1.executeQuery("SELECT name,aff,hIx FROM libra.smalldb"); // String cursorName = "OUR_CURSOR"; // stmt1.setCursorName(cursorName); //rs = stmt1.executeQuery("SELECT name,aff,hIx FROM libra.smalldb for update"); rs = stmt1.executeQuery("SELECT hIx FROM libra.smalldb for update"); rs0 = stmt2.executeQuery("SELECT name,aff FROM libra.smalldb"); while ( rs.next() && rs0.next() ) { //String lastName = rs.getString("id"); hIx = rs.getString("hIx"); hIxInt = Integer.parseInt(hIx); //if hIx if (hIxInt==-1) continue; //name = rs.getString("name"); name = rs0.getString("name"); name1 = new String(name); System.out.println(name); //affiliationSmall = rs.getString("aff"); affiliationSmall = rs0.getString("aff"); //name = "\"" +name+ "\""; // Get matching names from large faculty table //String queryString = "SELECT id,name,hIx FROM libra.faculty WHERE name = " +name; //name = does not work names are similar but not same (in faculty and // smalldb) String query = "SELECT id,name,hIx FROM libra.faculty WHERE name like ?"; //String query = "SELECT id,name,hIx FROM libra.faculty for update of hIx WHERE name like ?"; PreparedStatement prepStmt = con.prepareStatement(query); String[] nameArr = name.split(" "); StringBuffer tmpSb = new StringBuffer(); for(int idx = 0;idx<nameArr.length;idx++) { tmpSb.append(nameArr[idx] + "%"); } name = tmpSb.toString(); prepStmt.setString(1, name); rs1 = prepStmt.executeQuery(); //Try to get matching names from faculty big db //Execute the query on faculty table //rs1 = stmt2.executeQuery(queryString); if(rs1.isClosed()) continue; count = 0; matchValues.clear(); affiliation.clear(); while(rs1.next()) { //name = rs1.getString("name"); id = Integer.parseInt(rs1.getString("id")); //idValues.add(id); tmpHix = Integer.parseInt(rs1.getString("hIx")); queryString = "SELECT aff FROM libra.affiliation WHERE id = "+id; rs2 = stmt3.executeQuery(queryString); //affiliation = rs1.getString("aff"); sb.delete(0, sb.length()); while (rs2.next()) { //Concatenate it to the same string using a stringbuffer sb.append(rs2.getString("aff")); //affiliation.add(rs2.getString("aff")); } affiliation.add(sb.toString()); count++; // if(count1) // { // moreFlag = true; // //Call fuzzy match function, store the distance values and select the // //affiliation that has the minimum distance from affiliationSmall // // //problem is here, affiliation.get Index: 2, Size: 2 // // matchValues.add(fuzzyMatch(affiliationSmall,affiliation.get(count))); // hixValues.add(tmpHix); // idValues.add(id); // } }//end of while rs1 -> faculty rs1.close(); int idx = 0; if(count>1) { moreFlag = true; //Call fuzzy match function, store the distance values and select the //affiliation that has the minimum distance from affiliationSmall //problem is here, affiliation.get Index: 2, Size: 2 matchValues.add(fuzzyMatch(affiliationSmall,affiliation.get(idx))); hixValues.add(tmpHix); idValues.add(id); idx++; } if(moreFlag) { Object obj = Collections.max(matchValues); float maxVal = Float.parseFloat(obj.toString()); //int tmpIdx = matchValues.indexOf(new Float(maxVal)); //get the index at which similarity between affiliation strings is maximum, //as returned by fuzzyMatch //int tmpIdx = matchValues.indexOf(maxVal); tmpIdx = matchValues.indexOf(maxVal); //get the hix at that index where the similarity is maximum //int tmpHidx = hixValues.get(tmpIdx); tmpHidx = hixValues.get(tmpIdx); tmpidIdx = idValues.get(tmpIdx); //update the smalldb table String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE name = ?"; //String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE current of "+cursorName; //PreparedStatement prepStmt1 = con.prepareStatement("UPDATE libra.smalldb SET hIx = ? WHERE current of "+cursorName); PreparedStatement prepStmt1 = con.prepareStatement(updateQ); //PreparedStatement prepStmt1 = con.prepareStatement(updateQ); prepStmt1.setString(2, name1); prepStmt1.setString(1, Integer.toString(tmpHidx)); prepStmt1.executeUpdate(updateQ); //prepStmt1.execute(); //stmt4.executeUpdate(updateQ); }//end of if //For matching names get the affiliation based on id from affiliation table //con.close(); //System.out.println(lastName); System.out.println(name); }//end of while rs -> smalldb rs.close(); // String updateQ = "UPDATE libra.smalldb1 SET hIx = "+Integer.toString(tmpHidx)+ "WHERE id = "+Integer.toString(tmpidIdx); // stmt4.executeUpdate(updateQ); con.close(); } catch (Exception e) { System.err.println("Got an exception! "); System.err.println(e.getMessage()); e.printStackTrace(); } } public static float fuzzyMatch(String affiliationSmall, String affiliation) { //float distance = 0; String[] temp = null; temp = affiliationSmall.split(" "); int index; //int index1 = affiliation.indexOf(affiliationSmall); int matchCount = 0; for (int idx = 0;idx<temp.length; idx++) { index = affiliation.indexOf(temp[idx]); if (index!=-1) { matchCount++; } } float tmpFloat = matchCount/temp.length; //int[] aff1= new int[affiliation1.length()]; //int[] aff2 = new int[affiliation2.length()]; return tmpFloat; } } i think it is because of the second select statement (rs0) Here is the error- Got an exception! You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1 com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) at com.mysql.jdbc.Util.getInstance(Util.java:384) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3562) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3494) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1960) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2114) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2690) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1648) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1567) at Jdbcexample1.main(Jdbcexample1.java:184)

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  • Strange behavior with complex Q object filter queries in Django

    - by HWM-Rocker
    Hi I am trying to write a tagging system for Django, but today I encountered a strange behavior in filter or the Q object (django.db.models.Q). I wrote a function, that converts a search string into a Q object. The next step would be to filter the TaggedObject with these query. But unfortunately I get a strange behavior. when I search (id=20) = Q: (AND: ('tags__tag__id', 20)) and it returns 2 Taged Objects with the ID 1127 and 132 when I search (id=4) = Q: (AND: ('tags__tag__id', 4)) and it returns also 2 Objects, but this time 1180 and 1127 until here is everything fine, but when i make a little bit more complex query like (id=4) or (id=20) = Q: (OR: ('tags__tag__id', 4), ('tags__tag__id', 20)) then it returns 4(!) Objects 1180, 1127, 1127, 132 But the object with the ID 1127 is returned twice, but thats not the behaviour I want. Do I have to live with it, and uniqify that list or can I do something different. The representation of the Q object looks fine for me. But the worst is now, when I search for (id=20) and (id=4) = Q: (AND: ('tags__tag__id', 20), ('tags__tag__id', 4)) then it returns no object at all. But why? The representation should be ok and the object with the id 1127 is tagged by both. What am I missing? Here are also the relevant parts of the classes, that are involved: class TaggedObject(models.Model): """ class that represent a tagged object """ tags = generic.GenericRelation('ObjectTagBridge', blank=True, null=True) class ObjectTagBridge(models.Model): """ Help to connect a generic object to a Tag. """ # pylint: disable-msg=W0232,R0903 content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') tag = models.ForeignKey('Tag') class Tag(models.Model): ... Thanks for your help

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  • property names are different from original Object in the silverlight

    - by kwon
    Following is part of service layer which is provided by WCF service : [Serializable] public class WaitInfo { private string roomName; private string pName; private string tagNo; public string RoomName { get { return roomName; } set { this.roomName = value; } } public string PName { get { return pName; } set { this.pName = value; } } public string TagNo { get { return tagNo; } set { this.tagNo = value; } } } public class Service1 : IService1 { public List<WaitInfo> GetWaitingList() { MyDBDataContext db = new MyDBDataContext(); var query = from w in db.WAIT_INFOs select new WaitInfo { TagNo = w.PATIENT_INFO.TAG_NO, RoomName= w.ROOM_INFO.ROOM_NAME, PName= w.PATIENT_INFO.P_NAME }; List<WaitInfo> result = query.ToList(); return result; } And following is codebehind part of UI layer which is provided by Silverlight public MainPage() { InitializeComponent(); Service1Client s = new Service1Client(); s.GetWaitingListCompleted += new EventHandler<GetWaitingListByCompletedEventArgs>( s_GetWaitingListCompleted); s.GetWaitingListAsync(); } void s_GetWaitingListCompleted(object sender, RadControlsSilverlightApplication1.ServiceReference2.GetWaitingListByCompletedEventArgs e) { GridDataGrid.ItemsSource = e.Result; } And following is xaml code in Silverlight page <Grid x:Name="LayoutRoot"> <data:DataGrid x:Name="GridDataGrid"></data:DataGrid> </Grid> Is is very simple code, however what I am thinking weird is property name of object at "e.Result" in the code behind page. In the service layer, although properties' names are surely "RoomName, PName, TagNo", in the silverlight properties' names are "roomName, pName, tagNo" which are private variable name of the WaitingList Object. Did I something wrong? Thanks in advance.

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  • problem with date in sql CE

    - by Gold
    i have sqlCE DataBase, i have Tdate field (datetime) i notice that his format is: MM/DD/YYYY in my C# program i work with date in: DD/MM/YYYY format. how i can insert to my sqlCE data base my C# format ?

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  • default value support for Entity Framework object construction to avoid having to set this column pa

    - by Greg
    Hi, In entity framework is there a way to have a default value for a column such that Linq to Entity won't require this parameter when constructing a new object? For example I've marked on column in the EF designer with a default value (I typed in "All" as it was a string). But if I try to construct a new record and not specify this parameter I still get a FOREIGN KEY constraint exception. The INSERT statement conflicted with the FOREIGN KEY constraint "FK_FunctionalityTypeInterfaceRelationship"

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  • Best way to store and deliver files on a CMS

    - by Tio
    Hi all.. First of all, this isn't another question about storing images on DB vs file system. I'm already storing the images on the file system. I'm just struggling to find a better way to show them to all my users. I' currently using this system. I generate a random filename using md5(uniqueid()), the problem that I'm facing, is that the image is then presented with a link like this: <img src="/_Media/0027a0af636c57b75472b224d432c09c.jpg" /> As you can see this isn't the prettiest way to show a image ( or a file ), and the name doesn't say anything about the image. I've been working with a CMS system at work, that stores all uploaded files on a single table, to access that image it uses something like this: <img src="../getattachment/94173104-e03c-499b-b41c-b25ae05a8ee1/Menu-1/Escritorios.aspx?width=175&height=175" /> As you can see the path to the image, now has a meaning compared to the other one, the problem is that this put's a big strain in the DB, for example, in the last site I made, I have an area that has around 60 images, to show the 60 images, I would have to do at least 60 individual query's to the database, besides the other query's to retrieve the various content on the page. I think you understand my dilemma, has anyone gone trough this problem, that can give me some pointers on how to solve this? Thanks..

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  • Oracle Date Format Convert Hour-Minute to Interval and Disregard Year-Month-Day

    - by dlite922
    I need to compare an event's half-way midpoint between a start and stop time of day. Right now i'm converting the dates you see on the right, to HH:MM and the comparison works until midnight. the query says: WHERE half BETWEEN pStart and pStop. As you can see below, pStart and pStap have January 1st 2000 dates, this is because the year month day are not important to me... Valid Data: +-------+--------+-------+---------------------+---------------------+---------------------+ | half | pStart | pStop | half2 | pStart2 | pStop2 | +-------+--------+-------+---------------------+---------------------+---------------------+ | 19:00 | 19:00 | 23:00 | 2012-11-04 19:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 20:00 | 19:00 | 23:00 | 2012-11-04 20:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 21:00 | 19:00 | 23:00 | 2012-11-04 21:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 23:00 | 20:00 | 23:00 | 2012-11-05 23:00:00 | 2000-01-01 20:00:00 | 2000-01-01 23:00:00 | +-------+--------+-------+---------------------+---------------------+---------------------+ Now observe what happens when pStop is midnight or later... Valid Data that breaks it: +-------+--------+-------+---------------------+---------------------+---------------------+ | half | pStart | pStop | half2 | pStart2 | pStop2 | +-------+--------+-------+---------------------+---------------------+---------------------+ | 23:00 | 22:00 | 00:00 | 2012-11-04 23:00:00 | 2000-01-01 22:00:00 | 2000-01-01 00:00:00 | | 23:30 | 23:00 | 02:00 | 2012-11-05 23:30:00 | 2000-01-01 23:00:00 | 2000-01-01 02:00:00 | +-------+--------+-------+---------------------+---------------------+---------------------+ Thus my where clause translates to: WHERE 19:00 BETWEEN 22:00 AND 00:00 ...which returns false and I miss those two correct rows above. Question: Is there a way to show those dates as integer interval so that saying half BETWEEN pStart and pStop are correct? I thought about adding 24 when pStop is less than pStart to make 00:00 into 24:00 but don't know an easy way to do that without long string concatenations and number conversions. This would solve the problem because pStart pStop difference will never be longer than 6 hours. Note: (The Query is much more complex. It has other irrelevant date calculations, but the result are show above. DATE_FORMAT(%H:%i) is applied to the first three columns and no formatting to the last three) Thanks for your help:

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  • Regular expression for finding non-breaking string names in code and then breaking them up for SQL q

    - by Rob Segal
    I am trying to devlop a regex for finding camel case strings in several code files I am working with so I can break them up into separate words for use in a SQL query. I have strings of the form... EmailAddress FirstName MyNameIs And I want them like this... Email Address First Name My Name Is An example SQL query which I currently have is... select FirstName, MyNameIs from MyTables I need the queries in the form... select FirstName as 'First Name', MyNameIs as 'My Name Is' from MyTables Any time a new capital letter appears that should be a new grouping which I can pick out of the matched string. I currently have the following regex... ([A-Z][a-z]+)+ Which does match the cases I have shown above but when I want to perform a replace I need to define groups. Currently I have tried... (([A-Z])([a-z]+))+ Which sort of works. It will pick out "Address" as the first grouping from "EmailAddress" as opposed to "Email" which is what I was expecting. No doubt there is something I'm misunderstanding here so any help is greatly appreciated.

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  • filter some data(row) in zend view

    - by Behrang
    I have 1.Table:user(userId,userName,userGroup) 2.Model:userModel 3.usercontroller there i a simple code: Controller: class UserController extends Zend_Controller_Action { public function getuser() { $userModel = new userModel(); $this-view-usergroup = $userModel; } } Model: class Model_UserGroupModel extends Zend_Db_Table_Abstract { public function getuser( { $select = $this-select(); return $this-fetchAll($select); } } view: please tell me what code I must insert in view to only have user with specific row like user with group teacher also i use partialoop???

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  • Row selection based on subtable data in MySQL

    - by Felthragar
    I've been struggling with this selection for a while now, I've been searching around StackOverflow and tried a bunch of stuff but nothing that helps me with my particular issue. Maybe I'm just missing something obvious. I have two tables: Measurements, MeasurementFlags "Measurements" contain measurements from a device, and each measurement can have properties/attributes attached to them (commonly known as "flags") to signify that the measurement in question is special in some way or another (for instance, one flag may signify a test or calibration measurement). Note: One record per flag! Right, so a record from the "Measurements" table can theoreticly have an unlimited amount of MeasurementFlags attached to it, or it can have none. Now, I need to select records from "Measurements", that have an attached "MeasurementFlag" valued "X", but it must also NOT have a flag valued "Y" attached to it. We're talking about a fairly large database with hundreds of millions of rows, which is why I'm trying to keep all of this logic within one query. Splitting it up would create too many queries, however if it's not possible to do in one query I guess I don't have a choise. Thanks in advance.

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  • jqGrid : "All in One" approach width jqGridEdit Class > how to set a composite primary key ?

    - by Qualliarys
    Hello, How to set a composite primary key for a "All in One" approach (grid defined in JS file, and data using jqGridEdit Class in php file) ? Please, for me a composite primary key of a table T, is a elementary primary key that is defined with some fields belong to this table T ! Here is my test, but i get no data and cannot use the CRUD operations : In my JS file i have this lines code: ... colModel":[ {"name":"index","index":"index","label":"index"}, // <= THAT'S JUST THE INDEX OF MY TABLE {"name":"user","index":"user","label":"user","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"pwd","index":"pwd","label":"pwd","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"state","index":"state","label":"state","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY ... <= AND SO ON "url":"mygrid_crud.php", "datatype":"json", "jsonReader":{repeatitems:false}, "editurl": "mygrid_crud.php", "prmNames":{"id":"index"} // <= WHAT I NEED TO WRITE HERE ??? ... In my php file (mygrid_crud.php) : ... $grid = new jqGridEdit($conn); $query = "SELECT * FROM mytable WHERE user='$user' and pwd='$pwd' and state='$state'..."; // <= SELECT * it's ok or i need to specify all fields i need ? $grid->SelectCommand = $query; $grid->dataType = "json"; $grid->table = 'mytable'; $grid->setPrimaryKeyId('index'); // <= WHAT I NEED TO WRITE HERE ??? ... $grid->editGrid(); Please, say me what is wrong, and how to do to set a composite primary key in this approach !? Thank you so much for tour responses.

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  • SQL Distinct keyword in assignment statement

    - by Brandi
    I have a query that works: DECLARE @ProductID int SET @ProductID = '1234' SELECT DISTINCT TOP 12 a.ProductID FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE b.ProductID = @ProductID) AND a.ProductID != @ProductID It returns a list of 12 product numbers, all unique. I need to store these results in a variable, comma separated, because that's what 3rd party stored procedure needs. So I have this: DECLARE @ProductID int DECLARE @relatedprods varchar(8000) SET @ProductID = '1234' SET @relatedprods = '' SELECT TOP 12 @relatedprods = @relatedprods + CONVERT(VARCHAR(20), a.ProductID) + ', ' FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE B.ProductID = @ProductID) AND a.ProductID != @ProductID SELECT @relatedprods Now, none of these are distinct, but it is returning 12 rows. Now I add the 'distinct' back in, like in the first query: DECLARE @ProductID int DECLARE @relatedprods varchar(8000) SET @ProductID = '1234' SET @relatedprods = '' SELECT DISTINCT TOP 12 @relatedprods = @relatedprods + CONVERT(VARCHAR(20), a.ProductID) + ', ' FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE B.ProductID = @ProductID) AND a.ProductID != @ProductID SELECT @relatedprods Only one product is returned in the comma separated list! Does 'distinct' not work in assignment statements? What did I do wrong? Or is there a way to get around this? Thanks in advance!

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  • Rails ActiveRecord Transaction does not finish

    - by PanosJee
    Hi everyone, I have a Transaction for a batch insert/update block and all of sudden it stopped working. The are no errors or exception risen and it seems like Rails stops just before the end of the Transaction blog so the methods does not return. I restarted both MySQL and the system but still.

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  • Does complex JOINs causes high coupling and maintenance problems ?

    - by ashkan.kh.nazary
    Our project has ~40 tables with complex relations.A colleague believes in using long join queries which enforces me to learn about tables outside of my module but I think I should not concern about tables not directly related to my module and use data access functions (written by those responsible for other modules) when I need data from them. Let me clarify: I am responsible for the ContactVendor module which enables the customers to contact the vendor and start a conversation about some specific product. Products module has it's own complex tables and relations with functions that encapsulate details (for example i18n, activation, product availability etc ...). Now I need to show the product title of some product related to some conversation between the vendor and customers. I may either write a long query that retrieves the product info along with conversation stuff in one shot (which enforces me to learn about Product tables) OR I may pass the relevant product_id to the get_product_info(int) function. First approach is obviously demanding and introduces many bad practices and things I normally consider fault in programming. The problem with the second approach seems to be the countless mini queries these access functions cause and performance loss is a concern when a loop tries to fetch product titles for 100 products using functions that each perform a separate query. So I'm stuck between "don't code to the implementation, code to interface" and performance. What is the right way of doing things ? UPDATE: I'm specially concerned about possible future modifications to those tables outside of my module. What if the Products module decided to change the way they are doing things? or for some reason modify the schema? It means some other modules would break or malfunction until the change is integrated to them. The usual ripple effect problem.

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