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  • rails semi-complex STI with ancestry data model planning the routes and controllers

    - by ere
    I'm trying to figure out the best way to manage my controller(s) and models for a particular use case. I'm building a review system where a User may build a review of several distinct types with a Polymorphic Reviewable. Country (has_many reviews & cities) Subdivision/State (optional, sometimes it doesnt exist, also reviewable, has_many cities) City (has places & review) Burrow (optional, also reviewable ex: Brooklyn) Neighborhood (optional & reviewable, ex: williamsburg) Place (belongs to city) I'm also wondering about adding more complexity. I also want to include subdivisions occasionally... ie for the US, I might add Texas or for Germany, Baveria and have it be reviewable as well but not every country has regions and even those that do might never be reviewed. So it's not at all strict. I would like it to as simple and flexible as possible. It'd kinda be nice if the user could just land on one form and select either a city or a country, and then drill down using data from say Foursquare to find a particular place in a city and make a review. I'm really not sure which route I should take? For example, what happens if I have a Country, and a City... and then I decide to add a Burrow? Could I give places tags (ie Williamsburg, Brooklyn) belong_to NY City and the tags belong to NY? Tags are more flexible and optionally explain what areas they might be in, the tags belong to a city, but also have places and be reviewable? So I'm looking for suggestions for anyone who's done something related. Using Rails 3.2, and mongoid.

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  • Why aren't my objects sorting with sortedArrayUsingDescriptors?

    - by clozach
    I expected the code below to return the objects in imageSet as a sorted array. Instead, there's no difference in the ordering before and after. NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"imageID" ascending:YES]; NSSet *imageSet = collection.images; for (CBImage *image in imageSet) { NSLog(@"imageID in Set: %@",image.imageID); } NSArray *imageArray = [[imageSet allObjects] sortedArrayUsingDescriptors:(descriptor, nil)]; [descriptor release]; for (CBImage *image in imageArray) { NSLog(@"imageID in Array: %@",image.imageID); } Fwiw, CBImage is defined in my core data model. I don't know why sorting on managed objects would work any differently than on "regular" objects, but maybe it matters. As proof that @"imageID" should work as the key for the descriptor, here's what the two log loops above output for one of the sets I'm iterating through: 2010-05-05 00:49:52.876 Cover Browser[38678:207] imageID in Array: 360339 2010-05-05 00:49:52.876 Cover Browser[38678:207] imageID in Array: 360337 2010-05-05 00:49:52.877 Cover Browser[38678:207] imageID in Array: 360338 2010-05-05 00:49:52.878 Cover Browser[38678:207] imageID in Array: 360336 2010-05-05 00:49:52.879 Cover Browser[38678:207] imageID in Array: 360335 ... For extra credit, I'd love to get a general solution to troubleshooting NSSortDescriptor troubles (esp. if it also applies to troubleshooting NSPredicate). The functionality of these things seems totally opaque to me and consequently debugging takes forever.

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  • How to parse XML file to get specific data effectively

    - by Carlos_Liu
    I have an XML file looks like this: <?xml version="1.0" encoding="utf-8" ?> <PathMasks> <Mask desc="Masks_X1"> <config id="01" mask="88" /> <config id="03" mask="80" /> <config id="51" mask="85" /> </Mask> <Mask desc="Masks_X2"> <config id="70" mask="1" /> <config id="73" mask="6" /> </Mask> <Types> <path id="01" desc="TC->PP1" /> <path id="02" desc="TC->PP2" /> <path id="03" desc="TC->PPn" /> </Types> </PathMasks> How to parse the file and get all the data of Mask_X1 as following: id value ===== 01, 88 03, 80 51, 85

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  • External data in TileList Flex

    - by Adam
    I'm working for the first time with a TileList and an itemRenderer and I'm having a bit of trouble getting the information from my array collection to display and looking for some advice. Here's what I've got private function loadData():void{ var stmt:SQLStatement = new SQLStatement(); stmt.sqlConnection = sqlConn; stmt.text = "SELECT * FROM tbl_user ORDER BY user_id ASC"; stmt.execute(); var result:SQLResult = stmt.getResult(); acData = new ArrayCollection(result.data); } <mx:TileList id="userlist" labelField="user_id" dataProvider="{acData}" width="600" height="200" paddingTop="25" left="117.15" y="327.25"> <!--itemClick="showMessage(event)"--> <mx:itemRenderer> <mx:Component> <mx:VBox width="125" height="125" paddingRight="5" paddingLeft="5" horizontalAlign="center"> <mx:Label id="username" text="{}"/> <mx:Label id="userjob" text="{}"/> </mx:VBox> </mx:Component> </mx:itemRenderer> </mx:TileList> So I'm just not sure how I go about pulling the information from the array and putting it into labels like username, userjob, userbio ect, Inside the TitleList and itemRenderer.

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  • Generating MySQL UPDATE statements containing BLOB image data

    - by Bob
    I'm trying to write an SQL statement that will generate an SQL script that will update a BLOB field with an IMAGE being selected from the database. This is what I have: select concat( 'UPDATE `IMAGE` SET THUMBNAIL = ', QUOTE( THUMBNAIL ), ' WHERE ID = ', ID, ';' ) as UPDATE_STATEMENT from IMAGE; In the above, THUMBNAIL is a BLOB field containing raw image data. When I run the resulting script I get the following error: ERROR at line 2: Unknown command '\\'. I first tried this without the QUOTE() function, like so: select concat( 'UPDATE `IMAGE` SET THUMBNAIL = \'', THUMBNAIL, '\' WHERE ID = ', ID, ';' ) as UPDATE_STATEMENT from IMAGE; Running the resulting script produces this error: ERROR at line 2: Unknown command '\0'. What is the proper function to apply to this BLOB field in the select, so the UPDATE statements will work? If context is required, I'm looking to migrate thumbnails generated on one server to another server for certain image IDs only. I would use mysqldump, but I don't want to clobber the entire table. Any help is greatly appreciated!

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  • iPhone OS: Why is my managedModelObject not complying with Key Value Coding?

    - by nickthedude
    Ok so I'm trying to build this stat tracker for my app and I have built a data model object called statTracker that keeps track of all the stuff I want it to. I can set and retrieve values using the selectors, but if I try and use KVC (ie setValue: forKey: ) everything goes bad and says my StatTracker class is not KVC compliant: valueForUndefinedKey:]: the entity StatTracker is not key value coding-compliant for the key "timesLauched".' 2010-05-18 15:55:08.573 here's the code that is triggering it: NSArray *statTrackerArray = [[NSArray alloc] init]; statTrackerArray = [[CoreDataSingleton sharedCoreDataSingleton] getStatTracker]; NSNumber *number1 = [[NSNumber alloc] init]; number1 = [NSNumber numberWithInt:(1 + [[(StatTracker *)[statTrackerArray objectAtIndex:0] valueForKey:@"timesLauched"] intValue])]; [(StatTracker *)[statTrackerArray objectAtIndex:0] setValue:number1 forKey:@"timesLaunched" ]; NSError *error; if (![[[CoreDataSingleton sharedCoreDataSingleton] managedObjectContext] save:&error]) { NSLog(@"error writing to db"); } Not sure if this is enough code for you folks let me know what you need if you do need more. This would be so sweet if I could use KVC because I could then abstract all this stat tracking stuff into a single method call with a string argument for the value in question. At least that is what I hope to accomplish here. I'm actually now understanding the power of KVC but now I'm just trying to figure out how to make it work. Thanks! Nick

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  • Data synchronization using XMPP

    - by Jason
    Hi: I'm looking for some insight/advice on synchronizing data over XMPP. I've never developed anything for XMPP before so excuse me if some of my questions seem ridiculous. Basically, what I have is a decentralized social network. Each person has it's own Web site (or server) with a unique URI (one domain could host many servers). Each of these servers can have many clients. E.g., a desktop application, mobile application, etc. What I would like to accomplish is near real-time synchronization/communication between client and server, e.g., I update something on my desktop application, I see it change on my Web site. My server and client code is Python. So, I would like to make use of SleekXMPP if possible (it's license seems to have changed to MIT). I was thinking, and here is where I need advice, that each server would register an account at a dedicated XMPP server, e.g., [email protected]. and then I could use different resources for clients [email protected]/client1, [email protected]/client2, etc. If anyone can register any username, then maybe I also need some intermediate service (since it's decentralized, i'm not sure how to control registrations). Another option, I guess, is that each server runs it's own xmpp server. Assuming, that was all worked out, if I want to broadcast messages to all my resources (except the sending one), how do I do that? Do I have to subscribe to myself? This also seems like a good candidate for publish-subscribe, let me know if you think that could work and what the design/flow of that process would be. thanks :)

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  • Codeigniter: db data in controller

    - by Kevin Brown
    I'm confused about what to do... I'm working on a user's page where they can view certain things only if their supervisor has given them "money" or "credits". I need a simple way to get the person that is their supervisor by doing something like: $data['employer'] = $this->home_model->getEmployees(array('user_id'=>$manager_id)); Basically, get the user information about a person who's user_id matches the manager_id of the currently logged in member. I don't know how to set the variable $manager_id. Additional Information: The current user has an id, and a manager_id. I need the id of the manager. So, I need to grab the manager_id of the logged-in user and find the manager who's user_id is that of the manager_id. What's the process to do this? I can get each individually, but I don't know how to use one to get the other... I know it is confusing, but I'm confused! Thanks for the help!

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  • Rails nested models and data separation by scope

    - by jobrahms
    I have Teacher, Student, and Parent models that all belong to User. This is so that a Teacher can create Students and Parents that can or cannot log into the app depending on the teacher's preference. Student and Parent both accept nested attributes for User so a Student and User object can be created in the same form. All four models also belong to Studio so I can do data separation by scope. The current studio is set in application_controller.rb by looking up the current subdomain. In my students controller (all of my controllers, actually) I'm using @studio.students.new instead of Student.new, etc, to scope the new student to the correct studio, and therefore the correct subdomain. However, the nested User does not pick up the studio from its parent - it gets set to nil. I was thinking that I could do something like params[:student][:user_attributes][:studio_id] = @student.studio.id in the controller, but that would require doing attr_accessible :studio_id in User, which would be bad. How can I make sure that the nested User picks up the same scope that the Student model gets when it's created? student.rb class Student < ActiveRecord::Base belongs_to :studio belongs_to :user, :dependent => :destroy attr_accessible :user_attributes accepts_nested_attributes_for :user, :reject_if => :all_blank end students_controller.rb def create @student = @studio.students.new @student.attributes = params[:student] if @student.save redirect_to @student, :notice => "Successfully created student." else render :action => 'new' end end user.rb class User < ActiveRecord::Base belongs_to :studio accepts_nested_attributes_for :studio attr_accessible :email, :password, :password_confirmation, :remember_me, :studio_attributes devise :invitable, :database_authenticatable, :recoverable, :rememberable, :trackable end

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  • Problem with WHERE columnName = Data in MySQL query in C#

    - by Ryan Sullivan
    I have a C# webservice on a Windows Server that I am interfacing with on a linux server with PHP. The PHP grabs information from the database and then the page offers a "more information" button which then calls the webservice and passes in the name field of the record as a parameter. So i am using a WHERE statement in my query so I only pull the extra fields for that record. I am getting the error: System.Data.SqlClient.SqlException:Invalid column name '42' Where 42 is the value from the name field from the database. my query is string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\""; I do not know if it is a problem with my query or something is wrong with the database, but here is the rest of my code for reference. NOTE: this all works perfectly when I grab all of the records, but I only want to grab the record that I ask my webservice for. public class ktvService : System.Web.Services.WebService { [WebMethod] public string moreInfo(string show) { string connectionStr = "MyConnectionString"; string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\""; SqlConnection conn = new SqlConnection(connectionStr); SqlDataAdapter da = new SqlDataAdapter(selectStr, conn); DataSet ds = new DataSet(); da.Fill(ds, "tableName"); DataTable dt = ds.Tables["tableName"]; DataRow theShow = dt.Rows[0]; string response = "Name: " + theShow["name"].ToString() + "Cast: " + theShow["castNotes"].ToString() + " Trivia: " + theShow["triviaNotes"].ToString(); return response; } }

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  • MVC 2 - Name Attributes on HTML Input Field when using Parent/Child Entities

    - by Click Ahead
    Hi All, I'm pretty new to MVC 2 using the Entity Framework. I have two tables Company {ID int identity PK,Name nvarchar} and User {ID int identity PK,UserName nvarchar,CompanyID int FK}. A Foreign Key exists between User and Company. I generated my ADO.NET Entity Data Model, a Controller and a view to insert a record. My HTML form has the fields Company and UserName and the idea is when I click save a Company and User is inserted into the database. Sounds straight forward right! My question is as follows: I created a strongly-typed view derived from my 'User' entity. I'm using the the html helper Html.TextBoxFor(model = model.Organisation.Name) but the html name attribute for this input field is 'Organisation.Name'. My problem with this is that the dot throws up all sorts of issues in JQuery, which sees this as a property. If I want to change the name I read that I can use DataAnnotations but because I used the Entity Designer this involves using Buddy Classes. Seems like a bit of overkill just to change the html name attribute on this input field. Am I approaching this the right way or am I missing something here? Thanks for the help !

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  • Append data to same text file using java

    - by Manu
    SimpleDateFormat formatter = new SimpleDateFormat("ddMMyyyy_HHmmSS"); String strCurrDate = formatter.format(new java.util.Date()); String strfileNm = "Customer_" + strCurrDate + ".txt"; String strFileGenLoc = strFileLocation + "/" + strfileNm; String Query1="select '0'||to_char(sysdate,'YYYYMMDD')||'123456789' class_code from dual"; String Query2="select '0'||to_char(sysdate,'YYYYMMDD')||'123456789' class_code from dual"; try { Statement stmt = null; ResultSet rs = null; Statement stmt1 = null; ResultSet rs1 = null; stmt = conn.createStatement(); stmt1 = conn.createStatement(); rs = stmt.executeQuery(Query1); rs1 = stmt1.executeQuery(Query2); File f = new File(strFileGenLoc); OutputStream os = (OutputStream)new FileOutputStream(f,true); String encoding = "UTF8"; OutputStreamWriter osw = new OutputStreamWriter(os, encoding); BufferedWriter bw = new BufferedWriter(osw); while (rs.next() ) { bw.write(rs.getString(1)==null? "":rs.getString(1)); bw.write(" "); } bw.flush(); bw.close(); } catch (Exception e) { System.out.println( "Exception occured while getting resultset by the query"); e.printStackTrace(); } finally { try { if (conn != null) { System.out.println("Closing the connection" + conn); conn.close(); } } catch (SQLException e) { System.out.println( "Exception occured while closing the connection"); e.printStackTrace(); } } return objArrayListValue; } The above code is working fine. it writes the content of "rs" resultset data in text file Now what i want is ,i need to append the the content in "rs2" resultset to the "same text file"(ie . i need to append "rs2" content with "rs" content in the same text file)..

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  • Displaying Plist data into UItableview

    - by Christien
    I have a plist with Dictionary and numbers of strings per dictionary.show into the url below.and this list of items is in thousands in the plist. I need to display these plist data into the UItableview . How to do this? My Code: - (void)viewWillAppear:(BOOL)animated { // get paths from root direcory NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [documentPaths objectAtIndex:0]; NSString *documentPlistPath = [documentsDirectory stringByAppendingPathComponent:@"p.plist"]; NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:documentPlistPath]; valueArray = [dict objectForKey:@"title"]; self.mySections=[valueArray copy]; NSLog(@"value array %@",self.mySections); } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return [self.mySections count]; } -(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { NSString *key = [[self.mySections objectAtIndex:section]objectForKey:@"pass"]; return [NSString stringWithFormat:@"%@", key]; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 5; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier]; } // Configure the cell... NSUInteger section = [indexPath section]; NSUInteger row = [indexPath row]; cell.textLabel.text = [[self.mySections objectAtIndex:row] objectForKey:@"title"]; cell.detailTextLabel.text=[[self.mySections objectAtIndex:section] objectForKey:[allKeys objectAtIndex:1]]; return cell; } Error is 2012-12-17 16:21:07.372 Project[2076:11603] * Terminating app due to uncaught exception 'NSRangeException', reason: '-[__NSCFArray objectAtIndex:]: index (4) beyond bounds (4)' * First throw call stack: (0x1703052 0x1523d0a 0x16aba78 0x16ab9e9 0x16fcc60 0x1d03a 0x391e0f 0x392589 0x37ddfd 0x38c851 0x337301 0x1704e72 0x277592d 0x277f827 0x2705fa7 0x2707ea6 0x2707580 0x16d79ce 0x166e670 0x163a4f6 0x1639db4 0x1639ccb 0x1505879 0x150593e 0x2f8a9b 0x2158 0x20b5) terminate called throwing an exceptionkill

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  • smartGWT: retrieve data from server to populate a listGrid

    - by Gabriele
    I'm searching a way to populate a ListGrid with an XML response from a server. This is an example of my server response: <?xml version="1.0" encoding="UTF-8"?> <tbody id="tbody"> <tr> <word>The</word> <frequence>12</frequence> </tr> <tr> <word>best</word> <frequence>3</frequence> </tr> ... And this is how I can populate the ListGrid using a file (item.xml) where I have saved the xml result: public class Frequenze extends DataSource { private static Frequenze instance = null; public static Frequenze getInstance() { if (instance == null) { instance = new Frequenze("frequence"); } return instance; } public Frequenze(String id) { setID(id); setRecordXPath("//tr"); DataSourceTextField wordField = new DataSourceTextField("word", "Word"); wordField.setRequired(true); DataSourceIntegerField frequenceField = new DataSourceIntegerField("frequence", "Frequence"); frequenceField.setRequired(true); setFields(wordField, frequenceField); setDataURL("ds/item.xml"); setClientOnly(true); } } Now I want not to use the file, but I'm searching a way to retrieve the data directly from the server. Anyone know how I get this?

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  • Handle row deletion in UITableViewController

    - by Kamchatka
    Hello, I hava a UINavigationController. The first level is a UITableViewController, the second level just shows details on one of the items of the table view. In this detail view, I can delete the item. It deletes the underlying managed object. When I pop back to the view, I have a crash. I understand why, it's because I didn't update the cached array that contains the data. I looked at several tutorials and I don't exactly understand how am I supposed to handle deletion. Maybe I don't understand exactly where I should fetch the objects in the model. Should I do a query for every cellForRowAtIndexPath and take the item in the result at position indexPath.row? It doesn't look efficient. Should I check for changes somewhere and recache the whole query in an array. I would think CoreData would provide something more natural but I couldn't find it so far. Thanks in advance.

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  • Is there a standard syntax for encoding structure objects as HTTP GET request parameters?

    - by lexicore
    Imagine we need to pass a a number structured objects to the web application - for instance, locale, layout settings and a definition of some query. This can be easily done with JSON or XML similar to the following fragment: <Locale>en</Locale> <Layout> <Block id="header">hide</Block> <Block id="footer">hide</Block> <Block id="navigation">minimize</Block> </Layout> <Query> <What>water</What> <When> <Start>2010-01-01</Start> </When> </Query> However, passing such structures with HTTP implies (roughly speaking) HTTP POST. Now assume we're limited to HTTP GET. Is there some kind of a standard solution for encoding structured data in HTTP GET request parameters? I can easily imagine something like: Locale=en& Layout.Block.header=hide& Layout.Block.footer=hide& Layout.Block.navigation=minimize& Query.What=water& Query.When.Start=2010-01-01 But what I'm looking for is a "standard" syntax, if there's any. ps. I'm surely aware of the problem with URL length. Please assume that it's not a problem in this case.

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  • How to manipulate *huge* amounts of data

    - by Alejandro
    Hi there! I'm having the following problem. I need to store huge amounts of information (~32 GB) and be able to manipulate it as fast as possible. I'm wondering what's the best way to do it (combinations of programming language + OS + whatever you think its important). The structure of the information I'm using is a 4D array (NxNxNxN) of double-precission floats (8 bytes). Right now my solution is to slice the 4D array into 2D arrays and store them in separate files in the HDD of my computer. This is really slow and the manipulation of the data is unbearable, so this is no solution at all! I'm thinking on moving into a Supercomputing facility in my country and store all the information in the RAM, but I'm not sure how to implement an application to take advantage of it (I'm not a professional programmer, so any book/reference will help me a lot). An alternative solution I'm thinking on is to buy a dedicated server with lots of RAM, but I don't know for sure if that will solve the problem. So right now my ignorance doesn't let me choose the best way to proceed. What would you do if you were in this situation? I'm open to any idea. Thanks in advance!

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  • Binary Search Tree for specific intent

    - by Luís Guilherme
    We all know there are plenty of self-balancing binary search trees (BST), being the most famous the Red-Black and the AVL. It might be useful to take a look at AA-trees and scapegoat trees too. I want to do deletions insertions and searches, like any other BST. However, it will be common to delete all values in a given range, or deleting whole subtrees. So: I want to insert, search, remove values in O(log n) (balanced tree). I would like to delete a subtree, keeping the whole tree balanced, in O(log n) (worst-case or amortized) It might be useful to delete several values in a row, before balancing the tree I will most often insert 2 values at once, however this is not a rule (just a tip in case there is a tree data structure that takes this into account) Is there a variant of AVL or RB that helps me on this? Scapegoat-trees look more like this, but would also need some changes, anyone who has got experience on them can share some thougts? More precisely, which balancing procedure and/or removal procedure would help me keep this actions time-efficient?

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  • Searching a column containing CSV data in a MySQL table for existence of input values

    - by Adarsh R
    Hi, I have a table say, ITEM, in MySQL that stores data as follows: ID FEATURES -------------------- 1 AB,CD,EF,XY 2 PQ,AC,A3,B3 3 AB,CDE 4 AB1,BC3 -------------------- As an input, I will get a CSV string, something like "AB,PQ". I want to get the records that contain AB or PQ. I realized that we've to write a MySQL function to achieve this. So, if we have this magical function MATCH_ANY defined in MySQL that does this, I would then simply execute an SQL as follows: select * from ITEM where MATCH_ANY(FEAURES, "AB,PQ") = 0 The above query would return the records 1, 2 and 3. But I'm running into all sorts of problems while implementing this function as I realized that MySQL doesn't support arrays and there's no simple way to split strings based on a delimiter. Remodeling the table is the last option for me as it involves lot of issues. I might also want to execute queries containing multiple MATCH_ANY functions such as: select * from ITEM where MATCH_ANY(FEATURES, "AB,PQ") = 0 and MATCH_ANY(FEATURES, "CDE") In the above case, we would get an intersection of records (1, 2, 3) and (3) which would be just 3. Any help is deeply appreciated. Thanks

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  • Good practice to create extension methods that apply to System.Object?

    - by Christian
    Hello, I'm wondering whether I should create extension methods that apply on the object level or whether they should be located at a lower point in the class hierarchy. What I mean is something along the lines of: public static string SafeToString(this Object o) { if (o == null || o is System.DBNull) return ""; else { if (o is string) return (string)o; else return ""; } } public static int SafeToInt(this Object o) { if (o == null || o is System.DBNull) return 0; else { if (o.IsNumeric()) return Convert.ToInt32(o); else return 0; } } //same for double.. etc I wrote those methods since I have to deal a lot with database data (From the OleDbDataReader) that can be null (shouldn't, though) since the underlying database is unfortunately very liberal with columns that may be null. And to make my life a little easier, I came up with those extension methods. What I'd like to know is whether this is good style, acceptable style or bad style. I kinda have my worries about it since it kinda "pollutes" the Object-class. Thank you in advance & Best Regards :) Christian P.S. I didn't tag it as "subjective" intentionally.

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  • Database schemas WAY out of sync - need to get up to date without losing data

    - by Zind
    The problem: we have one application that has a portion which is used by a very small subset of the total users, and that part of the application is running off of a separate database as well. In a perfect world, the schemas of the two databases would be synced up, but such is not the case. Some migrations have been run on the smaller database, most haven't; and furthermore, there is nothing such as revision number to be able to easily identify which have and which haven't. We would like to solve this quandary for future projects. During a discussion we've come up with the following possible plan of action, and I am wondering if anyone knows of any project which has already solved this problem: What we would like to do is create an empty database from the schema of the large fully-migrated database, and then move all of the data from the smaller non-migrated database into that empty one. If it makes things easier, it can probably be assumed for the sake of this problem specifically that no migrations have ever removed anything, only added. Else, if there are other known solutions, I'd like to hear them as well.

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  • how to design a schema where the columns of a table are not fixed

    - by hIpPy
    I am trying to design a schema where the columns of a table are not fixed. Ex: I have an Employee table where the columns of the table are not fixed and vary (attributes of Employee are not fixed and vary). Nullable columns in the Employee table itself i.e. no normalization Instead of adding nullable columns, separate those columns out in their individual tables ex: if Address is a column to be added then create table Address[EmployeeId, AddressValue]. Create tables ExtensionColumnName [EmployeeId, ColumnName] and ExtensionColumnValue [EmployeeId, ColumnValue]. ExtensionColumnName would have ColumnName as "Address" and ExtensionColumnValue would have ColumnValue as address value. Employee table EmployeeId Name ExtensionColumnName table ColumnNameId EmployeeId ColumnName ExtensionColumnValue table EmployeeId ColumnNameId ColumnValue There is a drawback is the first two ways as the schema changes with every new attribute. Note that adding a new attribute is frequent. I am not sure if this is the good or bad design. If someone had a similar decision to make, please give an insight on things like foreign keys / data integrity, indexing, performance, reporting etc.

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  • Machine leaning algorithm for data classification.

    - by twk
    Hi all, I'm looking for some guidance about which techniques/algorithms I should research to solve the following problem. I've currently got an algorithm that clusters similar-sounding mp3s using acoustic fingerprinting. In each cluster, I have all the different metadata (song/artist/album) for each file. For that cluster, I'd like to pick the "best" song/artist/album metadata that matches an existing row in my database, or if there is no best match, decide to insert a new row. For a cluster, there is generally some correct metadata, but individual files have many types of problems: Artist/songs are completely misnamed, or just slightly mispelled the artist/song/album is missing, but the rest of the information is there the song is actually a live recording, but only some of the files in the cluster are labeled as such. there may be very little metadata, in some cases just the file name, which might be artist - song.mp3, or artist - album - song.mp3, or another variation A simple voting algorithm works fairly well, but I'd like to have something I can train on a large set of data that might pick up more nuances than what I've got right now. Any links to papers or similar projects would be greatly appreciated. Thanks!

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  • How to check if something is stored in CoreData

    - by Terrel Gibson
    Hi I want to be able to tore some information in core data and but i am unsure of how to check if the file was saved properly. I tried using NSLog but it returns null when its called. I have a dictionary which has a uniqueID and a title which I want to save. I pass this in along with the context of the database. I then sort the database to check if it has any duplicates or not, if not then I add the file. +(VacationPhoto*) photoWithFlickrInfo: (NSDictionary*) flickrInfo inManagedObjectContext: (NSManagedObjectContext*) context{ //returns the dictionary NSLog(@"Photo To Store =%@", flickrInfo); VacationPhoto * photo = nil; NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"VacationPhoto"]; request.predicate = [NSPredicate predicateWithFormat:@"uniqueID = %@", [flickrInfo objectForKey:FLICKR_PHOTO_ID]]; NSSortDescriptor * descriptor = [NSSortDescriptor sortDescriptorWithKey:@"title" ascending:YES]; request.sortDescriptors = [NSArray arrayWithObject:descriptor]; NSError *error = nil; NSArray *matches = [context executeFetchRequest:request error:&error]; if (!matches || [matches count] > 1) { // handle error } else if ( [matches count] == 0){ photo.title = [flickrInfo objectForKey:FLICKR_PHOTO_TITLE]; //Returns NULL when called NSLog(@"title = %@", photo.title); photo.uniqueID = [flickrInfo objectForKey:FLICKR_PHOTO_ID]; //Returns NULL when called NSLog(@"ID = %@", photo.uniqueID); } else { //If photo already exists this is called photo = [matches lastObject]; } return photo; }

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  • How to compare 2 lists and merge them in Python/MySQL?

    - by NJTechGuy
    I want to merge data. Following are my MySQL tables. I want to use Python to traverse though a list of both Lists (one with dupe = 'x' and other with null dupes). For instance : a b c d e f key dupe -------------------- 1 d c f k l 1 x 2 g h j 1 3 i h u u 2 4 u r t 2 x From the above sample table, the desired output is : a b c d e f key dupe -------------------- 2 g c h k j 1 3 i r h u u 2 What I have so far : import string, os, sys import MySQLdb from EncryptedFile import EncryptedFile enc = EncryptedFile( os.getenv("HOME") + '/.py-encrypted-file') user = enc.getValue("user") pw = enc.getValue("pw") db = MySQLdb.connect(host="127.0.0.1", user=user, passwd=pw,db=user) cursor = db.cursor() cursor2 = db.cursor() cursor.execute("select * from delThisTable where dupe is null") cursor2.execute("select * from delThisTable where dupe is not null") result = cursor.fetchall() result2 = cursor2.fetchall() for cursorFieldname in cursor.description: for cursorFieldname2 in cursor2.description: if cursorFieldname[0] == cursorFieldname2[0]: ### How do I compare the record with same key value and update the original row null field value with the non-null value from the duplicate? Please fill this void... cursor.close() cursor2.close() db.close() Thanks guys!

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