Search Results

Search found 93649 results on 3746 pages for 'protector one'.

Page 669/3746 | < Previous Page | 665 666 667 668 669 670 671 672 673 674 675 676  | Next Page >

• Is there a way to automatically load navigational property using the .NET Entity Framework?

  - by René Wolferink

  Stepping away more and more from writing SQL for my applications, I decided to give the Entity Framework a try. However, I've run into something I believe is causing me to write more code than I think is strictly necessary. When I accessed some navigational properties, I discovered that all many-to-one relations (simple references) were null and all one-to-many and many-to-many relations (EntityCollections) were empty. For example: I have a User with a reference to a Group. When I have retieved a User, by using a simple select-by-id, the Group property is null. If I want to access the Group I have to manually load it (using User.GroupReference.Load()). So I added a GetGroup() method in User which checks whether the Group is loaded already and, if not, does so and then returns the Group. Now this will result in a lot of highly similar methods for all navigational properties. And it all results in the navigational properties not being used, only my custom-made Get"PropertyName"() method's are now being used. I don't want to expand my queries (linq to entities) to immediately load all these properties, because it's not always known at first what is needed. And besides, it would cause a lot of queries to have to be made. Is there a way to configure the Entity Framework to load these objects when they happen to not be present? So when I access User.Group and the group is not loaded yet, it is loaded automatically? Or am I stuck using my own Get"PropertyName"() method's as long as I'm trying to load objects only on demand (or "just-in-time")? Some extra info: I'm using VS2008 SP1 with .NET 3.5 SP1. The Entity Framework I'm using is the one that got shipped with it.

  Read the article

• SQLAlchemy Custom Type Which Contains Multiple Columns

  - by Kekoa

  I would like to represent a datatype as a single column in my model, but really the data will be stored in multiple columns in the database. I cannot find any good resources on how to do this in SQLAlchemy. I would like my model to look like this(this is a simplified example using geometry instead of my real problem which is harder to explain): class 3DLine(DeclarativeBase): start_point = Column(my.custom.3DPoint) end_point = Column(my.custom.3DPoint) This way I could assign an object with the (x, y, z) components of the point at once without setting them individually. If I had to separate each component, this could get ugly, especially if each class has several of these composite objects. I would combine the values into one encoded field except that I need to query each value separately at times. I was able to find out how to make custom types using a single column in the documentation. But there's no indication that I can map a single type to multiple columns. I suppose I could accomplish this by using a separate table, and each column would be a foreign key, but in my case I don't think it makes sense to have a one to one mapping for each point to a separate table, and this still does not give the ability to set the related values all at once.

  Read the article

• In Perl, how can I wait for threads to end in parallel?

  - by Pmarcoen

  I have a Perl script that launches 2 threads,one for each processor. I need it to wait for a thread to end, if one thread ends a new one is spawned. It seems that the join method blocks the rest of the program, therefore the second thread can't end until everything the first thread does is done which sort of defeats its purpose. I tried the is_joinable method but that doesn't seem to do it either. Here is some of my code : use threads; use threads::shared; @file_list = @ARGV; #Our file list $nofiles = $#file_list + 1; #Real number of files $currfile = 1; #Current number of file to process my %MSG : shared; #shared hash $thr0 = threads->new(\&process, shift(@file_list)); $currfile++; $thr1 = threads->new(\&process, shift(@file_list)); $currfile++; while(1){ if ($thr0->is_joinable()) { $thr0->join; #check if there are files left to process if($currfile <= $nofiles){ $thr0 = threads->new(\&process, shift(@file_list)); $currfile++; } } if ($thr1->is_joinable()) { $thr1->join; #check if there are files left to process if($currfile <= $nofiles){ $thr1 = threads->new(\&process, shift(@file_list)); $currfile++; } } } sub process{ print "Opening $currfile of $nofiles\n"; #do some stuff if(some condition){ lock(%MSG); #write stuff to hash } print "Closing $currfile of $nofiles\n"; } The output of this is : Opening 1 of 4 Opening 2 of 4 Closing 1 of 4 Opening 3 of 4 Closing 3 of 4 Opening 4 of 4 Closing 2 of 4 Closing 4 of 4

  Read the article

• Why does Ruby have Rails while Python has no central framework?

  - by yar

  This is a(n) historical question, not a comparison-between-languages question: This article from 2005 talks about the lack of a single, central framework for Python. For Ruby, this framework is clearly Rails. Why, historically speaking, did this happen for Ruby but not for Python? (or did it happen, and that framework is Django?) Also, the hypothetical questions: would Python be more popular if it had one, good framework? Would Ruby be less popular if it had no central framework? [Please avoid discussions of whether Ruby or Python is better, which is just too open-ended to answer.] Edit: Though I thought this is obvious, I'm not saying that other frameworks do not exist for Ruby, but rather that the big one in terms of popularity is Rails. Also, I should mention that I'm not saying that frameworks for Python are not as good (or better than) Rails. Every framework has its pros and cons, but Rails seems to, as Ben Blank says in the one of the comments below, have surpassed Ruby in terms of popularity. There are no examples of that on the Python side. WHY? That's the question.

  Read the article

• To implement a remote desktop sharing solution

  - by Cameigons

  Hi, I'm on planning/modeling phase to develop a remote desktop sharing solution, which must be web browser based. In other words: an user will be able to see and interact with someone's remote desktop using his web-browser. Everything the user who wants to share his desktop will need, besides his browser, is installing an add-in, which he's going to be prompted about when necessary. The add-in is required since (afaik) no browser technology allows desktop control from an app running within the browser alone. The add-in installation process must be as simple and transparent as possible to the user (similar to AdobeConnectNow, in case anyone's acquainted with it). The user can share his desktop with lots of people at the same time, but concede desktop control to only one of them at a time(makes no sense being otherwise). Project requirements: All technology employed must be open-source license compatible Both front ends are going to be in flash (browser) Must work on Linux, Windows XP(and later) and MacOSX. Must work at least with IE7(and later) and Firefox3.0(and later). At the very least, once the sharer's stream hits the server from where it'll be broadcast, hereon it must be broadcasted in flv (so I'm thinking whether to do the encoding at the client's machine (the one sharing the desktop) or send it in some other format to the server and encode it there). Performance and scalability are important: It must be able to handle hundreds of dozens of users(one desktop sharer, the rest viewers) We'll definitely be using red5. My doubts concern mostly implementing the desktop publisher side (add-in and streamer): 1) Are you aware of other projects that I could look into for ideas? (I'm aware of bigbluebutton.org and code.google.com/p/openmeetings) 2) Should I base myself on VNC ? 3) Bearing in mind the need to have it working cross-platform, what language should I go with? (My team is very used with java and I have some knowledge of C/C++, but anything goes really). 4) Any other advices are appreciated.

  Read the article

• Conditional references in .NET project, possible to get rid of warning?

  - by Lasse V. Karlsen

  I have two references to a SQLite assembly, one for 32-bit and one for 64-bit, which looks like this (this is a test project to try to get rid of the warning, don't get hung up on the paths): <Reference Condition=" '$(Platform)' == 'x64' " Include="System.Data.SQLite, Version=1.0.61.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139, processorArchitecture=AMD64"> <SpecificVersion>True</SpecificVersion> <HintPath>..\..\LVK Libraries\SQLite3\version_1.0.65.0\64-bit\System.Data.SQLite.DLL</HintPath> </Reference> <Reference Condition=" '$(Platform)' == 'x86' " Include="System.Data.SQLite, Version=1.0.65.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139, processorArchitecture=x86"> <SpecificVersion>True</SpecificVersion> <HintPath>..\..\LVK Libraries\SQLite3\version_1.0.65.0\32-bit\System.Data.SQLite.DLL</HintPath> </Reference> This produces the following warning: Warning 1 The referenced component 'System.Data.SQLite' could not be found. Is it possible for me to get rid of this warning? One way I've looked at it to just configure my project to be 32-bit when I develop, and let the build machine fix the reference when building for 64-bit, but this seems a bit awkward and probably prone to errors. Any other options? The reason I want to get rid of it is that the warning is apparently being picked up by TeamCity and periodically flagged as something I need to look into, so I'd like to get completely rid of it.

  Read the article

• Javascript private member on prototype...

  - by Wilq32

  Well I tried to figure out is this possible in any way. Here is code: a=function(text) { var b=text; if (!arguments.callee.prototype.get) arguments.callee.prototype.get=function() { return b; } else alert('already created!'); } var c=new a("test"); // creates prototype instance of getter var d=new a("ojoj"); // alerts already created alert(c.get()) // alerts test alert(d.get()) // alerts test from context of creating prototype function :( As you see I tried to create prototype getter. For what? Well if you write something like this: a=function(text) { var b=text; this.getText=function(){ return b} } ... everything should be fine.. but in fact every time I create object - i create getText function that uses memory. I would like to have one prototypical function lying in memory that would do the same... Any ideas? EDIT: I tried solution given by Christoph, and it seems that its only known solution for now. It need to remember id information to retrieve value from context, but whole idea is nice for me :) Id is only one thing to remember, everything else can be stored once in memory. In fact you could store a lot of private members this way, and use anytime only one id. Actually this is satisfying me :) (unless someone got better idea). someFunc = function() { var store = new Array(); var guid=0; var someFunc = function(text) { this.__guid=guid; store[guid++]=text; } someFunc.prototype.getValue=function() { return store[this.__guid]; } return someFunc; }() a=new someFunc("test"); b=new someFunc("test2"); alert(a.getValue()); alert(b.getValue());

  Read the article

• Stage shifts when using addChild?

  - by josh

  I'm having a very odd bug with ActionScript 3 in Flash CS4. I am adding movie clips to a stage in a for loop and then moving them out of view so that I can pull them in and remove them when I need them. I've narrowed down the issue to a point that I know that every time one of the movie clips are added to the stage using addChild(), the stage shifts to the right by one pixel. I know that sounds odd, but it's literally true... the 0 line on the y axis is shifted to the right one pixel every time the movie clip is added. I have no idea how this could be happening. Here's the code that is doing the work: private function setupSlides():void { for(x = 0; x < TOTAL_SLIDES; x++) { var ClassReference:Class = getDefinitionByName("Slide" + (x+1)) as Class; var s:MovieClip = new ClassReference() as MovieClip; s.x = 9999; s.y = 9999; addChild(s); slides[x] = s; } } Any thoughts?

  Read the article

• Question about Multicaste Delegates?

  - by IbrarMumtaz

  I am going through some exam questions for the 70-536 exam and an actual question one developer postedon his blog has popped up in my exam questions. I cannot remember what his answer was .... but below is the question: You need to write a multicast delegate that accepts a DateTime arguement and returns a bool value. Which code segment should you use? A: public delegate int PowerDeviceOn(bool, DateTime) B: public delegate bool PowerDeviceOn(Object, EventArgs) C: public delegate void PowerDeviceOn(DateTime) D: public delegate bool PowerDeviceOn(DateTime) The answer is A. Can someone please explain why? As I already did some research into this question a while ago and so I was sure that it was C, obviously now looking back at the question its clear that I did not read properly. As i was sure I had seen the same one before so I jumped to the most obvious one. A varitation on this question: You need to write a multicast delegate that accepts a DateTime arguement. Which code segment should you use? A: public delegate int PowerDeviceOn(bool, DateTime) B: public delegate bool PowerDeviceOn(Object, EventArgs) C: public delegate void PowerDeviceOn(DateTime) D: public delegate bool PowerDeviceOn(DateTime) Now this is another variation on this quesiton, it still has the same bogus sample answers, as they still kind work in throwing the exam taker off. Notice how by simply keeping the sample asnwers the same and by removing a small portion of the question text, the answer is C and not A. The variation has no official answer as I just conjured it up using the exam question as a baseplate. The answer is definately C. This time round its easy to see why C is correctr but the very first question I have an inkiling but as you know an inkling is not good enough in passing exams. Thanks For Reading.

  Read the article

• Most watched videos this week

  - by Jan Hancic

  I have a youtube like web-page where users upload&watch videos. I would like to add a "most watched videos this week" list of videos to my page. But this list should not contain just the videos that ware uploaded in the previous week, but all videos. I'm currently recording views in a column, so I have no information on when a video was watched. So now I'm searching for a solution to how to record this data. The first is the most obvious (and the correct one, as far as I know): have a separate table in which you insert a new line every time you want to record a new view (storing the ID of the video and the timestamp). I'm worried that I would quickly get huge amounts of data in this table, and queries using this table would be extremely slow (we get about 3 million views a month). The second solution isn't as flexible but is more easy on the database. I would add 7 columns to the "videos" table (one for each day of the week): views_monday, views_tuesday , views_wednesday, ... And increment the value in the correct column based on the day it is. And I would reset the current day's column to 0 at midnight. I could then easily get the most watched videos of the week by summing this 7 columns. What do you think, should I bother with the first solution or will the second one suffice for my case? If you have a better solution please share! Oh, I'm using MySQL.

  Read the article

• In perl, how can I call a method whose name I have in a string?

  - by Ryan Thompson

  I'm trying to write some abstract code for searching through a list of similar objects for the first one whose attributes match specific values. In order to do this, I need to call a bunch of accessor methods and check all their values one by one. I'd like to use an abstraction like this: sub verify_attribute { my ($object, $attribute_method, $wanted_value) = @_; if ( call_method($object, $attribute_method) ~~ $wanted_value ) { return 1; } else { return; } } Then I can loop through a hash whose keys are accessor method names and whose values are the values I'm looking for for those attributes. For example, if that hash is called %wanted, I might use code like this to find the object I want: my $found_object; FINDOBJ: foreach my $obj (@list_of_objects) { foreach my $accessor (keys %wanted) { next FINDOBJ unless verify_attribute($obj, $accessor, $wanted{$accessor}); } # All attrs verified $found_object = $obj; last FINDOBJ; } Of course, the only problem is that call_method does not exsit. Or does it? How can I call a method if I have a string containing its name? Or is there a better solution to this whole problem?

  Read the article

• What to call factory-like (java) methods used with immutable objects

  - by StaxMan

  When creating classes for "immutable objects" immutable meaning that state of instances can not be changed; all fields assigned in constructor) in Java (and similar languages), it is sometimes useful to still allow creation of modified instances. That is, using an instance as base, and creating a new instance that differs by just one property value; other values coming from the base instance. To give a simple example, one could have class like: public class Circle { final double x, y; // location final double radius; public Circle(double x, double y, double r) { this.x = x; this.y = y; this.r = r; } // method for creating a new instance, moved in x-axis by specified amount public Circle withOffset(double deltaX) { return new Circle(x+deltaX, y, radius); } } So: what should method "withOffset" be called? (note: NOT what its name ought to be -- but what is this class of methods called). Technically it is kind of a factory method, but somehow that does not seem quite right to me, since often factories are just given basic properties (and are either static methods, or are not members of the result type but factory type). So I am guessing there should be a better term for such methods. Since these methods can be used to implement "fluent interface", maybe they could be "fluent factory methods"? Better suggestions? EDIT: as suggested by one of answers, java.math.BigDecimal is a good example with its 'add', 'subtract' (etc) methods. Also: I noticed that there's this question (by Jon Skeet no less) that is sort of related (although it asks about specific name for method)

  Read the article

• PHP: problem rendering large images (error 321)

  - by JP19

  Hi ... its me again with a php problem :) Following is part of my PHP script which is rendering JPEG images. ... $tf=$requested_file; $image_type="jpeg"; header("Content-type: image/${image_type}"); $CMD="\$image=imagecreatefrom${image_type}('$tf'); image${image_type}(\$image);"; eval($CMD); exit; ... There is no syntactical error, because above code is working fine for small images, but for large images, it gives: Error 321 (net::ERR_INVALID_CHUNKED_ENCODING): Unknown error. in the browser. To be sure, I created two images using imagemagick from same source image - one resized to 10% of original and other 90%. http://mostpopularsports.net/images/misc/ttt10.jpg works http://mostpopularsports.net/images/misc/ttt90.jpg gives Error 301 in the browser. There is a related question with solution posted by OP here Error writing content through Apache. but I cannot understand how to make the fix. Can someome help me with it? I have looked at the headers in Chrome. For the first request, everything is fine. For the second request - the request headers are all garbled. Both images are jpeg (as they are created from imagemagick. But still to be sure I checked): misc/ttt10.jpg: JPEG image data, JFIF standard 1.01 misc/ttt90.jpg: JPEG image data, JFIF standard 1.01 Finally, the way I fixed is, remove the Transfer-Encoding: chunked header from the response. [This header was sent by apache only when the data was large enough]. (I had an internal proxy, so did it in the proxy script - otherwise one may need to do it in apache settings). There were some good answers and I have selected the one that helped me solve the problem best. thanks JP

  Read the article

• Problems with Threading in Python 2.5, KeyError: 51, Help debugging?

  - by vignesh-k

  I have a python script which runs a particular script large number of times (for monte carlo purpose) and the way I have scripted it is that, I queue up the script the desired number of times it should be run then I spawn threads and each thread runs the script once and again when its done. Once the script in a particular thread is finished, the output is written to a file by accessing a lock (so my guess was that only one thread accesses the lock at a given time). Once the lock is released by one thread, the next thread accesses it and adds its output to the previously written file and rewrites it. I am not facing a problem when the number of iterations is small like 10 or 20 but when its large like 50 or 150, python returns a KeyError: 51 telling me element doesn't exist and the error it points out to is within the lock which puzzles me since only one thread should access the lock at once and I do not expect an error. This is the class I use: class errorclass(threading.Thread): def __init__(self, queue): self.__queue=queue threading.Thread.__init__(self) def run(self): while 1: item = self.__queue.get() if item is None: break result = myfunction() lock = threading.RLock() lock.acquire() ADD entries from current thread to entries in file and REWRITE FILE lock.release() queue = Queue.Queue() for i in range(threads): errorclass(queue).start() for i in range(desired iterations): queue.put(i) for i in range(threads): queue.put(None) Python returns with KeyError: 51 for large number of desired iterations during the adding/write file operation after lock access, I am wondering if this is the correct way to use the lock since every thread has a lock operation rather than every thread accessing a shared lock? What would be the way to rectify this?

  Read the article

• Maven (EJB) project with client and server artifacts

  - by Cornel Masson

  Here's my variation on the "multiple artifacts from Maven build" question: I'm porting from Ant to Maven. My application is an EJB server that is packaged as an EAR, but it also exposes a client JAR for use by other client apps. This jar contains the EJB interfaces, facade class and some helpers. I know that the Maven way is to have one artifact per project (POM); however, both artifacts (server EAR and client JAR) need to be built from the same source tree - server and client share, for example, the EJB and 'home' interfaces. How do I do this in Maven? Do I have one project containing two POMs, say server-pom.xml & client-pom.xml? I was thinking I could also have a parent POM (pom.xml) that can be used to build both client and server with one foul swoop? However, the lifecycles diverge after the 'package' phase, since the server has to go through assembly (tar/gzip), while the client is done after 'package' and can simply be installed into the repository. Any advice/experience on the best way to approach this?

  Read the article

• Sql Server Replication: Snapshot vs Merge

  - by Zyphrax

  Background information Let's say I have two database servers, both SQL Server 2008. One is in my LAN (ServerLocal), the other one is on a remote hosting environment (ServerRemote). I have created a database on ServerLocal and have an exact copy of that database on ServerRemote. The database on ServerRemote is part of a web application and I would like to keep it's data up-to-date with the data in the database ServerLocal. ServerLocal is able to communicate with ServerRemote, this is one-way traffic. Communication from ServerRemote to ServerLocal isn't available. Current solution I thought it would be a nice solution to use replication. So I've made ServerLocal a publisher and subscriptions are pushed to the ServerRemote. This works fine, when a snapshot is transfered to ServerRemote the existing data will be purged and the ServerRemote database is once again an exact replica of the database on ServerLocal. The problem Records that exist on ServerRemote that don't exist on ServerLocal are removed. This doesn't matter for most of my tables but in some of my tables I'd like to keep the existing data (aspnet_users for instance), and update the records if necessary. What kind of replication fits my problem?

  Read the article

• How to optimize a postgreSQL server for a "write once, read many"-type infrastructure ?

  - by mhu

  Greetings, I am working on a piece of software that logs entries (and related tagging) in a PostgreSQL database for storage and retrieval. We never update any data once it has been inserted; we might remove it when the entry gets too old, but this is done at most once a day. Stored entries can be retrieved by users. The insertion of new entries can happen rather fast and regularly, thus the database will commonly hold several millions elements. The tables used are pretty simple : one table for ids, raw content and insertion date; and one table storing tags and their values associated to an id. User search mostly concern tags values, so SELECTs usually consist of JOIN queries on ids on the two tables. To sum it up : 2 tables Lots of INSERT no UPDATE some DELETE, once a day at most some user-generated SELECT with JOIN huge data set What would an optimal server configuration (software and hardware, I assume for example that RAID10 could help) be for my PostgreSQL server, given these requirements ? By optimal, I mean one that allows SELECT queries taking a reasonably little amount of time. I can provide more information about the current setup (like tables, indexes ...) if needed.

  Read the article

• Need help with threads in a client/server

  - by nunos

  For college, I am developing a local relay chat. I have to program a chat server and client that will only work on sending messages on different terminal windows on the same computer with threads and fifos. The fifos part I am having no trouble, the threads part is the one that is giving me some headaches. The server has one thread for receiving commands from a fifo (used by all clients) and another thread for each client that is connected. For each client that is connected I need to know a certain information. Firstly, I was using global variables, which worked as longs as there was only one client connected, which is much of a chat, to chat alone. So, ideally I would have some data like: -nickname -name -email -etc... per client that is connected. However, I don't know how to do that. I could create a client_data[MAX_NUMBER_OF_THREADS] where client_data was a struct with everything I needed to have access to, but this would require to, in every communication between server and client to ask for the id of the client in the array client_data and that does not seem very pratical I could also instantiate a client_data immediately after creating the thread but it would only be available in that block, and that is not very pratical either. As you can see I am in need of a little guidance here. Any comment, piece of code or link to any relevant information is greatly appreciated. Thanks.

  Read the article

• In mysql, is "explain ..." always safe?

  - by tye

  If I allow a group of users to submit "explain $whatever" to mysql (via Perl's DBI using DBD::mysql), is there anything that a user could put into $whatever that would make any database changes, leak non-trivial information, or even cause significant database load? If so, how? I know that via "explain $whatever" one can figure out what tables / columns exist (you have to guess names, though) and roughly how many records are in a table or how many records have a particular value for an indexed field. I don't expect one to be able to get any information about the contents of unindexed fields. DBD::mysql should not allow multiple statements so I don't expect it to be possible to run any query (just explain one query). Even subqueries should not be executed, just explained. But I'm not a mysql expert and there are surely features of mysql that I'm not even aware of. In trying to come up with a query plan, might the optimizer actual execute an expression in order to come up with the value that an indexed field is going to be compared against? explain select * from atable where class = somefunction(...) where atable.class is indexed and not unique and class='unused' would find no records but class='common' would find a million records. Might 'explain' evaluate somefunction(...)? And then could somefunction(...) be written such that it modifies data?

  Read the article

• Detect if any USB drive is detected or not using WinForm Application

  - by Pavan Kumar

  I want to do the following things in my application 1) I want to display whether any USB drive is inserted or not in my application to prompt the user to insert a USB drive. I just want to notify the user if any USB dirve is inserted else prompt him to insert one using a label or something (i want to avoid messagebox as it will keep appearing whenever a device is inserted or removed. It will be irritating for the end user) in my Visual C# WinForm Application. If any USB drive is present display "USB drive detected" in the label. The user may add one or more USB sticks but the status will remain same. When there is none then the status of the label will change to "No USB drives found.Please insert a USB drive". 2) When one or more USB drive is added the volume name with the drive letter for example "James(F:)" is added to the Combobox list. The combobox list also needs to remove the entry for the USB drive added in the list automatically when it is removed . So when there is no USB the list should be empty and the label will again prompt user to insert a USB stick or drive.

  Read the article

• LINQ to SQL - Insert yielding strange behavior.

  - by Isaac

  Hi, I'm trying to insert several newly created items to the database. I have a LINQ2SQL generated class called "Order". Inside order, there's a property called "OrderItems" which is also generated by LINQ2SQL and represents the Items of that Order. So far so good. The problem I'm having right now, is when I try to add more than one newly created OrderItem inside Order. I.E: Order o = orderWorker.GetById( 10 ); for( int i=0; i < 5; ++i ) { OrderItem oi =new OrderItem { Order = order, Price = 100, ShippingPrice = 100, ShippingMethod = ... }; o.OrderItems.Add( oi ); } context.SubmitChanges(); Unfortunately, only a single entity is being added. Yes, I checked the generated SQL by adding Context.Log = Console.Out, and yes, only one statement was created. Any clues? By the way I know I'm not using InsertOnSubmit, by the documentation says: You can explicitly request Inserts by using InsertOnSubmit. Alternatively, LINQ to SQL can infer Inserts by finding objects connected to one of the known objects that must be updated. For example, if you add an Untracked object to an EntitySet(TEntity) or set an EntityRef(TEntity) to an Untracked object, you make the Untracked object reachable by way of tracked objects in the graph. While processing SubmitChanges, LINQ to SQL traverses the tracked objects and discovers any reachable persistent objects that are not tracked. Such objects are candidates for insertion into the database. Thank you very much for your time.

  Read the article

• Table index design

  - by Swoosh

  I would like to add index(s) to my table. I am looking for general ideas how to add more indexes to a table. Other than the PK clustered. I would like to know what to look for when I am doing this. So, my example: This table (let's call it TASK table) is going to be the biggest table of the whole application. Expecting millions records. IMPORTANT: massive bulk-insert is adding data in this table table has 27 columns: (so far, and counting :D ) int x 9 columns = id-s varchar x 10 columns bit x 2 columns datetime x 5 columns INT COLUMNS all of these are INT ID-s but from tables that are usually smaller than Task table (10-50 records max), example: Status table (with values like "open", "closed") or Priority table (with values like "important", "not so important", "normal") there is also a column like "parent-ID" (self - ID) join: all the "small" tables have PK, the usual way ... clustered STRING COLUMNS there is a (Company) column (string!) that is something like "5 characters long all the time" and every user will be restricted using this one. If in Task there are 15 different "Companies" the logged in user would only see one. So there's always a filter on this one. Might be a good idea to add an index to this column? DATE COLUMNS I think they don't index these ... right? Or can / should be?

  Read the article

• Checkboxes in ADF are initially null, where I want them to be 0

  - by Mark Tielemans

  I am using ADF in JDeveloper and don´t have any experience with either of the two. Now I´ve run into quite some trouble yet, but for this particular thing I decided to consult the wisom of stackoverflow. The thing is, I have an edit form for an object that contains 3 checkboxes. The checked values are set to 1, unchecked to 0. In my database, the values are NOT NULL, and I want to keep it that way. The thing is, in the edit form, if the user submits the form leaving any boxes unchecked, it will result in an error, because the unchecked box values apparently remain null. Only after checking and then unchecking the boxes again, their values will be '0' rather than null. I've tried some things, including making the attributes mandatory in the domain BCD, but that just gives a bit more neat error message.. Any help would be greatly appreciated!! EDIT I made a little progress thanks to the guide provided by Joe, but still run into problems. I changed the values that should be checkboxes in my model, making them BOOLEANs where the table columns are NUMBERs (All are also mandatory and have a default value of 0). This automatically changed the corresponding View Object too. In the Application module, this now works great. It shows checkboxes, a checked one will return 1, an untouched one will return 0. However, I deleted the old form, and inserted a new one using the corresponding Data Control. I gave these values the checkbox type. I still had to edit the bindings (which I think reflects the problem, as this is not the case with, say, a model-level defined LOV) and gave them 1 for checked and 0 for unchecked. However, now apart from the original problem still occurring, also the checkboxes cannot be unchecked after checking, and return 0 when checked (and null when left untouched). Even though this has created new problems, it works correctly in my AM. Does someone know what I'm doing wrong in my Swing form?

  Read the article

• C++ polymorphism and slicing

  - by Draco Ater

  The following code, prints out Derived Base Base But I need every Derived object put into User::items, call its own print function, but not the base class one. Can I achieve that without using pointers? If it is not possible, how should I write the function that deletes User::items one by one and frees memory, so that there should not be any memory leaks? #include <iostream> #include <vector> #include <algorithm> using namespace std; class Base{ public: virtual void print(){ cout << "Base" << endl;} }; class Derived: public Base{ public: void print(){ cout << "Derived" << endl;} }; class User{ public: vector<Base> items; void add_item( Base& item ){ item.print(); items.push_back( item ); items.back().print(); } }; void fill_items( User& u ){ Derived d; u.add_item( d ); } int main(){ User u; fill_items( u ); u.items[0].print(); }

  Read the article

• Why do I get null objects in a many-to-many bag?

  - by Jim Geurts

  I have a bag defined for a many-to-many list: <class name="Author" table="Authors"> <id name="Id" column="AuthorId"> <generator class="identity" /> </id> <property name="Name" /> <bag name="Books" table="Author_Book_Map" where="IsDeleted=0" fetch="join"> <key column="AuthorId" /> <many-to-many class="Book" column="BookId" where="IsDeleted=0" /> </bag> </class> If I return all author objects using something like the following, I will get what initially appeared to be duplicate Author records: Session.Query<Author>().List<Author>() The extra author objects are created when an author is mapped to Book objects that have IsDeleted = 1 and IsDeleted = 0. Rather than creating one Author object with an enumerable that contains only the books with IsDeleted = 0, it will create two author objects. The first author object has a Books enumerable that contains books with IsDeleted = 0. The second author object will contain an enumerable of null book objects. Similarly, if an object only has one book map, and that map points to a book with IsDeleted = 1, then an author object is returned with a Books collection having one null object. I'm thinking part of the problem stems from the map table objects linking to rows that satisfy the where condition on the bag object but do not meet the many-to-many where condition. This is happening with NHibernate version 3.0.0.4980. Is this a configuration issue or something else?

  Read the article

< Previous Page | 665 666 667 668 669 670 671 672 673 674 675 676  | Next Page >