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  • WCF REST Question, Binding, Configuration

    - by Ethan McGee
    I am working on a WCF rest interface using json. I have wrapped the service in a windows service to host the service but I am now having trouble getting the service to be callable. I am not sure exactly what is wrong. The basic idea is that I want to host the service on a remote server so I want the service mapped to port localhost:7600 so that it can be invoked by posting data to [server_ip]:7600. The problem is most likely in the configuration file, since I am new to WCF and Rest I wasn't really sure what to type for the configuration so sorry if it's a total mess. I removed several chunks of code and comments to make it a little easier to read. These functions should have no bearing on the service since they call only C# functions. WCF Service Code using System; using System.Collections.Generic; using System.Linq; using System.ServiceModel; using System.ServiceModel.Activation; using System.ServiceModel.Web; using System.Text; namespace PCMiler_Connect { public class ZIP_List_Container { public string[] ZIP_List { get; set; } public string Optimized { get; set; } public string Calc_Type { get; set; } public string Cross_International_Borders { get; set; } public string Use_Kilometers { get; set; } public string Hazard_Level { get; set; } public string OK_To_Change_Destination { get; set; } } [ServiceContract] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)] public class PCMiler_Webservice { [WebInvoke(Method = "POST", UriTemplate = "", ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json), OperationContract] public List<string> Calculate_Distance(ZIP_List_Container container) { return new List<string>(){ distance.ToString(), time.ToString() }; } } } XML Config File <?xml version="1.0" encoding="utf-8"?> <configuration> <system.serviceModel> <services> <service name="PCMiler_Connect.PCMiler_Webservice"> <endpoint address="" behaviorConfiguration="jsonBehavior" binding="webHttpBinding" bindingConfiguration="" contract="PCMiler_Connect.PCMiler_Webservice" /> <host> <baseAddresses> <add baseAddress="http://localhost:7600/" /> </baseAddresses> </host> </service> </services> <behaviors> <endpointBehaviors> <behavior name="jsonBehavior"> <enableWebScript/> </behavior> </endpointBehaviors> </behaviors> </system.serviceModel> </configuration> Service Wrapper using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Diagnostics; using System.Linq; using System.ServiceProcess; using System.ServiceModel; using System.Text; using System.Threading; namespace PCMiler_WIN_Service { public partial class Service1 : ServiceBase { ServiceHost host; public Service1() { InitializeComponent(); } protected override void OnStart(string[] args) { host = new ServiceHost(typeof(PCMiler_Connect.PCMiler_Webservice)); Thread thread = new Thread(new ThreadStart(host.Open)); } protected override void OnStop() { if (host != null) { host.Close(); host = null; } } } }

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  • Emacs key binding fallback

    - by rejeep
    Hey, I have a minor mode. If that mode is active and the user hits DEL, I want to do some action, but only if some condition holds. If the condition holds and the action is executed I want to do nothing more after that. But if the condition fails, I don't want to do anything and let the default DEL action execute. Not sure how I could solve this. But I guess I could do it in two ways: 1) I could rebind the DEL key to a function in the minor mode and then check if the conditions holds ot not. But then how do I know what the default command to DEL is? 2) I could add a pre command hook like this. Execute the command and then break the chain. But how do I break the chain? (add-hook 'pre-command-hook (lambda() (when (equal last-input-event 'backspace) ;; Do something and then stop (do not execute the ;; command that backspace is bound to) ))) In what way would you solve it? Thanks!

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  • How to make an entity out of a join table without primary key

    - by tputkonen
    I'm trying to generate JPA entities out of an existing database having an "interesting" design. Database has a table called UserSet, which can have links to several other UserSets. There is a one to many relation between UserSets and LinkedUserSets. LinkedUserSets also has one to one relation to UserSets. I tried to generate a JPA Entity out of the database structure using Dali JPA Tools. The resulting entity Linkeduserset misses @Id or @EmbeddedId annotation and thus failes to compile. As the resulting entity contains only two @JoinColumns (which cannot be marked as @Id), I have not so far found a way around this issue. Database structure can not be modified in any way. Is there a way to overcome this somehow? Relevant pars of create table statements: CREATE TABLE `LinkedUserSets` ( `UsrSetID` INT(11) NOT NULL DEFAULT '0' , `ChildID` INT(11) NOT NULL DEFAULT '0' , CONSTRAINT `fk_LinkedUserSets_UserSet1` FOREIGN KEY (`UsrSetID` ) REFERENCES `UserSet` (`UsrSetID` )); CREATE TABLE `UserSet` ( `UsrSetID` INT(11) NOT NULL AUTO_INCREMENT , PRIMARY KEY (`UsrSetID`), CONSTRAINT `fk_UserSet_LinkedUserSets1` FOREIGN KEY (`UsrSetID` ) REFERENCES `LinkedUserSets` (`ChildID` )); Generated entities: @Entity @Table(name="linkedusersets") public class Linkeduserset { //bi-directional many-to-one association to Userset @ManyToOne @JoinColumn(name="UsrSetID") private Userset userset1; //bi-directional one-to-one association to Userset @OneToOne @JoinColumn(name="ChildID") private Userset userset2; } @Entity @Table(name="userset") public class Userset { private static final long serialVersionUID = 1L; @Id @Column(name="UsrSetID") private int jngSetID; //bi-directional many-to-one association to Linkeduserset @OneToMany(mappedBy="userset1") private Set<Linkeduserset> linkedusersets; //bi-directional one-to-one association to Linkeduserset @OneToOne(mappedBy="userset2") private Linkeduserset linkeduserset; } Error message: Entity "Linkeduserset" has no Id or EmbeddedId

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  • Creating 3DES key from bytes

    - by AO
    I create a triple DES key from the a byte array ("skBytes") but when calling getEncoded on the triple DES key ("sk") and comparing it to the byte array, they differ! They are almost the same if you look at the console output, though. How would I create a triple DES key that is exactly as "skBytes"? byte[] skBytes = {(byte) 0x41, (byte) 0x0B, (byte) 0xF0, (byte) 0x9B, (byte) 0xBC, (byte) 0x0E, (byte) 0xC9, (byte) 0x4A, (byte) 0xB5, (byte) 0xCE, (byte) 0x0B, (byte) 0xEA, (byte) 0x05, (byte) 0xEF, (byte) 0x52, (byte) 0x31, (byte) 0xD7, (byte) 0xEC, (byte) 0x2E, (byte) 0x75, (byte) 0xC3, (byte) 0x1D, (byte) 0x3E, (byte) 0x61}; DESedeKeySpec keySpec = new DESedeKeySpec(skBytes); SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DESede"); SecretKey sk = keyFactory.generateSecret(keySpec); for(int i = 0; i < skBytes.length; i++) { System.out.println("(sk.getEncoded()[i], skBytes[i]) = (" + sk.getEncoded()[i] +", " + skBytes[i] + ")"); } Console output: (sk.getEncoded()[i], skBytes[i]) = (64, 65) (sk.getEncoded()[i], skBytes[i]) = (11, 11) (sk.getEncoded()[i], skBytes[i]) = (-15, -16) (sk.getEncoded()[i], skBytes[i]) = (-101, -101) (sk.getEncoded()[i], skBytes[i]) = (-68, -68) (sk.getEncoded()[i], skBytes[i]) = (14, 14) (sk.getEncoded()[i], skBytes[i]) = (-56, -55) (sk.getEncoded()[i], skBytes[i]) = (74, 74) (sk.getEncoded()[i], skBytes[i]) = (-75, -75) (sk.getEncoded()[i], skBytes[i]) = (-50, -50) (sk.getEncoded()[i], skBytes[i]) = (11, 11) (sk.getEncoded()[i], skBytes[i]) = (-22, -22) (sk.getEncoded()[i], skBytes[i]) = (4, 5) (sk.getEncoded()[i], skBytes[i]) = (-17, -17) (sk.getEncoded()[i], skBytes[i]) = (82, 82) (sk.getEncoded()[i], skBytes[i]) = (49, 49) (sk.getEncoded()[i], skBytes[i]) = (-42, -41) (sk.getEncoded()[i], skBytes[i]) = (-20, -20) (sk.getEncoded()[i], skBytes[i]) = (47, 46) (sk.getEncoded()[i], skBytes[i]) = (117, 117) (sk.getEncoded()[i], skBytes[i]) = (-62, -61) (sk.getEncoded()[i], skBytes[i]) = (28, 29) (sk.getEncoded()[i], skBytes[i]) = (62, 62) (sk.getEncoded()[i], skBytes[i]) = (97, 97)

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  • Insert MANY key value pairs fast into berkeley db with hash access

    - by Kungi
    Hi, i'm trying to build a hash with berkeley db, which shall contain many tuples (approx 18GB of key value pairs), but in all my tests the performance of the insert operations degrades drastically over time. I've written this script to test the performance: #include<iostream> #include<db_cxx.h> #include<ctime> #define MILLION 1000000 int main () { long long a = 0; long long b = 0; int passes = 0; int i = 0; u_int32_t flags = DB_CREATE; Db* dbp = new Db(NULL,0); dbp->set_cachesize( 0, 1024 * 1024 * 1024, 1 ); int ret = dbp->open( NULL, "test.db", NULL, DB_HASH, flags, 0); time_t time1 = time(NULL); while ( passes < 100 ) { while( i < MILLION ) { Dbt key( &a, sizeof(long long) ); Dbt data( &b, sizeof(long long) ); dbp->put( NULL, &key, &data, 0); a++; b++; i++; } DbEnv* dbep = dbp->get_env(); int tmp; dbep->memp_trickle( 50, &tmp ); i=0; passes++; std::cout << "Inserted one million --> pass: " << passes << " took: " << time(NULL) - time1 << "sec" << std::endl; time1 = time(NULL); } } Perhaps you can tell me why after some time the "put" operation takes increasingly longer and maybe how to fix this. Thanks for your help, Andreas

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  • How to bind Dictionary with ComboBox and textbox?

    - by younevertell
    I have a Dictionary, where Person is a class, defined below String role; public class Person { public string firstname{ get; set; } public string lastname{ get; set; } public string city{ get; set; } } my question is how to bind the Dictionary key: String with a ComboBox, menwhile. have the Dictionary value: Person connected with three textboxes. That is, once a key is selected in the ComboBox, the corresponding value, firstname, lastname, city are shown in the three textboxes respectively? Thanks in advance!

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  • Authentication using cookie key with asynchronous callback

    - by greg
    I need to write authentication function with asynchronous callback from remote Auth API. Simple authentication with login is working well, but authorization with cookie key, does not work. It should checks if in cookies present key "lp_login", fetch API url like async and execute on_response function. The code almost works, but I see two problems. First, in on_response function I need to setup secure cookie for authorized user on every page. In code user_id returns correct ID, but line: self.set_secure_cookie("user", user_id) does't work. Why it can be? And second problem. During async fetch API url, user's page has loaded before on_response setup cookie with key "user" and the page will has an unauthorized section with link to login or sign on. It will be confusing for users. To solve it, I can stop loading page for user who trying to load first page of site. Is it possible to do and how? Maybe the problem has more correct way to solve it? class BaseHandler(tornado.web.RequestHandler): @tornado.web.asynchronous def get_current_user(self): user_id = self.get_secure_cookie("user") user_cookie = self.get_cookie("lp_login") if user_id: self.set_secure_cookie("user", user_id) return Author.objects.get(id=int(user_id)) elif user_cookie: url = urlparse("http://%s" % self.request.host) domain = url.netloc.split(":")[0] try: username, hashed_password = urllib.unquote(user_cookie).rsplit(',',1) except ValueError: # check against malicious clients return None else: url = "http://%s%s%s/%s/" % (domain, "/api/user/username/", username, hashed_password) http = tornado.httpclient.AsyncHTTPClient() http.fetch(url, callback=self.async_callback(self.on_response)) else: return None def on_response(self, response): answer = tornado.escape.json_decode(response.body) username = answer['username'] if answer["has_valid_credentials"]: author = Author.objects.get(email=answer["email"]) user_id = str(author.id) print user_id # It returns needed id self.set_secure_cookie("user", user_id) # but session can's setup

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  • Database design and foreign keys: Where should they be added in related tables?

    - by Carvell Fenton
    I have a relatively simple subset of tables in my database for tracking something called sessions. These are academic sessions (think offerings of a particular program). The tables to represent a sessions information are: sessions session_terms session_subjects session_mark_item_info session_marks All of these tables have their own primary keys, and are like a tree, in that sessions have terms, terms have subjects, subjects have mark items, etc. So each on would have at least its "parent's" foreign key. My question is, design wise is it a good idea to include the sessions primary key in the other tables as a foreign key to easily select related session items, or is that too much redundency? If I include the session foreign key (or all parent foreign keys from tables up the heirarchy) in all the tables, I can easily select all the marks for a session. As an example, something like SELECT mark FROM session_marks WHERE sessionID=... If I don't, then I would have to combine selects with something like WHERE something IN (SELECT... Which approach is "more correct" or efficient? Thanks in advance!

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  • binding nested json object value to a form field

    - by Jack
    I am building a dynamic form to edit data in a json object. First, if something like this exists let me know. I would rather not build it but I have searched many times for a tool and have found only tree like structures that require entering quotes. I would be happy to treat all values as strings. This edit functionality is for end users so it needs to be easy an not intimidating. So far I have code that generates nested tables to represent a json object. For each value I display a form field. I would like to bind the form field to the associated nested json value. If I could store a reference to the json value I would build an array of references to each value in a json object tree. I have not found a way to do that with javascript. My last resort approach will be to traverse the table after edits are made. I would rather have dynamic updates but a single submit would be better than nothing. Any ideas? // the json in files nests only a few levels. Here is the format of a simple case, { "researcherid_id":{ "id_key":"researcherid_id", "description":"Use to retrieve bibliometric data", "url_template" :[ { "name": "Author Detail", "url": "http://www.researcherid.com/rid/${key}" } ] } } $.get('file.json',make_json_form); function make_json_form(response) { dataset = $.secureEvalJSON(response); // iterate through the object and generate form field for string values. } // Then after the form is edited I want to display the raw updated json (then I want to save it but that is for another thread) // now I iterate through the form and construct the json object // I would rather have the dataset object var updated on focus out after each edit. function show_json(form_id){ var r = {}; var el = document.getElementById(form_id); table_to_json(r,el,null); $('body').html(formattedJSON(r)); }

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  • Fastest way to modify a decimal-keyed table in MySQL?

    - by javanix
    I am dealing with a MySQL table here that is keyed in a somewhat unfortunate way. Instead of using an auto increment table as a key, it uses a column of decimals to preserve order (presumably so its not too difficult to insert new rows while preserving a primary key and order). Before I go through and redo this table to something more sane, I need to figure out how to rekey it without breaking everything. What I would like to do is something that takes a list of doubles (the current keys) and outputs a list of integers (which can be cast down to doubles for rekeying). For example, input {1.00, 2.00, 2.50, 2.60, 3.00} would give output {1, 2, 3, 4, 5). Since this is a database, I also need to be able to update the rows nicely: UPDATE table SET `key`='3.00' WHERE `key`='2.50'; Can anyone think of a speedy algorithm to do this? My current thought is to read all of the doubles into a vector, take the size of the vector, and output a new vector with values from 1 => doubleVector.size. This seems pretty slow, since you wouldn't want to read every value into the vector if, for instance, only the last n/100 elements needed to be modified. I think there is probably something I can do in place, since only values after the first non-integer double need to be modified, but I can't for the life of me figure anything out that would let me update in place as well. For instance, setting 2.60 to 3.00 the first time you see 2.50 in the original key list would result in an error, since the key value 3.00 is already used for the table.

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  • Fastest way to convert a list of doubles to a unique list of integers?

    - by javanix
    I am dealing with a MySQL table here that is keyed in a somewhat unfortunate way. Instead of using an auto increment table as a key, it uses a column of decimals to preserve order (presumably so its not too difficult to insert new rows while preserving a primary key and order). Before I go through and redo this table to something more sane, I need to figure out how to rekey it without breaking everything. What I would like to do is something that takes a list of doubles (the current keys) and outputs a list of integers (which can be cast down to doubles for rekeying). For example, input {1.00, 2.00, 2.50, 2.60, 3.00} would give output {1, 2, 3, 4, 5). Since this is a database, I also need to be able to update the rows nicely: UPDATE table SET `key`='3.00' WHERE `key`='2.50'; Can anyone think of a speedy algorithm to do this? My current thought is to read all of the doubles into a vector, take the size of the vector, and output a new vector with values from 1 => doubleVector.size. This seems pretty slow, since you wouldn't want to read every value into the vector if, for instance, only the last n/100 elements needed to be modified. I think there is probably something I can do in place, since only values after the first non-integer double need to be modified, but I can't for the life of me figure anything out that would let me update in place as well. For instance, setting 2.60 to 3.00 the first time you see 2.50 in the original key list would result in an error, since the key value 3.00 is already used for the table.

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  • SQL Server problems reading columns with a foreign key

    - by illdev
    I have a weird situation, where simple queries seem to never finish for instance SELECT top 100 ArticleID FROM Article WHERE ProductGroupID=379114 returns immediately SELECT top 1000 ArticleID FROM Article WHERE ProductGroupID=379114 never returns SELECT ArticleID FROM Article WHERE ProductGroupID=379114 never returns SELECT top 1000 ArticleID FROM Article returns immediately By 'returning' I mean 'in query analyzer the green check mark appears and it says "Query executed successfully"'. I sometimes get the rows painted to the grid in qa, but still the query goes on waiting for my client to time out - 'sometimes': SELECT ProductGroupID AS Product23_1_, ArticleID AS ArticleID1_, ArticleID AS ArticleID18_0_, Inventory_Name AS Inventory3_18_0_, Inventory_UnitOfMeasure AS Inventory4_18_0_, BusinessKey AS Business5_18_0_, Name AS Name18_0_, ServesPeople AS ServesPe7_18_0_, InStock AS InStock18_0_, Description AS Descript9_18_0_, Description2 AS Descrip10_18_0_, TechnicalData AS Technic11_18_0_, IsDiscontinued AS IsDisco12_18_0_, Release AS Release18_0_, Classifications AS Classif14_18_0_, DistributorName AS Distrib15_18_0_, DistributorProductCode AS Distrib16_18_0_, Options AS Options18_0_, IsPromoted AS IsPromoted18_0_, IsBulkyFreight AS IsBulky19_18_0_, IsBackOrderOnly AS IsBackO20_18_0_, Price AS Price18_0_, Weight AS Weight18_0_, ProductGroupID AS Product23_18_0_, ConversationID AS Convers24_18_0_, DistributorID AS Distrib25_18_0_, type AS Type18_0_ FROM Article AS articles0_ WHERE (IsDiscontinued = '0') AND (ProductGroupID = 379121) shows this behavior. I have no idea what is going on. Probably select is broken ;) I got a foreign key on ProductGroups ALTER TABLE [dbo].[Article] WITH CHECK ADD CONSTRAINT [FK_ProductGroup_Articles] FOREIGN KEY([ProductGroupID]) REFERENCES [dbo].[ProductGroup] ([ProductGroupID]) GO ALTER TABLE [dbo].[Article] CHECK CONSTRAINT [FK_ProductGroup_Articles] there are some 6000 rows and IsDiscontinued is a bit, not null, but leaving this condition out does not change the outcome. Anyone can tell me how to handle such a situation? More info, anyone? Additional Info: this does not seem to be restricted to this Foreign Key, but all/some referencing this entity.

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  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

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  • NHibernate One to One Foreign Key ON DELETE CASCADE

    - by xll
    I need to implement One-to-one association between Project and ProjecSettings using fluent NHibernate: public class ProjectMap : ClassMap<Project> { public ProjectMap() { Id(x => x.Id) .UniqueKey(MapUtils.Col<Project>(x => x.Id)) .GeneratedBy.HiLo("NHHiLoIdentity", "NextHiValue", "1000", string.Format("[EntityName] = '[{0}]'", MapUtils.Table<Project>())) .Not.Nullable(); HasOne(x => x.ProjectSettings) .PropertyRef(x => x.Project); } } public class ProjectSettingsMap : ClassMap<ProjectSettings> { public ProjectSettingsMap() { Id(x => x.Id) .UniqueKey(MapUtils.Col<ProjectSettings>(x => x.Id)) .GeneratedBy.HiLo("NHHiLoIdentity", "NextHiValue", "1000", string.Format("[EntityName] = '[{0}]'", MapUtils.Table<ProjectSettings>())); References(x => x.Project) .Column(MapUtils.Ref<ProjectSettings, Project>(p => p.Project, p => p.Id)) .Unique() .Not.Nullable(); } } This results in the following sql for Project Settings: CREATE TABLE ProjectSettings ( Id bigint PRIMARY KEY NOT NULL, Project_Project_Id bigint NOT NULL UNIQUE, /* Foreign keys */ FOREIGN KEY (Project_Project_Id) REFERENCES Project() ON DELETE NO ACTION ON UPDATE NO ACTION ); What I am trying to achieve is to have ON DELETE CASCADE for the FOREIGN KEY (Project_Project_Id), so that when the project is deleted through sql query, it's settings are deleted too. How can I achieve this ? EDIT: I know about Cascade.Delete() option, but it's not what I need. Is there any way to intercept the FK statement generation?

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  • A GUID as the MySQL table's Primary Key or as a separate column

    - by Ben
    I have a multi-process program that performs, in a 2 hour period, 5-10 million inserts to a 34GB table within a single Master/Slave MySQL setup (plus an equal number of reads in that period). The table in question has only 5 fields and 3 (single field) indexes. The primary key is auto-incrementing. I am far from a DBA, but the database appears to be crippled during this two hour period. So, I have a couple of general questions. 1) How much bang will I get out of batching these writes into units of 10? Currently, I am writing each insert serially because, after writing, I immediately need to know, in my program, the resulting primary key of each insert. The PK is the only unique field presently and approximating the order of insertion with something like a Datetime field or a multi-column value is not acceptable. If I perform a bulk insert, I won't know these IDs, which is a problem. So, I've been thinking about turning the auto-increment primary key into a GUID and enforcing uniqueness. I've also been kicking around the idea of creating a new column just for the purposes of the GUID. I don't really see the what that achieves though, that the PK approach doesn't already offer. As far as I can tell, the big downside to making the PK a randomly generated number is that the index would take a long time to update on each insert (since insertion order would not be sequential). Is that an acceptable approach for a table that is taking this number of writes? Thanks, Ben

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  • Fetching just the Key/id from a ReferenceProperty in App Engine

    - by ozone
    Hi SO, I could use a little help in AppEngine land... Using the [Python] API I create relationships like this example from the docs: class Author(db.Model): name = db.StringProperty() class Story(db.Model): author = db.ReferenceProperty(Author) story = db.get(story_key) author_name = story.author.name As I understand it, that example will make two datastore queries. One to fetch the Story and then one to deference the Author inorder to access the name. But I want to be able to fetch the id, so do something like: story = db.get(story_key) author_id = story.author.key().id() I want to just get the id from the reference. I do not want to have to deference (therefore query the datastore) the ReferenceProperty value. From reading the documentation it says that the value of a ReferenceProperty is a Key Which leads me to think that I could just call .id() on the reference's value. But it also says: The ReferenceProperty model provides features for Key property values such as automatic dereferencing. I can't find anything that explains when this referencing takes place? Is it safe to call .id() on the ReferenceProperty's value? Can it be assumed that calling .id() will not cause a datastore lookup?

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  • Merge DataGrid ColumnHeaders

    - by Vishal
    I would like to merge two column-Headers. Before you go and mark this question as duplicate please read further. I don't want a super-Header. I just want to merge two column-headers. Take a look at image below: Can you see two columns with headers Mobile Number 1 and Mobile Number 2? I want to show there only 1 column header as Mobile Numbers. Here is the XAML used for creating above mentioned dataGrid: <DataGrid Grid.Row="1" Margin="0,10,0,0" ItemsSource="{Binding Ledgers}" IsReadOnly="True" AutoGenerateColumns="False"> <DataGrid.Columns> <DataGridTextColumn Header="Customer Name" Binding="{Binding LedgerName}" /> <DataGridTextColumn Header="City" Binding="{Binding City}" /> <DataGridTextColumn Header="Mobile Number 1" Binding="{Binding MobileNo1}" /> <DataGridTextColumn Header="Mobile Number 2" Binding="{Binding MobileNo2}" /> <DataGridTextColumn Header="Opening Balance" Binding="{Binding OpeningBalance}" /> </DataGrid.Columns> </DataGrid> Update1: Update2 I have created a converter as follows: public class MobileNumberFormatConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { if (value != null && value != DependencyProperty.UnsetValue) { if (value.ToString().Length <= 15) { int spacesToAdd = 15 - value.ToString().Length; string s = value.ToString().PadRight(value.ToString().Length + spacesToAdd); return s; } return value.ToString().Substring(0, value.ToString().Length - 3) + "..."; } return ""; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } } I have used it in XAML as follows: <DataGridTextColumn Header="Mobile Numbers"> <DataGridTextColumn.Binding> <MultiBinding StringFormat=" {0} {1}"> <Binding Path="MobileNo1" Converter="{StaticResource mobileNumberFormatConverter}"/> <Binding Path="MobileNo2" Converter="{StaticResource mobileNumberFormatConverter}"/> </MultiBinding> </DataGridTextColumn.Binding> </DataGridTextColumn> The output I got: Update3: At last I got the desired output. Here is the code for Converter: public class MobileNumberFormatConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { if (value != null && value != DependencyProperty.UnsetValue) { if (parameter.ToString().ToUpper() == "N") { if (value.ToString().Length <= 15) { return value.ToString(); } else { return value.ToString().Substring(0, 12); } } else if (parameter.ToString().ToUpper() == "S") { if (value.ToString().Length <= 15) { int spacesToAdd = 15 - value.ToString().Length; string spaces = ""; return spaces.PadRight(spacesToAdd); } else { return "..."; } } } return ""; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } } Here is my XAML: <DataGridTemplateColumn Header="Mobile Numbers"> <DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBlock> <Run Text="{Binding MobileNo1, Converter={StaticResource mobileNumberFormatConverter}, ConverterParameter=N}" /> <Run Text="{Binding MobileNo1, Converter={StaticResource mobileNumberFormatConverter}, ConverterParameter=S}" FontFamily="Consolas"/> <Run Text=" " FontFamily="Consolas"/> <Run Text="{Binding MobileNo2, Converter={StaticResource mobileNumberFormatConverter}, ConverterParameter=N}" /> <Run Text="{Binding MobileNo2, Converter={StaticResource mobileNumberFormatConverter}, ConverterParameter=S}" FontFamily="Consolas"/> </TextBlock> </DataTemplate> </DataGridTemplateColumn.CellTemplate> </DataGridTemplateColumn> Output:

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  • Dictionaries with more than one key per value in Python

    - by nickname
    I am attempting to create a nice interface to access a data set where each value has several possible keys. For example, suppose that I have both a number and a name for each value in the data set. I want to be able to access each value using either the number OR the name. I have considered several possible implementations: Using two separate dictionaries, one for the data values organized by number, and one for the data values organized by name. Simply assigning two keys to the same value in a dictionary. Creating dictionaries mapping each name to the corresponding number, and vice versa Attempting to create a hash function that maps each name to a number, etc. (related to the above) Creating an object to encapsulate all three pieces of data, then using one key to map dictionary keys to the objects and simply searching the dictionary to map the other key to the object. None of these seem ideal. The first seems ugly and unmaintainable. The second also seems fragile. The third/fourth seem plausible, but seem to require either much manual specification or an overly complex implementation. Finally, the fifth loses constant-time performance for one of the lookups. In C/C++, I believe that I would use pointers to reference the same piece of data from different keys. I know that the problem is rather similar to a database lookup problem by a non-key column, however, I would like (if possible), to maintain the approximate O(1) performance of Python dictionaries. What is the most Pythonic way to achieve this data structure?

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  • assign characters to key combinations in XP or Visual Studio .Net

    - by cpj
    I'm running Mac OSX on a MacBookPro (UK keyboard). I run windows XP under parallels in a VM. I run Visual Studio .Net 2003 and 2008 in XP in the VM when i need to. I have English United Kingdom and English United states keyboards setup in XP. (they switch sometimes for no apparent reason) There is no hash "#" key on my mac's keyboard. However, in OSX I can get a hash with an alt+3 key combination. But In Windows XP... I can not make a "#" character. I can go to the character map in windows and copy a hash.. switch into OSX and copy a hash.. search in code and copy a hash.. but I can not make a hash in XP using my keyboard without typing U+0023: ... which you can imagine is annoying. coding anything with hash symbols is becoming a choir. Anyone got any advice or key mapping tricks I can use to get hash characters working in XP using my mac UK keyboard?

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  • INSERT..ON DUPLICATE KEY UPDATE - but NOT using the duplicate key to compare.

    - by calumbrodie
    I am trying to solve a problem I have inherited with poor treatment of different data sources. I have a user table that contains BOTH good and evil users. create table `users`( `user_id` int(13) NOT NULL AUTO_INCREMENT , `email` varchar(255) , `name` varchar(255) , PRIMARY KEY (`user_id`) ); In this table the primary key is currently set to be user_id. I have another table ('users_evil') which contains ONLY the evil users (all the users from this table are included in the first table) - the user_id's on this table do NOT correspond to those in the first table. I want to have all my users in one table, and simply flag which are good and which are evil. What I want to do is alter the user table and add a column ('evil') which defaults to 0. I then want to dump the data from my 'users_evil') table and then run an INSERT..ON DUPLICATE KEY UPDATE with this data into the first table (setting 'evil'=1 where the emails match) The problem is that the 'PK' is set to the user_id and not the 'email'. Any suggestions, or even another strategy to successfully achive this. Can I run this statement but treat another column as PK only for the duration of the statement.

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  • Updating a composite primary key

    - by VBCSharp
    I am struggling with the philosophical discussions about whether or not to use composite primary keys on my SQL Server database. I have always used the surrogate keys in the past and I am challenging myself by leaving my comfort zone to try something different. I have read many discussion but can't come to any kind of solution yet. The struggle I am having is when I have to update a record with the composite PK. For example, the record in questions is like this: ContactID, RoleID, EffectiveDate, TerminationDT. The PK in this case is the ContactID, RoleID, and EffectiveDate. TerminationDT can be null. If in my UI, the user changes the RoleID and then I need to update the record. Using the surrogate key I can do an Update Table Set RoleID = 1 WHERE surrogateID = Z. However, using the Composite Key way, once one of the fields in the composite key changes I have no way to reference the old record to update it without now maintaining somewhere in the UI a reference to the old values. I do not bind datasources in my UI. I open a connection, get the data and store it in a bucket, then close the connection. What are everyone's opinions? Thanks.

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  • Handling primary key duplicates in a data warehouse load

    - by Meff
    I'm currently building an ETL system to load a data warehouse from a transactional system. The grain of my fact table is the transaction level. In order to ensure I don't load duplicate rows I've put a primary key on the fact table, which is the transaction ID. I've encountered a problem with transactions being reversed - In the transactional database this is done via a status, which I pick up and I can work out if the transaction is being done, or rolled back so I can load a reversal row in the warehouse. However, the reversal row will have the same transaction ID and so I get a primary key violation. I've solved this for now by negating the primary key, so transaction ID 1 would be a payment, and transaction ID -1 (In the warehouse only) would be the reversal. I have considered an alternative of generating a BIT column, where 0 is normal and 1 is reversal, then making the PK the transaction ID and the BIT column. My question is, is this a good practice, and has anyone else encountered anything like this? For reference, this is a payment processing system, so values will not be modified, so there will only ever be transactions and reversals.

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  • Why can't we just use a hash of passphrase as the encryption key (and IV) with symmetric encryption algorithms?

    - by TX_
    Inspired by my previous question, now I have a very interesting idea: Do you really ever need to use Rfc2898DeriveBytes or similar classes to "securely derive" the encryption key and initialization vector from the passphrase string, or will just a simple hash of that string work equally well as a key/IV, when encrypting the data with symmetric algorithm (e.g. AES, DES, etc.)? I see tons of AES encryption code snippets, where Rfc2898DeriveBytes class is used to derive the encryption key and initialization vector (IV) from the password string. It is assumed that one should use a random salt and a shitload of iterations to derive secure enough key/IV for the encryption. While deriving bytes from password string using this method is quite useful in some scenarios, I think that's not applicable when encrypting data with symmetric algorithms! Here is why: using salt makes sense when there is a possibility to build precalculated rainbow tables, and when attacker gets his hands on hash he looks up the original password as a result. But... with symmetric data encryption, I think this is not required, as the hash of password string, or the encryption key, is never stored anywhere. So, if we just get the SHA1 hash of password, and use it as the encryption key/IV, isn't that going to be equally secure? What is the purpose of using Rfc2898DeriveBytes class to generate key/IV from password string (which is a very very performance-intensive operation), when we could just use a SHA1 (or any other) hash of that password? Hash would result in random bit distribution in a key (as opposed to using string bytes directly). And attacker would have to brute-force the whole range of key (e.g. if key length is 256bit he would have to try 2^256 combinations) anyway. So either I'm wrong in a dangerous way, or all those samples of AES encryption (including many upvoted answers here at SO), etc. that use Rfc2898DeriveBytes method to generate encryption key and IV are just wrong.

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  • NHibernate with string primary key and relationships

    - by John_
    I've have just been stumped with this problem for an hour and I annoyingly found the problem eventually. THE CIRCUMSTANCES I have a table which users a string as a primary key, this table has various many to one and many to many relationships all off this primary key. When searching for multiple items from the table all relationships were brought back. However whenever I tried to get the object by the primary key (string) it was not bringing back any relationships, they were always set to 0. THE PARTIAL SOLUTION So I looked into my logs to see what the SQL was doing and that was returning the correct results. So I tried various things in all sorts of random ways and eventually worked out it was. The case of the string being passed into the get method was not EXACTLY the same case as it was in the database, so when it tried to match up the relationship items with the main entity it was finding nothing (Or at least NHIbernate wasn't because as I stated above the SQL was actually returning the correct results) THE REAL SOLUTION Has anyone else come across this? If so how do you tell NHibernate to ignore case when matching SQL results to the entity? It is silly because it worked perfectly well before now all of a sudden it has started to pay attention to the case of the string.

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