Search Results

Search found 8603 results on 345 pages for 'altering tables'.

Page 288/345 | < Previous Page | 284 285 286 287 288 289 290 291 292 293 294 295  | Next Page >

• how to use a generated dbml classes to deserialize xml via linq?

  - by Eelco Meuter

  Hi, I have a complex data structure, which I boiled down in a dbml file with one class and 6 one-to-many relations. This data must also be read via xml. The xml structure is something like: <table id=1> <column 1></column 1> <column n></column n> <m-n table x> <column 1></column 1> </m-n table x> </table> where the tag <m-n table x> is one of the six related tables. The idea is to generate an xsd based upon the dbml, which I can use to create and validate a xml. This xml can hopefully deserialized into the dbml classes. The question is: Can this be done? If so, how do I generate the xsd. I use a sql server express 2008 r2 as backend. Thanks in advance for your time!

  Read the article

• SQL2k8 T-SQL: Output into XML file

  - by Nai

  I have two tables Table Name: Graph UID1 UID2 ----------- 12 23 12 32 41 51 32 41 Table Name: Profiles NodeID UID Name ----------------- 1 12 Robs 2 23 Jones 3 32 Lim 4 41 Teo 5 51 Zacks I want to get an xml file like this: <graph directed="0"> <node id="1"> <att name="UID" value="12"/> <att name="Name" value="Robs"/> </node> <node id="2"> <att name="UID" value="23"/> <att name="Name" value="Jones"/> </node> <node id="3"> <att name="UID" value="32"/> <att name="Name" value="Lim"/> </node> <node id="4"> <att name="UID" value="41"/> <att name="Name" value="Teo"/> </node> <node id="5"> <att name="UID" value="51"/> <att name="Name" value="Zacks"/> </node> <edge source="12" target="23" /> <edge source="12" target="32" /> <edge source="41" target="51" /> <edge source="32" target="41" /> </graph> Thanks very much!

  Read the article

• Renaming TurboGears 2's Repoze Fields with TGAdmin

  - by William Chambers

  I've been working on renaming TurboGears 2's Repoze 'groups' field to 'roles' to free the namespace and db tables for other purposes. Also roles makes much more sense to me then groups because I have a strong Drupal background. Now I have found some of the docs to do this such as these: http://www.turbogears.org/2.1/docs/main/Auth/Customization.html#customizing-the-model-structure-assumed-by-the-quickstart http://code.gustavonarea.net/repoze.what-quickstart/#customizing-the-model-definition However these only go part of the way. I have made (I'm pretty sure at least, I've double checked a few times.) all the changes required as you can see in this diff. This seems to work fine however I've ran into a rather major issue with the TurboGears Admin system. I've tried http://turbogears.org/2.0/docs/main/Extensions/Admin/index.html and it didn't seem to make any difference, however I'm not 100% sure I did it correctly. The problem occurs when I attempt to go to localhost/admin/permissions/. It causes a Internal Server Error and outputs the following error. http://pastebin.com/YWMH3SiU This error does not happen on the Roles/Users pages and the permissions /edit/1 also works. I'm running kubuntu 10.04 with TG 2.1b2. (I'm running the beta mostly for easier mako support which is really important.) Any help would be very appreciated.

  Read the article

• Thinking Sphinx with Rails - Delta indexing seems to work fine for one model but not for the other

  - by hack3r

  I have 2 models User and Discussion. I have defined the indices for the models as below: For the User model: define_index do indexes email indexes first_name indexes last_name, :sortable => true indexes groups(:name), :as => :group_names has "IF(email_confirmed = true and status = 'approved', true, false)", :as => :approved_user, :type => :boolean has "IF(email_confirmed = true and (status = 'approved' or status='blocked'), true, false)", :as => :approved_or_blocked_user, :type => :boolean has points, :type => :integer has created_at, :type => :datetime has user(:id) set_property :delta => true end For the Discussion model: define_index do indexes title indexes description indexes category(:title), :as => :category_title indexes tags(:title), :as => :tag_title has "IF(publish_to_blog = true AND sticky = false, true, false)", :as => :publish_to_main, :type => :boolean has created_at has updated_at, :type => :datetime has recent_activity_at, :type => :datetime has views_count, :type => :integer has featured has publish_to_blog has sticky set_property :delta => true end I have added a delta column to both tables as per the documentation. My problem is that delta indexing works only for the Discussion model and not for the User model. For ex: When I update the 'title' of a discussion, I can see the thinking sphinx is rotating the indices etc. (as is evident from the logs). But when I update the 'first_name' or the 'last_name' of a user, nothing happens. The User model also has a has_many :through association through a model called GroupsUser. I have setup a after_save on the GroupsUser as follows: def set_user_delta_flag user.delta = true user.save end Even this doesn't seem to trigger delta indexing on the User model. A similar setup for the Discussion model works perfectly! Can anyone tell me why this is happening?

  Read the article

• Why put a DAO layer over a persistence layer (like JDO or Hibernate)

  - by Todd Owen

  Data Access Objects (DAOs) are a common design pattern, and recommended by Sun. But the earliest examples of Java DAOs interacted directly with relational databases -- they were, in essence, doing object-relational mapping (ORM). Nowadays, I see DAOs on top of mature ORM frameworks like JDO and Hibernate, and I wonder if that is really a good idea. I am developing a web service using JDO as the persistence layer, and am considering whether or not to introduce DAOs. I foresee a problem when dealing with a particular class which contains a map of other objects: public class Book { // Book description in various languages, indexed by ISO language codes private Map<String,BookDescription> descriptions; } JDO is clever enough to map this to a foreign key constraint between the "BOOKS" and "BOOKDESCRIPTIONS" tables. It transparently loads the BookDescription objects (using lazy loading, I believe), and persists them when the Book object is persisted. If I was to introduce a "data access layer" and write a class like BookDao, and encapsulate all the JDO code within this, then wouldn't this JDO's transparent loading of the child objects be circumventing the data access layer? For consistency, shouldn't all the BookDescription objects be loaded and persisted via some BookDescriptionDao object (or BookDao.loadDescription method)? Yet refactoring in that way would make manipulating the model needlessly complicated. So my question is, what's wrong with calling JDO (or Hibernate, or whatever ORM you fancy) directly in the business layer? Its syntax is already quite concise, and it is datastore-agnostic. What is the advantage, if any, of encapsulating it in Data Access Objects?

  Read the article

• How do you map a DateTime property to 2 varchar columns in the database with NHibernate (Fluent)?

  - by gabe

  I'm dealing with a legacy database that has date and time fields as char(8) columns (formatted yyyyMMdd and HH:mm:ss, respectively) in some of the tables. How can i map the 2 char columns to a single .NET DateTime property? I have tried the following, but i get a "can't access setter" error of course because DateTime Date and TimeOfDay properties are read-only: public class SweetPocoMannaFromHeaven { public virtual DateTime? FileCreationDateTime { get; set; } } . mapping.Component<DateTime?>(x => x.FileCreationDateTime, dt => { dt.Map(x => x.Value.Date, "file_creation_date"); dt.Map(x => x.Value.TimeOfDay, "file_creation_time"); }); I have also tried defining a IUserType for DateTime, but i can't figure it out. I've done a ton of googling for an answer, but i can't figure it out still. What is my best option to handle this stupid legacy database convention? A code example would be helpful since there's not much out for documentation on some of these more obscure scenarios.

  Read the article

• How to port an Ajax CMS based on metadata in Asp.Net MVC?

  - by Maushu

  I'm maintaining a CMS where I have this feeling it was made in the age of dinosaurs (Asp.net 1.0?) and decided to upgrade it with Asp.Net MVC and jQuery. But I have some problems regarding the design/specifications of the CMS which I cannot change. The CMS The CMS uses JavaScript. Alot. As in "I don't load pages, I request new pages using Ajax and render the information using javascript" alot. Not to mention the animations, the weird horizontal apresentation of structures... anyways, besides the first page (that is the login page) every other "page" is just data requested from a WebService that comes with the website. Would MVC have any problems with this design? The Database The database is in a SQL Server 2k8 and, like the CMS, this part is also... interesting. Basically, the user can create data structures using metadata (and saved on the Structure table). These structures are saved on tables that are created (and regenerated when changed) at runtime using said metadata. I don't know how I would implement this part in MVC. The question is, can and should I convert this project to MVC? Any tips regarding the metadata and overuse of ajax?

  Read the article

• How do i write this jpql query? java

  - by Nitesh Panchal

  Hello, Say i have 5 tables, tblBlogs tblBlogPosts tblBlogPostComment tblUser tblBlogMember BlogId BlogPostsId BlogPostCommentId UserId BlogMemberId BlogTitle BlogId CommentText FirstName UserId PostTitle BlogPostsId BlogId BlogMemberId Now i want to retrieve only those blogs and posts for which blogMember has actually commented. So in short, how do i write this plain old sql :- Select b.BlogTitle, bp.PostTitle, bpc.CommentText from tblBlogs b Inner join tblBlogPosts bp on b.BlogId = bp.BlogId Inner Join tblBlogPostComment bpc on bp.BlogPostsId = bpc.BlogPostsId Inner Join tblBlogMember bm On bpc.BlogMemberId = bm.BlogMemberId Where bm.UserId = 1; As you can see, everything is Inner join, so only that row will be retrieved for which the user has commented on some post of some blog. So, suppose he has joined 3 blogs whose ids are 1,2,3 (The blogs which user has joined are in tblBlogMembers) but the user has only commented in blog 2 (of say BlogPostId = 1). So that row will be retrieved and 1,3 won't as it is Inner Join. How do i write this kind of query in jpql? In jpql, we can only write simple queries like say :- Select bm.blogId from tblBlogMember Where bm.UserId = objUser; Where objUser is supplied using :- em.find(User.class,1); Thus once we get all blogs(Here blogId represents a blog object) which user has joined, we can loop through and do all fancy things. But i don't want to fall in this looping business and write all this things in my java code. Instead, i want to leave that for database engine to do. So, how do i write the above plain sql into jpql? and what type of object the jpql query will return? because i am only selecting few fields from all table. In which class should i typecast the result to? I think i posted my requirement correctly, if i am not clear please let me know. Thanks in advance :).

  Read the article

• Updating join fields in an ORM command

  - by Jono

  I have a question about object relational updates on join fields. I am working on a project using codeigniter with datamapper dmz. But I think my problem is with general understanding of ORMs. So fell free to answer with any ORM you know. I have two tables, Goods and Tags. One good can have many tags. Everything is working, but I am looking for a way to merge tags. Meaning I decide I want to remove tag A and instead have everything that is tagged by it, now be tagged by tag B. I only have models for the goods and the tags. There is no separate model for the join relationship, as I believe these ORMs were designed to work. I know how to delete a tag. But I dont know how to reach into the join table to redirect the references since there is no model for the join table. I would rather use the ORM then issuing a raw SQL command.

  Read the article

• archiving strategies and limitations of data in a table

  - by Samuel

  Environment: Jboss, Mysql, JPA, Hibernate Our web application will be catering to a large amount of users (~ 1,000,000) and there are a lots of child table where user specific data are stored (e.g. personal, health, forum contributions ...). What would be the best practice to archive user & user specific information. [a] Would it be wise to move the archived user & user specific information to their respective tables within the same database (e.g. user_archive, user_forum_comments_archive ...) OR [b] Would you just mark the database entries with a flag in the original table(s) and just query only non archived entries. We have a unique constraint on User.loginid, how do you handle this requirement if the users are archived via 1-[a] (i.e if a user with loginid 'samuel' gets moved into the archive table and if a new user gets added with the same name in the original table, how would you prevent this. What would be the best strategy to address the unique key constraints. We have a requirement to selectively archive records and bring it back if necessary, will you rely on database tools are would you handle this via your persistence APIs exposed by the JPA entity model.

  Read the article

• desing pattern for related inputs

  - by curiousMo

  My question is a design question : let's say i have a data entry web page with 4 drop down lists, each depending on the previous one, and a bunch of text boxes. country (ddl), state (ddl), city (ddl), boro (ddl), address (txtBox), zipcode(txtbox). and an object that represents a datarow with a value for each. naturally the country, state, city and boro values will be values of primary keys of some lookup tables. when the user chooses to edits that record, i would load it from database and load it into the page. the issue that I have is how to streamline loading the ddls. i have some code that would grab the object, look thru its values and move them to their corresponding input controls in one shot. but in this case i will have to load possible values of country, then assign values, then load values of state, then assign value ans so on. I guess i am looking for an elegant solution. i am using asp.net, but i think it is irrelevant to the question. i am looking more into a design pattern. thanks

  Read the article

• Issue encondig java->xls

  - by Xerg

  This is not a pure java question and can also be related to HTML I've written a java servlet that queries a database table and shows the result as a html table. The user can also ask to receive the result as an Excel sheet. Im creating the Excel sheet by printing the same html table, but with the content-type of "application/vnd.ms-excel". The Excel file is created fine. The problem is that the tables may contain non-english data so I want to use a UTF-8 encoding. PrintWriter out = response.getWriter(); response.setContentType("application/vnd.ms-excel:ISO-8859-1"); //response.setContentType("application/vnd.ms-excel:UTF-8"); response.setHeader("cache-control", "no-cache"); response.setHeader("Content-Disposition", "attachment; filename=file.xls"); out.print(src); out.flush(); The non-english characters appear as garbage (áéíóú) Also I tried converting to bytes from String byte[] arrByte = src.getBytes("ISO-8859-1"); String result = new String(arrByte, "UTF-8"); But I Still getting garbage, What can I do?. Thanks

  Read the article

• server caching problem on ASP.NET MVC page

  - by Rita

  Hi I have server caching error on ASP.NET MVC Pages. The scenario is like this. I have two applications (1).External Website and (2).Internal Adminsite, both pointing to the same Database. There is one page called EditProfile Page on the External Website that registered customer can update his profile information like Firstname, Lastname and Address…etc. Similarly there is similar functionality on the Internal Adminsite on the page called CustomerProfile Page where the Site Admin can update all these fields. When the user updates the profile information from the Adminsite, those updates are not reflecting back to the Website. Now I tried restarting the Website on IIS and that din’t help. Again I tried both restarting the Website on IIS and opening a new browser, then those updates are reflecting back. I am wondering how I can come out of this caching problem without restarting the site and open a new browser window everytime? Are there any IIS settings that could help? This caching is happening only on couple of tables only and all the updates are showing up in the database. Appreciate your responses. Thanks

  Read the article

• Query Access and VB.NET

  - by yae

  Hi all: I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are vinculated with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obatin the price of the main product, but not runs. This query not returns any value SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5));

  Read the article

• NHibernate Child items query using Parent Id

  - by thorkia

  So I have a set up similar to this questions: Parent Child Setup Everything works great when saving the parent and the children. However, I seem to have a problem when selecting the children. I can't seem to get all the children with a specific parent. This fails with: NHibernate.QueryException: could not resolve property: ParentEntity_id of: Test.Data.ChildEntity Here is my code: public IEnumerable<ChildEntity> GetByParent(ParentEntity parent) { using (ISession session = OrmHelper.OpenSession()) { return session.CreateCriteria<ChildEntity>().Add(Restrictions.Eq("ParentEntity_id ", parent.Id)).List<ChildEntity>(); } } Any help in building a proper function to get all the items would be appreciated. Oh, I am using Fluent NHibernate to construct the mappings - version 1 RTM and NHibernate 2.1.2 GA If you need more information, let me know. As per you request, my fluent mappings: public ParentEntityMap() { Id(x => x.Id); Map(x => x.Name); Map(x => x.Code).UniqueKey("ukCode"); HasMany(x => x.ChildEntity).LazyLoad() .Inverse().Cascade.SaveUpdate(); } public ChildEntityMap() { Id(x => x.Id); Map(x => x.Amount); Map(x => x.LogTime); References(x => x.ParentEntity); } That maps to the following 2 tables: CREATE TABLE "ParentEntity" ( Id integer, Name TEXT, Code TEXT, primary key (Id), unique (Code) ) CREATE TABLE "ChildEntity" ( Id integer, Amount NUMERIC, LogTime DATETIME, ParentEntity_id INTEGER, primary key (Id) ) The data store in SQLite.

  Read the article

• PHP Post Count in Forum

  - by Chris

  I'm currently desiging a forum application, I considered using a premade but decided against it as it's useful for me to learn some of the techniques. So I've written a fairly full featured forum... great. One of the problems I want to solve is to include user data for each post, at the minute the post table includes the poster ID (obviously) and I added the poster's username at a later date so I didn't have to query the User DB for X number of posts in a thread. However, it's become apparent I now want to do this, usernames don't need to update retrospectively, however avatars, sigs, and especially post counts need to update actively, so data in some form needs keeping up to date somewhere... What would be a good way of implementing this? I obviously don't want to include any more user data on the Posts DB table than necessary, but I'm struggling to find an easy way to do this short of querying the DB for each post in a thread, which is potentially going to create a lot of traffic. How have other people solved this, I've been examining the code on some other open source apps but I can't find what I'm looking for. Is it possible to select multiple records in one query? In which case I could build an array dynamically on each page request (eg 'SQL blah blah' then a for each loop to insert the ID's). Could I join the tables each time? Do I submit a query for each post? Hmm.

  Read the article

• How do I make software that preserves database integrity and correctness?

  - by user287745

  I have made an application project in Visual Studio 2008 C#, SQL Server from Visual Studio 2008. The database has like 20 tables and many fields in each. I have made an interface for adding deleting editing and retrieving data according to predefined needs of the users. Now I have to Make to project into software which I can deliver to my professor. That is, he can just double click the icon and the software simply starts. No Visual Studio 2008 needed to start the debugging. The database will be on one powerful computer (dual core latest everything Windows XP) and the user will access it from another computer connected using LAN. I am able to change the connection string to the shared database using Visual Studio 2008/ debugger whenever the server changes but how am I supposed to do that when it's software? There will by many clients. Am I supposed to give the same software to every one, so they all can connect to the database? How will the integrity and correctness of the database be maintained? I mean the db.mdf file will be in a folder which will be shared with read and write access. So it's not necessary that only one user will write at a time. So is there any coding for this or?

  Read the article

• multithreading issue

  - by vbNewbie

  I have written a multithreaded crawler and the process is simply creating threads and having them access a list of urls to crawl. They then access the urls and parse the html content. All this seems to work fine. Now when I need to write to tables in a database is when I experience issues. I have 2 declared arraylists that will contain the content each thread parse. The first arraylist is simply the rss feed links and the other arraylist contains the different posts. I then use a for each loop to iterate one while sequentially incrementing the other and writing to the database. My problem is that each time a new thread accesses one of the lists the content is changed and this affects the iteration. I tried using nested loops but it did not work before and this works fine using a single thread.I hope this makes sense. Here is my code: SyncLock dlock For Each l As String In links finallinks.Add(l) Next End SyncLock SyncLock dlock For Each p As String In posts finalposts.Add(p) Next End SyncLock ... Dim i As Integer = 0 SyncLock dlock For Each rsslink As String In finallinks postlink = finalposts.Item(i) i = i + 1 finallinks and finalposts are the two arraylists. I did not include the rest of the code which shows the threads working but this is the essential part where my error occurs which is basically here postlink = finalposts.Item(i) i = i + 1 ERROR: index was out of range. Must be non-negative and less than the size of the collection Is there an alternative?

  Read the article

• structure inside structure - c++ Error

  - by gamadeus

  First of all the error I am getting is of the type: Request for member 's' of struct1.struct1::struct2, which is of non class type '__u32' where: struct struct1 { struct x struct2; struct x struct3; struct x struct4; }; The usage is of the form: struct struct1 st1; st1.struct2.s = Value; Now my struct1 is: struct ip_mreq_source { struct in_addr imr_multiaddr; struct in_addr imr_sourceaddr; struct in_addr imr_interface; }; struct 'x' is in_addr Where: typedef uint32_t in_addr_t; struct in_addr { in_addr_t s_addr; }; element 's' is the element s_addr in in_addr. My detailed error coming out of g++ (GCC 4.4.3) from the Android based compiler: arm-linux-androideabi-g++ -MMD -MP -MF groupsock/GroupsockHelper.o.d.org -fpic -ffunction-sections -funwind-tables -fstack-protector -D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -Wno-psabi -march=armv5te -mtune=xscale -msoft-float -fno-exceptions -fno-rtti -mthumb -Os -fomit-frame-pointer -fno-strict-aliasing -finline- limit=64 -Igroupsock/include -Igroupsock/../UsageEnvironment/include -Iandroid- ndk-r5b/sources/cxx-stl/system/include -Igroupsock -DANDROID -Wa,--noexecstack -DANDROID_NDK -Wall -fexceptions -O2 -DNDEBUG -g -Iandroid-8/arch-arm/usr/include -c groupsock/GroupsockHelper.cpp -o groupsock/GroupsockHelper.o && rm -f groupsock/GroupsockHelper.o.d && mv groupsock/GroupsockHelper.o.d.org groupsock/GroupsockHelper.o.d groupsock/GroupsockHelper.cpp: In function 'Boolean socketJoinGroupSSM(UsageEnvironment&, int, netAddressBits, netAddressBits)': groupsock/GroupsockHelper.cpp:427: error: request for member 's_addr' in 'imr.ip_mreq_source::imr_multiaddr', which is of non-class type '__u32' groupsock/GroupsockHelper.cpp:428: error: request for member 's_addr' in 'imr.ip_mreq_source::imr_sourceaddr', which is of non-class type '__u32' groupsock/GroupsockHelper.cpp:429: error: request for member 's_addr' in 'imr.ip_mreq_source::imr_interface', which is of non-class type '__u32' I am not sure what is causing the error. Any pointers would be great - no pun intended. Thanks

  Read the article

• NHibernate CreateSqlQuery and object graph

  - by magellings

  Hello I'm a newbie to NHibernate. I'd like to make one sql query to the database using joins to my three tables. I have an Application with many Roles with many Users. I'm trying to get NHibernate to properly form the object graph starting with the Application object. For example, if I have 10 application records, I want 10 application objects and then those objects have their roles which have their users. What I'm getting however resembles a Cartesian product in which I have as many Application objects as total User records. I've looked into this quite a bit and am not sure if it is possible to form the application hierarchy correctly. I can only get the flattened objects to come back. It seems "maybe" possible as in my research I've read about "grouped joins" and "hierarchical output" with an upcoming LINQ to NHibernate release. Again though I'm a newbie. [Update Based on Frans comment in Ayende's post here I'm guessing what I want to do is not possible http://ayende.com/Blog/archive/2008/12/01/solving-the-select-n1-problem.aspx ] Thanks for you time in advance. Session.CreateSQLQuery(@"SELECT a.ID, a.InternalName, r.ID, r.ApplicationID, r.Name, u.UserID, u.RoleID FROM dbo.[Application] a JOIN dbo.[Roles] r ON a.ID = r.ApplicationID JOIN dbo.[UserRoleXRef] u ON u.RoleID = r.ID") .AddEntity("app", typeof(RightsBasedSecurityApplication)) .AddJoin("role", "app.Roles") .AddJoin("user", "role.RightsUsers") .List<RightsBasedSecurityApplication>().AsQueryable();

  Read the article

• SubSonic generated code and always filtering records

  - by cmroanirgo

  Hi, I have a table called "Users" that has a column called "deleted", a boolean indicating that the user is "Deleted" from the system (without actually deleting it, of course). I also have a lot of tables that have a FK to the Users.user_id column. Subsonic generates (very nicely) the code for all the foreign keys in a similar manner: public IQueryable<person> user { get { var repo=user.GetRepo(); return from items in repo.GetAll() where items.user_id == _user_id select items; } } Whilst this is good and all, is there a way to generate the code in such a way to always filter out the "Deleted" users too? In the office here, the only suggestion we can think of is to use a partial class and extend it. This is obviously a pain when there are lots and lots of classes using the User table, not to mention the fact that it's easy to inadvertently use the wrong property (User vs ActiveUser in this example): public IQueryable<User> ActiveUser { get { var repo=User.GetRepo(); return from items in repo.GetAll() where items.user_id == _user_id and items.deleted == 0 select items; } } Any ideas?

  Read the article

• Subqueries on Java GAE Datastore

  - by Dmitry

  I am trying to create a database of users with connection between users (friends list). There are 2 main tables: UserEntity (main field id) and FriendEntity with fields: - initiatorId - id of user who initiated the friendship - friendId - id of user who has been invited. Now I am trying to fetch all friends of one particular user and encountered some problems with using subqueries in JDO here. Logically the query should be something like this: SQL: SELECT * FROM UserEntity WHERE EXISTS (SELECT * FORM FriendEntity WHERE (initiatorId == UserEntity.id && friendId == userId) || (friendId == UserEntity.id && initiatorId == userId)) or SELECT * FROM UserEntity WHERE userId IN (SELECT * FROM FriendEntity WHERE initiatorId == UserEntity.id) OR userId IN (SELECT * FROM FriendEntity WHERE friendId == UserEntity.id) So to replicate the last query in JDOQL, I tried to do the following: Query friendQuery = pm.newQuery(FriendEntity.class); friendQuery.setFilter("initiatorId == uidParam"); friendQuery.setResult("friendId"); Query initiatorQuery = pm.newQuery(FriendEntity.class); initiatorQuery.setFilter("friendId == uidParam"); initiatorQuery.setResult("initiatorId"); Query query = pm.newQuery(UserEntity.class); query.setFilter("initiatorQuery.contains(id) || friendQuery.contains(id)"); query.addSubquery(initiatorQuery, "List initiatorQuery", null, "String uidParam"); query.addSubquery(friendQuery, "List friendQuery", null, "String uidParam"); query.declareParameters("String uidParam"); List<UserEntity> friends = (List<UserEntity>) query.execute(userId); In result I get the following error: Unsupported method while parsing expression. Could anyone help with this query please?

  Read the article

• Mysql InnoDB performance optimization and indexing

  - by Davide C

  Hello everybody, I have 2 databases and I need to link information between two big tables (more than 3M entries each, continuously growing). The 1st database has a table 'pages' that stores various information about web pages, and includes the URL of each one. The column 'URL' is a varchar(512) and has no index. The 2nd database has a table 'urlHops' defined as: CREATE TABLE urlHops ( dest varchar(512) NOT NULL, src varchar(512) DEFAULT NULL, timestamp timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, KEY dest_key (dest), KEY src_key (src) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 Now, I need basically to issue (efficiently) queries like this: select p.id,p.URL from db1.pages p, db2.urlHops u where u.src=p.URL and u.dest=? At first, I thought to add an index on pages(URL). But it's a very long column, and I already issue a lot of INSERTs and UPDATEs on the same table (way more than the number of SELECTs I would do using this index). Other possible solutions I thought are: -adding a column to pages, storing the md5 hash of the URL and indexing it; this way I could do queries using the md5 of the URL, with the advantage of an index on a smaller column. -adding another table that contains only page id and page URL, indexing both columns. But this is maybe a waste of space, having only the advantage of not slowing down the inserts and updates I execute on 'pages'. I don't want to slow down the inserts and updates, but at the same time I would be able to do the queries on the URL efficiently. Any advice? My primary concern is performance; if needed, wasting some disk space is not a problem. Thank you, regards Davide

  Read the article

• Adaptive user interface/environment algorithm

  - by WowtaH

  Hi all, I'm working on an information system (in C#) that (while my users use it) gathers statistical data on what pieces of information (tables & records) each user is requesting the most, and what parts of the interface he/she uses most. I'm using this statistical data to make the application adaptive to the user's needs, both in the way the interface presents itself (eg: tab/pane-ordering) as in the way of using the frequently viewed information to (eg:) show higher in search results/suggestion-lists. What i'm looking for is an algorithm/formula to determine the current 'hotness'/relevance of these objects for a specific user. A simple 'hitcounter' for each object won't be sufficient because the user might view some information quite frequently for a period of time, and then moving on to the next, making the old information less relevant. So i think my algorithm also needs some sort of sliding/historical principle to account for the changing popularity of the objects in the application over time. So, the question is: Does anybody have some sort of algorithm that accounts for that 'popularity over time' ? Preferably with some explanation on the parameters :) Thanks! PS I've looked at other posts like http://stackoverflow.com/questions/32397/popularity-algorithm but i could't quite port it to my specific case. Any help is appreciated.

  Read the article

• SQL Selects on subsets

  - by Adam

  I need to check if a row exists in a database; however, I am trying to find the way to do this that offers the best performance. This is best summarised with an example. Let's assume I have the following table: dbo.Person( FirstName varchar(50), LastName varchar(50), Company varchar(50) ) Assume this table has millions of rows, however ONLY the column Company has an index. I want to find out if a particular combination of FirstName, LastName and Company exists. I know I can do this: IF EXISTS(select 1 from dbo.Person where FirstName = @FirstName and LastName = @LastName and Company = @Company) Begin .... End However, unless I'm mistaken, that will do a full table scan. What I'd really like it to do is a query where it utilises the index. With the table above, I know that the following query will have great performance, since it uses the index: Select * from dbo.Person where Company = @Company Is there anyway to make the search only on that subset of data? e.g. something like this: select * from ( Select * from dbo.Person where Company = @Company ) where FirstName = @FirstName and LastName = @LastName That way, it would only be doing a table scan on a much narrower collection of data. I know the query above won't work, but is there a query that would? Oh, and I am unable to create temporary tables, as the user will only have read access.

  Read the article

< Previous Page | 284 285 286 287 288 289 290 291 292 293 294 295  | Next Page >