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  • Database design efficiency with 1 to many relationships limited 1 to 3

    - by Joe
    This is in mysql, but its a database design issue. If you have a one to many relationship, like a bank customer to bank-accounts, typically you would have the table that records the bank-account information have a foreign key that keeps track of the relationship between account and customer. Now this follows the 3rd normal form thing and is a widely accepted way of doing it. Now lets say that you are going to limit a user to only having 3 accounts. The current database implementation will support this and nothing would need to change. But another way to do this would have 3 coloms in the account table that have the id of the 3 respective accounts in them. By the way this violates 1st normal form of db design. The question is what would be the advantage and disadvantages of having the user account relationship recored in this way over the traditional?

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  • Best way to order by columns in relationships?

    - by Timmy
    im using sqlalchemy, and i have a few polymorphic tables, and i want to sort by a column in one of the relationship. i have tables a,b,c,d, with relationship a to b, b to c, c to d. a to b is one-to-many b to c and c to d are one-to-one, but polymorphic. given an item in table a, i will have a list of items b, c, d (all one to one). how do i use sqlalchemy to sort them by a column in table d?

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  • Traversing ORM relationships returns duplicate results

    - by NKing253
    I have 4 tables -- store, catalog_galleries, catalog_images, and catalog_financials. When I traverse the relationship from store --> catalog_galleries --> catalog_images in other words: store.getCatalogGallery().getCatalogImages() I get duplicate records. Does anyone know what could be the cause of this? Any suggestions on where to look? The store table has a OneToOne relationship with catalog_galleries which in turn has a OneToMany relationship with catalog_images and an eager fetch type. The store table also has a OneToMany relationship with catalog_financials.

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  • Insert Record by Drag & Drop from ADF Tree to ADF Tree Table

    - by arul.wilson(at)oracle.com
    If you want to create record based on the values Dragged from ADF Tree and Dropped on a ADF Tree Table, then here you go.UseCase DescriptionUser Drags a tree node from ADF Tree and Drops it on a ADF Tree Table node. A new row gets added in the Tree Table based on the source tree node, subsequently a record gets added to the database table on which Tree table in based on.Following description helps to achieve this using ADF BC.Run the DragDropSchema.sql to create required tables.Create Business Components from tables (PRODUCTS, COMPONENTS, SUB_COMPONENTS, USERS, USER_COMPONENTS) created above.Add custom method to App Module Impl, this method will be used to insert record from view layer.   public String createUserComponents(String p_bugdbId, String p_productId, String p_componentId, String p_subComponentId){    Row newUserComponentsRow = this.getUserComponentsView1().createRow();    try {      newUserComponentsRow.setAttribute("Bugdbid", p_bugdbId);      newUserComponentsRow.setAttribute("ProductId", new oracle.jbo.domain.Number(p_productId));      newUserComponentsRow.setAttribute("Component1", p_componentId);      newUserComponentsRow.setAttribute("SubComponent", p_subComponentId);    } catch (Exception e) {        e.printStackTrace();        return "Failure";    }        return "Success";  }Expose this method to client interface.To display the root node we need a custom VO which can be achieved using below query. SELECT Users.ACTIVE, Users.BUGDB_ID, Users.EMAIL, Users.FIRSTNAME, Users.GLOBAL_ID, Users.LASTNAME, Users.MANAGER_ID, Users.MANAGER_PRIVILEGEFROM USERS UsersWHERE Users.MANAGER_ID is NULLCreate VL between UsersView and UsersRootNodeView VOs.Drop ProductsView from DC as ADF Tree to jspx page.Add Tree Level Rule based on ComponentsView and SubComponentsView.Drop UsersRootNodeView as ADF Tree TableAdd Tree Level Rules based on UserComponentsView and UsersView.Add DragSource to ADF Tree and CollectionDropTarget to ADF Tree Table respectively.Bind CollectionDropTarget's DropTarget to backing bean and implement method of signature DnDAction (DropEvent), this method gets invoked when Tree Table encounters a drop action, here details required for creating new record are captured from the drag source and passed to 'createUserComponents' method. public DnDAction onTreeDrop(DropEvent dropEvent) {      String newBugdbId = "";      String msgtxt="";            try {          // Getting the target node bugdb id          Object serverRowKey = dropEvent.getDropSite();          if (serverRowKey != null) {                  //Code for Tree Table as target              String dropcomponent = dropEvent.getDropComponent().toString();              dropcomponent = (String)dropcomponent.subSequence(0, dropcomponent.indexOf("["));              if (dropcomponent.equals("RichTreeTable")){                RichTreeTable richTreeTable = (RichTreeTable)dropEvent.getDropComponent();                richTreeTable.setRowKey(serverRowKey);                int rowIndexTreeTable = richTreeTable.getRowIndex();                //Drop Target Logic                if (((JUCtrlHierNodeBinding)richTreeTable.getRowData(rowIndexTreeTable)).getAttributeValue()==null) {                  //Get Parent                  newBugdbId = (String)((JUCtrlHierNodeBinding)richTreeTable.getRowData(rowIndexTreeTable)).getParent().getAttributeValue();                } else {                  if (isNum(((JUCtrlHierNodeBinding)richTreeTable.getRowData(rowIndexTreeTable)).getAttributeValue().toString())) {                    //Get Parent's parent                              newBugdbId = (String)((JUCtrlHierNodeBinding)richTreeTable.getRowData(rowIndexTreeTable)).getParent().getParent().getAttributeValue();                  } else{                      //Dropped on USER                                          newBugdbId = (String)((JUCtrlHierNodeBinding)richTreeTable.getRowData(rowIndexTreeTable)).getAttributeValue();                  }                  }              }           }                     DataFlavor<RowKeySet> df = DataFlavor.getDataFlavor(RowKeySet.class);          RowKeySet droppedValue = dropEvent.getTransferable().getData(df);            Object[] keys = droppedValue.toArray();          Key componentKey = null;          Key subComponentKey = null;           // binding for createUserComponents method defined in AppModuleImpl class  to insert record in database.                      operationBinding = bindings.getOperationBinding("createUserComponents");            // get the Product, Component, Subcomponent details and insert to UserComponents table.          // loop through the keys if more than one comp/subcomponent is select.                   for (int i = 0; i < keys.length; i++) {                  System.out.println("in for :"+i);              List list = (List)keys[i];                  System.out.println("list "+i+" : "+list);              System.out.println("list size "+list.size());              if (list.size() == 1) {                                // we cannot drag and drop  the highest node !                                msgtxt="You cannot drop Products, please drop Component or SubComponent from the Tree.";                  System.out.println(msgtxt);                                this.showInfoMessage(msgtxt);              } else {                  if (list.size() == 2) {                    // were doing the first branch, in this case all components.                    componentKey = (Key)list.get(1);                    Object[] droppedProdCompValues = componentKey.getAttributeValues();                    operationBinding.getParamsMap().put("p_bugdbId",newBugdbId);                    operationBinding.getParamsMap().put("p_productId",droppedProdCompValues[0]);                    operationBinding.getParamsMap().put("p_componentId",droppedProdCompValues[1]);                    operationBinding.getParamsMap().put("p_subComponentId","ALL");                    Object result = operationBinding.execute();              } else {                    subComponentKey = (Key)list.get(2);                    Object[] droppedProdCompSubCompValues = subComponentKey.getAttributeValues();                    operationBinding.getParamsMap().put("p_bugdbId",newBugdbId);                    operationBinding.getParamsMap().put("p_productId",droppedProdCompSubCompValues[0]);                    operationBinding.getParamsMap().put("p_componentId",droppedProdCompSubCompValues[1]);                    operationBinding.getParamsMap().put("p_subComponentId",droppedProdCompSubCompValues[2]);                    Object result = operationBinding.execute();                  }                   }            }                        /* this.getCil1().setDisabled(false);            this.getCil1().setPartialSubmit(true); */                      return DnDAction.MOVE;        } catch (Exception ex) {          System.out.println("drop failed with : " + ex.getMessage());          ex.printStackTrace();                  /* this.getCil1().setDisabled(true); */          return DnDAction.NONE;          }    } Run jspx page and drop a Component or Subcomponent from Products Tree to UserComponents Tree Table.

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  • Problem creating a database with PHP PDO

    - by Leandro Alonso
    Hello guys, I'm having a problem with a SQL query in my PHP Application. When the user access it for the first time, the app executes this query to create all the database: CREATE TABLE `databases` ( `id` bigint(20) NOT NULL auto_increment, `driver` varchar(45) NOT NULL, `server` text NOT NULL, `user` text NOT NULL, `password` text NOT NULL, `database` varchar(200) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -------------------------------------------------------- -- -- Table structure for table `modules` -- CREATE TABLE `modules` ( `id` bigint(20) unsigned NOT NULL auto_increment, `title` varchar(100) NOT NULL, `type` varchar(150) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=29 ; -- -------------------------------------------------------- -- -- Table structure for table `modules_data` -- CREATE TABLE `modules_data` ( `id` bigint(20) NOT NULL auto_increment, `module_id` bigint(20) unsigned NOT NULL, `key` varchar(150) NOT NULL, `value` tinytext, PRIMARY KEY (`id`), KEY `fk_modules_data_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=184 ; -- -------------------------------------------------------- -- -- Table structure for table `modules_position` -- CREATE TABLE `modules_position` ( `user_id` bigint(20) unsigned NOT NULL, `tab_id` bigint(20) unsigned NOT NULL, `module_id` bigint(20) unsigned NOT NULL, `column` smallint(1) default NULL, `line` smallint(1) default NULL, PRIMARY KEY (`user_id`,`tab_id`,`module_id`), KEY `fk_modules_order_users` (`user_id`), KEY `fk_modules_order_tabs` (`tab_id`), KEY `fk_modules_order_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `tabs` -- CREATE TABLE `tabs` ( `id` bigint(20) unsigned NOT NULL auto_increment, `title` varchar(60) NOT NULL, `columns` smallint(1) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ; -- -------------------------------------------------------- -- -- Table structure for table `tabs_has_modules` -- CREATE TABLE `tabs_has_modules` ( `tab_id` bigint(20) unsigned NOT NULL, `module_id` bigint(20) unsigned NOT NULL, PRIMARY KEY (`tab_id`,`module_id`), KEY `fk_tabs_has_modules_tabs` (`tab_id`), KEY `fk_tabs_has_modules_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `users` -- CREATE TABLE `users` ( `id` bigint(20) unsigned NOT NULL auto_increment, `login` varchar(60) NOT NULL, `password` varchar(64) NOT NULL, `email` varchar(100) NOT NULL, `name` varchar(250) default NULL, `user_level` bigint(20) unsigned NOT NULL, PRIMARY KEY (`id`), KEY `fk_users_user_levels` (`user_level`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -------------------------------------------------------- -- -- Table structure for table `users_has_tabs` -- CREATE TABLE `users_has_tabs` ( `user_id` bigint(20) unsigned NOT NULL, `tab_id` bigint(20) unsigned NOT NULL, `order` smallint(2) NOT NULL, `columns_width` varchar(255) default NULL, PRIMARY KEY (`user_id`,`tab_id`), KEY `fk_users_has_tabs_users` (`user_id`), KEY `fk_users_has_tabs_tabs` (`tab_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `user_levels` -- CREATE TABLE `user_levels` ( `id` bigint(20) unsigned NOT NULL auto_increment, `level` smallint(2) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -------------------------------------------------------- -- -- Table structure for table `user_meta` -- CREATE TABLE `user_meta` ( `id` bigint(20) unsigned NOT NULL auto_increment, `user_id` bigint(20) unsigned default NULL, `key` varchar(150) NOT NULL, `value` longtext NOT NULL, PRIMARY KEY (`id`), KEY `fk_user_meta_users` (`user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -- Constraints for dumped tables -- -- -- Constraints for table `modules_data` -- ALTER TABLE `modules_data` ADD CONSTRAINT `fk_modules_data_modules` FOREIGN KEY (`module_id`) REFERENCES `modules` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; -- -- Constraints for table `modules_position` -- ALTER TABLE `modules_position` ADD CONSTRAINT `fk_modules_order_modules` FOREIGN KEY (`module_id`) REFERENCES `modules` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION, ADD CONSTRAINT `fk_modules_order_tabs` FOREIGN KEY (`tab_id`) REFERENCES `tabs` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION, ADD CONSTRAINT `fk_modules_order_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; -- -- Constraints for table `users` -- ALTER TABLE `users` ADD CONSTRAINT `fk_users_user_levels` FOREIGN KEY (`user_level`) REFERENCES `user_levels` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION; -- -- Constraints for table `user_meta` -- ALTER TABLE `user_meta` ADD CONSTRAINT `fk_user_meta_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; INSERT INTO `user_levels` VALUES(1, 10); INSERT INTO `user_levels` VALUES(2, 1); INSERT INTO `users` VALUES(1, 'admin', 'password', '[email protected]', NULL, 1); INSERT INTO `user_meta` VALUES (NULL, 1, 'last_tab', 1); In some environments i get this error: SQLSTATE[HY000]: General error: 1005 Can't create table 'dms.databases' (errno: 150) I tried everything that I could find on Google but nothing works. The strange part is that if I run this query in PhpMyAdmin he creates my database, without any error.

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  • Creating multiple relationships in rails with same datatypes

    - by Lowgain
    What I am trying to do is kind of like this: I have datatypes "user" and "article" for instance. I want to have relationships between these two, but in more than one way. So for instance, I'd like to let a user "like" or "bookmark" an article. So I need to have two relations in the database, one for users liking the article, and one for users bookmarking, so making a "user_article" table for instance won't be sufficient, correct? What is the best way of going about doing this?

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  • best way to store 1:1 user relationships in relational database

    - by aharon
    What is the best way to store user relationships, e.g. friendships, that must be bidirectional (you're my friend, thus I'm your friend) in a rel. database, e.g. MYSql? I can think of two ways: Everytime a user friends another user, I'd add two rows to a database, row A consisting of the user id of the innitiating user followed by the UID of the accepting user in the next column. Row B would be the reverse. You'd only add one row, UID(initiating user) followed by UID(accepting user); and then just search through both columns when trying to figure out whether user 1 is a friend of user 2. Surely there is something better?

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  • UML Class Relationships

    - by 01010011
    Hi, I would like to confirm whether I am on the right track when identifying common UML class relationships. For example, is the relationship between: 1 a stackoverflow member and his/her stackoverflow user account categorized as a composition relationship or an aggregation relationship? At first I thought it was an association because this member "has a" account. However on second thought, I am thinking its composition because each "part" (user account) belongs to only one whole (user) at a time, meaning for as long as I am logged into stackoverflow, I have to use this one and only account until I log off. If I log back onto stackoverflow with a different account then its composition again. Do you agree? 2 a database and a person's user account an aggregation relationship? I think so because 1 database (the whole) can store 0...* number of user accounts (the parts) but another database can store the same user accounts. Finally, can anyone recommend a website that specializes in designing code using UML? Thanks in advance

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  • Change an access Primary key with relationships

    - by DiegoMaK
    I have a database in access 2007 accdb extension , there are more or less 30-40 tables with related primary key "local_number". it is a text primary key with 10 lenght. How can I change the length of this primary key to 30 WITHOUT delete previosly all the 30 relationship. 2,A similar question. I need add a compose primary key to my PK "local_number". I need Add a "Date" as composed PK. Then access just allow this if I first delete all relationships. How can Avoid this warning and change my PK ignoring this message.

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  • How the number of indexes built on a table can impact performances?

    - by Davide Mauri
    We all know that putting too many indexes (I’m talking of non-clustered index only, of course) on table may produce performance problems due to the overhead that each index bring to all insert/update/delete operations on that table. But how much? I mean, we all agree – I think – that, generally speaking, having many indexes on a table is “bad”. But how bad it can be? How much the performance will degrade? And on a concurrent system how much this situation can also hurts SELECT performances? If SQL Server take more time to update a row on a table due to the amount of indexes it also has to update, this also means that locks will be held for more time, slowing down the perceived performance of all queries involved. I was quite curious to measure this, also because when teaching it’s by far more impressive and effective to show to attended a chart with the measured impact, so that they can really “feel” what it means! To do the tests, I’ve create a script that creates a table (that has a clustered index on the primary key which is an identity column) , loads 1000 rows into the table (inserting 1000 row using only one insert, instead of issuing 1000 insert of one row, in order to minimize the overhead needed to handle the transaction, that would have otherwise ), and measures the time taken to do it. The process is then repeated 16 times, each time adding a new index on the table, using columns from table in a round-robin fashion. Test are done against different row sizes, so that it’s possible to check if performance changes depending on row size. The result are interesting, although expected. This is the chart showing how much time it takes to insert 1000 on a table that has from 0 to 16 non-clustered indexes. Each test has been run 20 times in order to have an average value. The value has been cleaned from outliers value due to unpredictable performance fluctuations due to machine activity. The test shows that in a  table with a row size of 80 bytes, 1000 rows can be inserted in 9,05 msec if no indexes are present on the table, and the value grows up to 88 (!!!) msec when you have 16 indexes on it This means a impact on performance of 975%. That’s *huge*! Now, what happens if we have a bigger row size? Say that we have a table with a row size of 1520 byte. Here’s the data, from 0 to 16 indexes on that table: In this case we need near 22 msec to insert 1000 in a table with no indexes, but we need more that 500msec if the table has 16 active indexes! Now we’re talking of a 2410% impact on performance! Now we can have a tangible idea of what’s the impact of having (too?) many indexes on a table and also how the size of a row also impact performances. That’s why the golden rule of OLTP databases “few indexes, but good” is so true! (And in fact last week I saw a database with tables with 1700bytes row size and 23 (!!!) indexes on them!) This also means that a too heavy denormalization is really not a good idea (we’re always talking about OLTP systems, keep it in mind), since the performance get worse with the increase of the row size. So, be careful out there, and keep in mind the “equilibrium” is the key world of a database professional: equilibrium between read and write performance, between normalization and denormalization, between to few and too may indexes. PS Tests are done on a VMWare Workstation 7 VM with 2 CPU and 4 GB of Memory. Host machine is a Dell Precsioni M6500 with i7 Extreme X920 Quad-Core HT 2.0Ghz and 16Gb of RAM. Database is stored on a SSD Intel X-25E Drive, Simple Recovery Model, running on SQL Server 2008 R2. If you also want to to tests on your own, you can download the test script here: Open TestIndexPerformance.sql

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  • Deleting entity with child relationships using .Net Entity Framework problem

    - by Am
    My God, EF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this: if (!object.childobjects.IsLoaded) object.childobjects.Load(); but once I do the following I get errors related to the relationships: modelcontext.DeleteObject(object); modelcontext.SaveChanges(); Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 12 I've tried few variations and all of them throw exceptions.

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  • Core Data Relationships in pre-populated SQLite database

    - by Cardinal
    Hi All, I'm new to Core Data. Currently I have following tables on hand: tbl_teahcer tbl_student tbl_course tbl_student_course_map ----------- ----------- ---------- ---------------------- teacher_id student_id course_id student_id name name name course_id teahcer_id And I'm going to make the xcdatamodel as below: Course Teacher ------ ------- name name teacher <<----------> courses students <<---| | Student | ------- | name |----->> courses My questions are as follows: As I'd like to create TableView for Cource Entity, is it a must to create the Inverse Relationship from Teacher to Course, and Student to Course? What is the beneit for having the Inverse Relationship? I got some pre-defined data on hand, and I'd like to create a SQLite storage for pre-populated source. How can I set up the relationships (both directions) in SQLite? Thank you for your help! Regards, Cardinal

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  • Sql Server 2008 Cross-database table linking (relationships)

    - by Alex
    Hi guys, I have a bit of an issue, and to be honest I don't think there's an answer, but I'll give it a try anyway. So I have two databases [A]-Company and [B]-Product. Both databases have a Country table which is then linked to other tables in each individual database. The problem is that the data between the two Country tables is a complete duplicate. So, I essentially have to duplicate some of the relationships in each database, and maintenance on top of that is just difficult... So, I'm curious is there a way to create a cross-database relationship between tables so I can have only one set of Country+Helper tables that govern both databases? Thanks in advance!

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  • How to manually manage Core Data relationships when deleting

    - by Simon
    I have a Core Data entity, which contains a relationship to another entity. Under certain circumstances, I need to delete the managed objects in the relationship, and at other times no action needs to be taken. I have the Delete Rule on the entity is No Action because of this manual management. The problem I have is, where is the best place to enforce these rules? I cannot see any suitable messages to override on NSManagedObject (something that might notify the object it has been deleted and should clear up its relationships). I would rather not do it higher up in the application logic, because the entity objects can get deleted from array controllers and at different points in the applications, making it necessary to stuff relationship update code at all those levels.

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  • Looking for a free tool to visualize object relationships for C#

    - by vfilby
    Here is my ideal solution: a free tool that reads a .csporj or .sln and generates a pretty picture that shows all the objects and how they are related. By relationships, I don't mean inheritance but rather dependency. For example, if we have a Car object and Car has a member variable Wheel, I would like that Car depends on Wheel to be visualized in the graph. I know visual studio can do inheritance graphs, but that is only half of what I am looking for. Is what I am looking for possible? Are there any tools that do something similar? Related question for java: http://stackoverflow.com/questions/1824261/are-there-any-tools-to-visualize-the-objects-being-used-in-a-program

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  • Relationships via Email Rather Than User List

    - by Bob Lerner
    I'm new at Drupal, so I may have missed a solution despite a lot of research: I want users to be able to invite non-users and other users into a named relationship they've set up (using e.g. the Friendlist or User Relationships module) using only email addresses and not the user list. I believe that invitations from both of those modules are done only after the inviter selects the invitee after selecting the invitee from a list of all users. Frankly, I would be surprised if no email solution exists since a large site's user list would be daunting. Does anyone know if this is possible using Organic Groups? Thanks very much.

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  • Other link relationships and impact to the SEO

    - by haha
    Example other link relationships <head> <link rel='index' title='Main Title' href='http://domain.com/' /> <link rel='start' title='Part Three' href='http://domain.com/part-3/' /> <link rel='prev' title='Part Two' href='http://domain.com/part-2/' /> <link rel='next' title='Part Four' href='http://domain.com/part-4/' /> </head> Questions Have a big impact to make my site get a nice rank to Search Engine?

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  • Representing parent-child relationships in SharePoint lists

    - by Chris Farmer
    I need to create some functionality in our SharePoint app that populates a list or lists with some simple hierarchical data. Each parent record will represent a "submission" and each child record will be a "submission item." There's a 1-to-n relationship between submissions and submission items. Is this practical to do in SharePoint? The only types of list relationships I've done so far are lookup columns, but this seems a bit different. Also, once such a list relationship is established, then what's the best way to create views on this kind of data. I'm almost convinced that it'd be easier just to write this stuff to an external database, but I'd like to give SharePoint a shot in order to take advantage of the automated search capabilities.

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  • IndexedDB and Relationships

    - by Josh Johnson
    Can I create relationships between my object stores in IndexedDB? For example, I have two object stores: artist and album. An artist has a one-to-many relationship with an album. album.artistId relates the album to artist.id. I'm thinking along the lines of Hibernate here. I would like to do a query for artists and have the albums belonging to that artist returned as an array called artists on the album object. artist.albums = [];

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  • Entity Framework 4 and 0:1, 0:1 relationships

    - by Eric J.
    I'm using the Model First approach with EF 4 and hit a snag with two tables, Participant (singular because pre-existing from another app) and ActiveParticipants. A Participant may or may not be associated with exactly one ActiveParticipant and vice versa. When I create an association, everything seems to go well on the surface, but then I get a runtime error complaining that Participant does not contain the column ActiveParticipant_Id. It does contain a column ActiveParticipantId (no underscore). When I view the diagram as XML, there's a line like this: <Property Name="ActiveParticipant_Id" Type="uniqueidentifier" Nullable="true" /> Why is it adding an underscore? Is there anything special I need to do for 0:1, 0:1 relationships?

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  • Computed Column with relationships

    - by Sethery
    I have a table, MapLocation, which has a column and two relationships with tables that have a field that really need to be displayed as a single concatenated value. I was thinking this was a perfect case for a computed column, but not sure how to go about it. MapLocation MaoNo Section _____________________ _____________________ _____________________ MapNoId MapNoId SectionId SectionId MapNumber (int) Section (int) Identifier (nvarchar) LocationName (nvarchar) LocationName = "MapNUmber - SectionNumber - Identifier" ex: 20 - 03 - SW4 How would I write that? I haven't done much with computed columns or concatenating in SQL. Edit: I need an actual computed column that is automatically updated, im looking for the formula. Or is this more of a function/trigger? Its possible, I certainly barely know what I'm doing. The idea is that I dont want to have to do two more server calls and concatenate these values client side.

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  • Problem building relationships between models

    - by Brian Roisentul
    Until now, I've been using acts_as_taggable_on plugin for tagging announcements. That plugin creates the following tables: taggings: relates tags and announcements table(for the tagged item, it has a field called taggable_id, which I rename to "announcement_id" for what I'll explain below). tags: has the tag ids and names. The other day, I discovered that I had no way of getting the announcements tagged with a certain tag, but doing Announcement.tagged_with(tag_name), and I don't want to search by name, but for id. So, as I'm using almost nothing of the functionality in that plugin, I decided to create the models for taggings and tags tables, to accomplish this: Announcement.tags. The models' relationships look as following: class Tagging < ActiveRecord::Base belongs_to :announcement belongs_to :tag end class Tag < ActiveRecord::Base has_many :announcements, :through => :taggings end class Announcement < ActiveRecord::Base has_many :tags, :through => :taggings Why can't I execute the command Announcement.tags? Because when I try, I get undefined method `tags'

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  • Database - Designing an "Events" Table

    - by Alix Axel
    After reading the tips from this great Nettuts+ article I've come up with a table schema that would separate highly volatile data from other tables subjected to heavy reads and at the same time lower the number of tables needed in the whole database schema, however I'm not sure if this is a good idea since it doesn't follow the rules of normalization and I would like to hear your advice, here is the general idea: I've four types of users modeled in a Class Table Inheritance structure, in the main "user" table I store data common to all the users (id, username, password, several flags, ...) along with some TIMESTAMP fields (date_created, date_updated, date_activated, date_lastLogin, ...). To quote the tip #16 from the Nettuts+ article mentioned above: Example 2: You have a “last_login” field in your table. It updates every time a user logs in to the website. But every update on a table causes the query cache for that table to be flushed. You can put that field into another table to keep updates to your users table to a minimum. Now it gets even trickier, I need to keep track of some user statistics like how many unique times a user profile was seen how many unique times a ad from a specific type of user was clicked how many unique times a post from a specific type of user was seen and so on... In my fully normalized database this adds up to about 8 to 10 additional tables, it's not a lot but I would like to keep things simple if I could, so I've come up with the following "events" table: |------|----------------|----------------|--------------|-----------| | ID | TABLE | EVENT | DATE | IP | |------|----------------|----------------|--------------|-----------| | 1 | user | login | 201004190030 | 127.0.0.1 | |------|----------------|----------------|--------------|-----------| | 1 | user | login | 201004190230 | 127.0.0.1 | |------|----------------|----------------|--------------|-----------| | 2 | user | created | 201004190031 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 2 | user | activated | 201004190234 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 2 | user | approved | 201004190930 | 217.0.0.1 | |------|----------------|----------------|--------------|-----------| | 2 | user | login | 201004191200 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | created | 201004191230 | 127.0.0.1 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | impressed | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | clicked | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | clicked | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | clicked | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | clicked | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 15 | user_ads | clicked | 201004191231 | 127.0.0.2 | |------|----------------|----------------|--------------|-----------| | 2 | user | blocked | 201004200319 | 217.0.0.1 | |------|----------------|----------------|--------------|-----------| | 2 | user | deleted | 201004200320 | 217.0.0.1 | |------|----------------|----------------|--------------|-----------| Basically the ID refers to the primary key (id) field in the TABLE table, I believe the rest should be pretty straightforward. One thing that I've come to like in this design is that I can keep track of all the user logins instead of just the last one, and thus generate some interesting metrics with that data. Due to the nature of the events table I also thought of making some optimizations, such as: #9: Since there is only a finite number of tables and a finite (and predetermined) number of events, the TABLE and EVENTS columns could be setup as ENUMs instead of VARCHARs to save some space. #14: Store IPs as UNSIGNED INT with INET_ATON() instead of VARCHARs. Store DATEs as TIMESTAMPs instead of DATETIMEs. Use the ARCHIVE (or the CSV?) engine instead of InnoDB / MyISAM. Overall, each event would only consume 14 bytes which is okay for my traffic I guess. Pros: Ability to store more detailed data (such as logins). No need to design (and code for) almost a dozen additional tables (dates and statistics). Reduces a few columns per table and keeps volatile data separated. Cons: Non-relational (still not as bad as EAV): SELECT * FROM events WHERE id = 2 AND table = 'user' ORDER BY date DESC(); 6 bytes overhead per event (ID, TABLE and EVENT). I'm more inclined to go with this approach since the pros seem to far outweigh the cons, but I'm still a little bit reluctant.. Am I missing something? What are your thoughts on this? Thanks!

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  • Normalizing a table

    - by Alex
    I have a legacy table, which I can't change. The values in it can be modified from legacy application (application also can't be changed). Due to a lot of access to the table from new application (new requirement), I'd like to create a temporary table, which would hopefully speed up the queries. The actual requirement, is to calculate number of business days from X to Y. For example, give me all business days from Jan 1'st 2001 until Dec 24'th 2004. The table is used to mark which days are off, as different companies may have different days off - it isn't just Saturday + Sunday) The temporary table would be created from a .NET program, each time user enters the screen for this query (user may run query multiple times, with different values, table is created once), so I'd like it to be as fast as possible. Approach below runs in under a second, but I only tested it with a small dataset, and still it takes probably close to half a second, which isn't great for UI - even though it's just the overhead for first query. The legacy table looks like this: CREATE TABLE [business_days]( [country_code] [char](3) , [state_code] [varchar](4) , [calendar_year] [int] , [calendar_month] [varchar](31) , [calendar_month2] [varchar](31) , [calendar_month3] [varchar](31) , [calendar_month4] [varchar](31) , [calendar_month5] [varchar](31) , [calendar_month6] [varchar](31) , [calendar_month7] [varchar](31) , [calendar_month8] [varchar](31) , [calendar_month9] [varchar](31) , [calendar_month10] [varchar](31) , [calendar_month11] [varchar](31) , [calendar_month12] [varchar](31) , misc. ) Each month has 31 characters, and any day off (Saturday + Sunday + holiday) is marked with X. Each half day is marked with an 'H'. For example, if a month starts on a Thursday, than it will look like (Thursday+Friday workdays, Saturday+Sunday marked with X): ' XX XX ..' I'd like the new table to look like so: create table #Temp (country varchar(3), state varchar(4), date datetime, hours int) And I'd like to only have rows for days which are off (marked with X or H from previous query) What I ended up doing, so far is this: Create a temporary-intermediate table, that looks like this: create table #Temp_2 (country_code varchar(3), state_code varchar(4), calendar_year int, calendar_month varchar(31), month_code int) To populate it, I have a union which basically unions calendar_month, calendar_month2, calendar_month3, etc. Than I have a loop which loops through all the rows in #Temp_2, after each row is processed, it is removed from #Temp_2. To process the row there is a loop from 1 to 31, and substring(calendar_month, counter, 1) is checked for either X or H, in which case there is an insert into #Temp table. [edit added code] Declare @country_code char(3) Declare @state_code varchar(4) Declare @calendar_year int Declare @calendar_month varchar(31) Declare @month_code int Declare @calendar_date datetime Declare @day_code int WHILE EXISTS(SELECT * From #Temp_2) -- where processed = 0) BEGIN Select Top 1 @country_code = t2.country_code, @state_code = t2.state_code, @calendar_year = t2.calendar_year, @calendar_month = t2.calendar_month, @month_code = t2.month_code From #Temp_2 t2 -- where processed = 0 set @day_code = 1 while @day_code <= 31 begin if substring(@calendar_month, @day_code, 1) = 'X' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 8) end if substring(@calendar_month, @day_code, 1) = 'H' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 4) end set @day_code = @day_code + 1 end delete from #Temp_2 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code --update #Temp_2 set processed = 1 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code END I am not an expert in SQL, so I'd like to get some input on my approach, and maybe even a much better approach suggestion. After having the temp table, I'm planning to do (dates would be coming from a table): select cast(convert(datetime, ('01/31/2012'), 101) -convert(datetime, ('01/17/2012'), 101) as int) - ((select sum(hours) from #Temp where date between convert(datetime, ('01/17/2012'), 101) and convert(datetime, ('01/31/2012'), 101)) / 8) Besides the solution of normalizing the table, the other solution I implemented for now, is a function which does all this logic of getting the business days by scanning the current table. It runs pretty fast, but I'm hesitant to call a function, if I can instead add a simpler query to get result. (I'm currently trying this on MSSQL, but I would need to do same for Sybase ASE and Oracle)

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  • On asp:Table Control how do we create a thead ?

    - by balexandre
    from MSDN article on the subject we can see that we create a TableHeaderRowthat conatins TableHeaderCells. but they add the table header like this: myTable.Row.AddAt(0, headerRow); witch outputs the HTML: <table id="Table1" ... > <tr> <th scope="column" abbr="Col 1 Head">Column 1 Header</th> <th scope="column" abbr="Col 2 Head">Column 2 Header</th> <th scope="column" abbr="Col 3 Head">Column 3 Header</th> </tr> <tr> <td>(0,0)</td> <td>(0,1)</td> <td>(0,2)</td> </tr> ... and it should have <thead> and <tbody> (so it works seamless with tablesorter) :) <table id="Table1" ... > <thead> <tr> <th scope="column" abbr="Col 1 Head">Column 1 Header</th> <th scope="column" abbr="Col 2 Head">Column 2 Header</th> <th scope="column" abbr="Col 3 Head">Column 3 Header</th> </tr> </thead> <tbody> <tr> <td>(0,0)</td> <td>(0,1)</td> <td>(0,2)</td> </tr> ... </tbody> the HTML aspx code is <asp:Table ID="Table1" runat="server" /> How can I output the correct syntax? Just as information, the GridViewcontrol has this builed in as we just need to set teh Accesbility and use the HeaderRow gv.UseAccessibleHeader = true; gv.HeaderRow.TableSection = TableRowSection.TableHeader; gv.HeaderRow.CssClass = "myclass"; but the question is for the Table control.

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