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• Connecting to database on web host in Visual Studio

  - by Anders Svensson

  I have a web site developed locally with a local Sql Server database. I also have a web host that provides one Sql Server database for my site. Now I want to deploy the application, and I would like to be able to manage the remote database from the Server Explorer in Visual Studio. I have the connection string used in the application, which works fine for adding, say, a datasource to a control etc. But I don't know if there's any way to use it to connect the database inside the Server Explorer so that I can add tables etc. I have read that you're supposed to be able to this instead of using the Sql Server Management Studio, but I have'nt read anything about how to connect to the remote database in it. What I have tried so far is this: I have selected Add database in Server Explorer. This brings up first a dialog where I choose Sql Server. And then I get a dialog where I can set Server name (which I tried using the ip address in the connection string below), and Authentication (where I chose Sql Server Authentication, with the user id and password from below). But when I test the connection it fails. Here's the connection string, which works fine when used for datasources in the application (obviously with different user name and password): Any help appreciated!

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• complex web forms and javascript

  - by Casey

  I need to create a few data heavy complicated forms. Currently, the information is being entered into a spread sheet, but the users will need to enter the information into the online form where it will be saved to a database. The problem is that the business users currently using the spread sheet aren't going to want to use the online application if it isn't as easy as entering the information into the spread sheet. This is further complicated in that the information they are entering into the spread sheet is represented by three different DB tables where one "object" is composed of two of the others. I would prefer to not have them have to go through multiple forms. Some of what I have been thinking is: Use of auto complete where possible Hiding/removing form fields dynamically possible wizard style page flow?? I've been googling for other data heavy web forms but can't seem to really find any good examples. I am familiar with jQuery and prototypejs and have also tried googling for frameworks designed for data heavy applications but didn't come up with anything. Any thoughts? Thanks.

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• Understanding MongoDB (and NoSQL in general) and how to make the best use of it

  - by Earlz

  Hello, I am beginning to think that my next project I am wanting to do would work better with a NoSQL solution. The project would either involve a ton of 2-column tables or a ton of dynamic queries with dynamically generated columns in a traditional SQL database. So I feel a NoSQL database would be much cleaner. I'm looking at MongoDB and it looks pretty promising. Anyway, I'm attempting to make sense of it all. Also, I will be using MongoMapper in Ruby. Anyway though, I'm confused as to how to layout things in such a freeform database. I've read http://stackoverflow.com/questions/2170152/nosql-best-practices and the answer there says that normalization is usually bad in a NoSQL DB. So how would be the best way of laying out say a simple blog with users, posts, and comments? My natural thought was to have three collections for each and then link them by a unique ID. But this apparently is wrong? So, what are some of the ways to lay out such a thing? My concern with the answer given in the other question is, what if the author's name changed? You'd have to go through updating a ton of posts and comments. But is this an okay thing to do with NoSQL?

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• Understanding MongoDB(and NoSQL in general) and How to make the best use of it

  - by Earlz

  Hello, I am beginning to think that my next project I am wanting to do would work better with a NoSQL solution. The project would either involve a ton of 2-column tables or a ton of dynamic queries with dynamically generated columns in a traditional SQL database. So I feel a NoSQL database would be much cleaner. I'm looking at MongoDB and it looks pretty promising. Anyway, I'm attempting to make sense of it all. Also, I will be using MongoMapper in Ruby. Anyway though, I'm confused as to how to layout things in such a freeform database. I've read http://stackoverflow.com/questions/2170152/nosql-best-practices and the answer there says that normalization is usually bad in a NoSQL DB. So how would be the best way of laying out say a simple blog with users, posts, and comments? My natural thought was to have 3 collections for each and then link them by a unique ID. But this apparently is wrong? So, what are some of the ways to lay out such a thing? My concern with the answer given in the other question is what if the author's name changed. You'd have to go through updating a ton of posts and comments. But is this an ok thing to do with NoSQL?

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• Find out which row caused the error

  - by Felipe Fiali

  I have a big fat query that's written dynamically to integrate some data. Basically what it does is query some tables, join some other ones, treat some data, and then insert it into a final table. The problem is that there's too much data, and we can't really trust the sources, because there could be some errored or inconsistent data. For example, I've spent almost an hour looking for an error while developing using a customer's database because somewhere in the middle of my big fat query there was an error converting some varchar to datetime. It turned out to be that they had some sales dating '2009-02-29', an out-of-range date. And yes, I know. Why was that stored as varchar? Well, the source database has 3 columns for dates, 'Month', 'Day' and 'Year'. I have no idea why it's like that, but still, it is. But how the hell would I treat that, if the source is not trustable? I can't HANDLE exceptions, I really need that it comes up to another level with the original message, but I wanted to provide some more info, so that the user could at least try to solve it before calling us. So I thought about displaying to the user the row number, or some ID that would at least give him some idea of what record he'd have to correct. That's also a hard job because there will be times when the integration will run up to 80000 records. And in an 80000 records integration, a single dummy error message: 'The conversion of a varchar data type to a datetime data type resulted in an out-of-range datetime value' means nothing at all. So any idea would be appreciated. Oh I'm using SQL Server 2005 with Service Pack 3.

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• CSS Multiple multi-column divs

  - by accelerate

  I have a bunch of items (text, image, mixed content, etc) that I want to display. The user can define what row and what column that item appears in. For example, in row 1, there could be two items/columns, both images. In row two, there could be three items / columns, one with an image, two others as pure text. Oh, and the user may specify the width of any particular column/image/item. I have a solution that uses multiple tables that works. In essence, each row is a new table. This works for the most part. I'm wondering if I can use just divs? Now my CSS foo is lacking, and I tried to copy examples from the web, and I haven't been able to get it working. Right now I have something like this: `[for each row] [for each column] [content] ` But everything is overlapping each other. I've also tried using "position: relative", but things look even more borked. So can divs actually be used for multiple rows and different number of columns?

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• Running RSpec Files From ruby code

  - by Brian D.

  I'm trying to run RSpec tests straight from ruby code. More specifically, I'm running some mysql scripts, loading the rails test environment and then I want to run my rspec tests (which is what I'm having trouble with)... I'm trying to do this with a rake task. Here is my code so far: require"spec" require "spec/rake/spectask" RAILS_ENV = 'test' namespace :run_all_tests do desc "Run all of your tests" puts "Reseting test database..." system "mysql --user=root --password=dev < C:\\Brian\\Work\\Personal\\BrianSite\\database\\BrianSite_test_CreateScript.sql" puts "Filling database tables with test data..." system "mysql --user=root --password=dev < C:\\Brian\\Work\\Personal\\BrianSite\\database\\Fill_Test_Tables.sql" puts "Starting rails test environment..." task :run => :environment do puts "RAILS_ENV is #{RAILS_ENV}" # Run rspec test files here... require "spec/models/blog_spec.rb" end end I thought the require "spec/models/blog_spec.rb" would do it, but the tests aren't running. Anyone know where I'm going wrong? Thanks for any help.

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• Optimzing TSQL code

  - by adopilot

  My job is the maintain one application which heavy use SQL server (MSSQL2005). Until now middle server stores TSQL codes in XML and send dynamic TSQL queries without using stored procs. As I am able change those XML queries I want to migrate most of my queries to stored procs. Question is folowing: Most of my queries have same Where conditions against one table Sample: Select ..... from .... where .... and (a.vrsta_id = @vrsta_id or @vrsta_id = 0) and (a.podvrsta_id = @podvrsta_id or @podvrsta_id = 0) and (a.podgrupa_2 = @podgrupa2_id or @podgrupa2_id = 0) and ( (a.id in (select art_id from osobina_veze where podosobina_id in (select ado from dbo.fn_ado_param_int(@podosobina)) group by art_id having count(art_id)= @podosobina_count )) or ('0' = @podosobina) ) They also have same where conditions on other table. How I should organize my code ? What is proper way ? Should I make table valued function that I will use in all queries or use #Temp tables and simple inner join my query to that each time when proc executing? or use #temp filed by table valued function ? or leave all queries with this large where clause and hope that index is going to do their jobs. or use WITH(statement)

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• How to transform vertical table into horizontal table?

  - by avivo

  Hello, I have one table Person: Id Name 1 Person1 2 Person2 3 Person3 And I have its child table Profile: Id PersonId FieldName Value 1 1 Firstname Alex 2 1 Lastname Balmer 3 1 Email [email protected] 4 1 Phone +1 2 30004000 And I want to get data from these two tables in one row like this: Id Name Firstname Lastname Email Phone 1 Person1 Alex Balmer [email protected] +1 2 30004000 What is the most optimized query to get these vertical (key, value) values in one row like this? Now I have a problem that I done four joins of child table to parent table because I need to get these four fields. Some optimization is for sure possible. I would like to be able to modify this query in easy way when I add new field (key,value). What is the best way to do this? To create some StoreProcedure? I would like to have strongly types in my DB layer (C#) and using LINQ (when programming) so it means when I add some new Key, Value pair in Profile table I would like to do minimal modifications in DB and C# if possible. Actually I am trying to get some best practices in this case.

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• Type or namespace could not be found

  - by Jason Shultz

  I'm using LINQ to SQL to connect my database to my home page. I created my datacontext (named businessModel.dbml) In it I have two tables named Category and Business. In home controller I reference the model and attempt to return to the view the table: var dataContext = new businessModelDataContext(); var business = from b in dataContext.Businesses select b; ViewData["WelcomeMessage"] = "Welcome to Jerome, Arizona!"; ViewData["MottoMessage"] = "Largest Ghost Town in America!"; return View(business); and in the view I have this: <%@ Import Namespace="WelcomeToJerome.Models" %> and <% foreach (business b in (IEnumerable)ViewData.Model) { %> <li><%= b.Title %></li> <% } %> Yet, in the view business is cursed with the red underline and say's that The type or namespace name 'business' could not be found (are you missing a using directive or an assembly reference?) What am I doing wrong? This has had me stumped all afternoon. link to all the code in pastebin: http://pastebin.com/es4RnS2q

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• SQLce DAL Linq to Sql or EntityFramework

  - by bretddog

  Hi, I'm learning databases, using SqlCe, and need business object to database mapping. Currently I try to decide if to use Linq to Sql, or EntityFramework. (I understand a bit L2S, but haven't familiarized with EF yet) The program will only be debeloped and used by myself, so I have good control of the priorities: I don't need to consider potential change of database type or data storage type, as I'm quite certain SQLce will stay sufficient. I DO expect continued development and changes to the data scheme while the program is in active use; change business object properties (Hence database columns), and possibly overall table scheme. So old data must be transported to new scheme. I also want to keep a decent degree of layer separation DAL/BLL, although this may not be necessary, it is good for me to learn these principles. My question is: With these priorities, would I have any benefit by choosing either Linq2Sql vs. EntityFramwork? (and please explain why) Btw, the project involves very simple table scheme with only 4-5 tables and very simple relations. Thanks!

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• symfony doctrine build-sql error

  - by user313571

  I have some big problems with symfony and doctrine at the beginning of a new project. I have created database diagram with mysql workbench, inserted the sql into phpmyadmin and then I've tried symfony doctrine:build-schema to generate the YAML schema. It generates a wrong schema (relations don't have on delete/on update) and after this I've tried symfony doctrine:build --sql and symfony doctrine:insert-sql The insert-sql statement generates error (can't create table ... failing query alter table add constraint ....), so I've decided to take a look over the generated sql and I've found out some differences between the sql generated from mysql workbench (which works perfect, including relations) and the sql generated by doctrine. I'll be short from now: I have to tables, EVENT and FORM and a 1 to n relation (each event may have multiple forms) so the correct constraint (generated with workbench) is ALTER TABLE `form` ADD CONSTRAINT `fk_form_event1` FOREIGN KEY (`event_id`) REFERENCES `event` (`id`) ON DELETE CASCADE ON UPDATE CASCADE; doctrine generated statement is: ALTER TABLE event ADD CONSTRAINT event_id_form_event_id FOREIGN KEY (id) REFERENCES form(event_id); It's totally reversed and I am sure here is the error. What should I do? It's also correct like this?

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• how can I save/keep-in-sync an in-memory graph of objects with the database?

  - by Greg

  Question - What is a good best practice approach for how can I save/keep-in-sync an jn-memory graph of objects with the database? Background: That is say I have the classes Node and Relationship, and the application is building up a graph of related objects using these classes. There might be 1000 nodes with various relationships between them. The application needs to query the structure hence an in-memory approach is good for performance no doubt (e.g. traverse the graph from Node X to find the root parents) The graph does need to be persisted however into a database with tables NODES and RELATIONSHIPS. Therefore what is a good best practice approach for how can I save/keep-in-sync an jn-memory graph of objects with the database? Ideal requirements would include: build up changes in-memory and then 'save' afterwards (mandatory) when saving, apply updates to database in correct order to avoid hitting any database constraints (mandatory) keep persistence mechanism separate from model, for ease in changing persistence layer if needed, e.g. don't just wrap an ADO.net DataRow in the Node and Relationship classes (desirable) mechanism for doing optimistic locking (desirable) Or is the overhead of all this for a smallish application just not worth it and I should just hit the database each time for everything? (assuming the response times were acceptable) [would still like to avoid if not too much extra overhead to remain somewhat scalable re performance]

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• Using JSF, PrimeFaces and JPA: Create Basic WebApp without using Generated CRUD Classes, Forms, etc

  - by user2774489

  I am trying to build a basic CRUD application with NetBeans 7.4, JSF, PrimeFaces and JPA using MySQL. I have successfully done this by using the NetBeans wizards. I want to do this from scratch, no wizards. There seems to be a lack of support for the combo of JSF, PrimeFaces and JPA. When I say "lack", I mean a full example (I might be asking too much), without using the CRUD auto-gen templates/classes AND shows actual queries coded and passed to the datatables(primefaces). YouTube is full of non-English speaking examples using Hibernate (not JPA) and other examples that show flashy GUI's with no code. So far I understand you need an @Entity class (provides the physical build of the tables), a Controller (serializable) and the .xhtml web page to show the datatable.. what else? Also, I'm not seeing any posts or examples where queries are using with JPA/JSF and how they are tied together (in one place). I need to connect the dots here so that I can leverage JSF/JPA to create simple queries to populate my PF DataTables. I've read the blogs and I've googled the intranets until I'm blue in the face. Sending me a list of URL's to read to learn about each product is something I've already done. I get what they do independently, but am looking for the "How do they all connect" answer with maybe some basic code examples!! :)

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• Web Shop Schema - Document Db

  - by Maxem

  I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

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• How can I map stored procedure result into a custom class with linq-to-sql?

  - by Remnant

  I have a stored procedure that returns a result set (4 columns x n Rows). The data is based on multiple tables within my database and provides a summary for each department within a corporate. Here is sample: usp_GetDepartmentSummary DeptName EmployeeCount Male Female HR 12 5 7 etc... I am using linq-to-sql to retrieve data from my database (nb - have to use sproc as it is something I have inherited). I would like to call the above sproc and map into a department class: public class Department { public string DeptName {get; set;} public int EmployeeCount {get; set;} public int MaleCount {get; set;} public int FemaleCount {get; set;} } In VS2008, I can drag and drop my sproc onto the methods pane of the linq-to-sql designer. When I examine the designer.cs the return type for this sproc is defined as: ISingleResult<usp_GetDepartmentSummaryResult> What I would like to do is amend this somehow so that it returns a Department type so that I can pass the results of the sproc as a strongly typed view: <% foreach (var dept in Model) { %> <ul> <li class="deptname"><%= dept.DeptName %></li> <li class="deptname"><%= dept.EmployeeCount %></li> etc... Any ideas how to achieve this? NB - I have tried amending the designer.cs and dbml xml file directly but with limited success. I admit to being a little out of my depth when it comes to updating those files directly and I am not sure it is best practice? Would be good to get some diretion. Thanks much

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• UITableView with Custom Cell only loads one row of data at a time

  - by Anton

  For my table, I've created a custom cell that has two labels. I also have two arrays with data, that I use to respectively assign each label in the cell. My problem, is that when the table is viewed, only the first row has data, and the rest of the data "sorta" loads when I start scrolling down. By "sorta", only the first row will load at a time. The only time I get to see all the data, is when I scroll to the bottom, then scroll up again. I've used the cellForRowAtIndexPath method to load the data into my cell. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CustomCellIdentifier = @"CustomCellIdentifier"; CustomCell *cell = (CustomCell *)[tableView dequeueReusableCellWithIdentifier:CustomCellIdentifier]; if (cell == nil) { NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:self options:nil]; for (id oneObject in nib) if ([oneObject isKindOfClass:[CustomCell class]]) cell = (CustomCell *)oneObject; } NSUInteger row = [indexPath row]; //I have two tables to fill up, hence the tag if statement if ([tableView tag] == 0) { cell.arriveTimeLabel.text = [homeBoundTimes objectAtIndex:row]; cell.departTimeLabel.text = [homeBoundTimes objectAtIndex:row]; } else if ([tableView tag] == 1) { cell.arriveTimeLabel.text = [workBoundTimes objectAtIndex:row]; cell.departTimeLabel.text = [workBoundTimes objectAtIndex:row]; } return cell; } Is it possible that its only getting called when the top cell is being called?

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• Use Django ORM as standalone [closed]

  - by KeyboardInterrupt

  Possible Duplicates: Use only some parts of Django? Using only the DB part of Django I want to use the Django ORM as standalone. Despite an hour of searching Google, I'm still left with several questions: Does it require me to set up my Python project with a setting.py, /myApp/ directory, and modules.py file? Can I create a new models.py and run syncdb to have it automatically setup the tables and relationships or can I only use models from existing Django projects? There seems to be a lot of questions regarding PYTHONPATH. If you're not calling existing models is this needed? I guess the easiest thing would be for someone to just post a basic template or walkthrough of the process, clarifying the organization of the files e.g.: db/ __init__.py settings.py myScript.py orm/ __init__.py models.py And the basic essentials: # settings.py from django.conf import settings settings.configure( DATABASE_ENGINE = "postgresql_psycopg2", DATABASE_HOST = "localhost", DATABASE_NAME = "dbName", DATABASE_USER = "user", DATABASE_PASSWORD = "pass", DATABASE_PORT = "5432" ) # orm/models.py # ... # myScript.py # import models.. And whether you need to run something like: django-admin.py inspectdb ... (Oh, I'm running Windows if that changes anything regarding command-line arguments.).

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• SQL Server performance issue.

  - by Jit

  Hi Friends, I have been trying to analyze performance issue with SQL Server 2005. We have 30 jobs, one for each databases (30 databases, one per each client). The jobs run at early morning at an interval of 5 minutes. When I run the job individually for testing, for most of the databases it finishes in 7 to 9 minutes. But when these jobs run at early morning, I see few jobs taking 2 to 3 hours to finish and the same takes few minutes as mentioned above if ran independently. We dont have any other job scheduled during that time, other than these 30 jobs. If we restart the server then for 2 or so days all the jobs finishes in few minutes, but over the period of time (from 3rd day suddenly), few jobs start taking hours to finish. What could be the possible reason of performance degradation over the period of time? I verified all the SPs and we uses temp tables and I made sure none of the temp table is left without dropping at the end of SP. Let me know what are the possible reasons for such behavior. Appreciate your time and help. Thanks

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• Need some help with a MySQL subquery count

  - by Ferdy

  I'm running into my own limits of MySQL query skills, so I hope some SQL guru can help out on this one. The situation is as follow: I have images that can be tagged. As you might expect this is stored in three tables: Image Tag Tag_map (maps images to tags) I have a SQL query that calculates the related tags based on a tag id. The query basically checks what other tags were used for images for images using that tag. Example: Image1 tagged as "Bear" Image2 tagged as "Bear" and "Canada" If I throw "Bear" (or its tag id) at the query, it will return "Canada". This works fine. Here's the query: SELECT tag.name, tag.id, COUNT(tag_map.id) as cnt FROM tag_map,tag WHERE tag_map.tag_id = tag.id AND tag.id != '185' AND tag_map.image_id IN (SELECT tag_map.image_id FROM tag_map INNER JOIN tag ON tag_map.tag_id = tag.id WHERE tag.id = '185') GROUP BY tag_map.id LIMIT 0,100 The part I'm stuck with is the count. For each related tag returned, I want to know how many images are in that tag. Currently it always returns 1, even if there are for example 3. I've tried counting different columns all resulting in the same output, so I guess there is a flaw in my thinking.

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• How can I properly handle 404s in ASP.NET MVC?

  - by Brian

  I am just getting started on ASP.NET MVC so bear with me. I've searched around this site and various others and have seen a few implementations of this. EDIT: I forgot to mention I am using RC2 Using URL Routing: routes.MapRoute( "Error", "{*url}", new { controller = "Errors", action = "NotFound" } //404s ); The above seems to take care of requests like this (assuming default route tables setup by initial MVC project): "/blah/blah/blah/blah" Overriding HandleUnknownAction() in the controller itself: //404s - handle here (bad action requested protected override void HandleUnknownAction(string actionName) { ViewData["actionName"] = actionName; View("NotFound").ExecuteResult(this.ControllerContext); } However the previous strategies do not handle a request to a Bad/Unknown controller. For example, I do not have a "/IDoNotExist", if I request this I get the generic 404 page from the web server and not my 404 if I use routing + override. So finally, my question is: Is there any way to catch this type of request using a route or something else in the MVC framework itself? OR should I just default to using Web.Config customErrors as my 404 handler and forget all this? I assume if I go with customErrors I'll have to store the generic 404 page outside of /Views due to the Web.Config restrictions on direct access. Anyway any best practices or guidance is appreciated.

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• Which Table Should be Master and Child in Database Design

  - by Jason

  I am quickly learning the ins and outs of database design (something that, as of a week ago, was new to me), but I am running across some questions that don't seem immediately obvious, so I was hoping to get some clarification. The question I have right is about foreign keys. As part of my design, I have a Company table. Originally, I had included address information directly within the table, but, as I was hoping to achieve 3NF, I broke out the address information into its own table, Address. In order to maintain data integrity, I created a row in Company called "addressId" as an INT and the Address table has a corresponding addressId as its primary key. What I'm a little bit confused about (or what I want to make sure I'm doing correctly) is determining which table should be the master (referenced) table and which should be the child (referencing) table. When I originally set this up, I made the Address table the master and the Company the child. However, I now believe this is wrong due to the fact that there should be only one address per Company and, if a Company row is deleted, I would want the corresponding Address to be removed as well (CASCADE deletion). I may be approaching this completely wrong, so I would appreciate any good rules of thumb on how to best think about the relationship between tables when using foreign keys. Thanks!

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• EF 6 Code First Many to many With Payload and self referencing many to many

  - by lesley86

  I Have the problem where i have a many to many relationship and on one of the tables there will be a self referencing many to many. So basically a school have zero or many groups and many groups can have 0 or many schools. The groups table will contain a parent child many to many with itself because a group can be a child of another group or it can have no children and that child can have a child, one child can also have many parents or a entity can have no parents. I created a mapping table with Payload to solvethe first many to many problem. code snippet public class School { public virtual ICollection<SchoolGroupMap> SchoolGroupMaps } public class SchoolGroup { public virtual ICollection<SchoolGroupMap> SchoolGroupMaps } public class SchoolGroupMap { public virtual School School public virtual SchoolGroup SchoolGroup } i Then tried modifying the code the following way for the the self referencing many to many public class SchoolGroup { public virtual ICollection<SchoolGroupMap> SchoolGroupMaps public virtual ICollection<SchoolGroup> Parents public virtual ICollection<SchoolGroup> Children } I changed the context with has many and an auto mapping table (forgive me i have been trying so many things today i do not have the exact code). I received an error the properties on the classes must match. Can anyone help please. I want to do create navigation properties on the self referencing many to many. Also a seed example would be appreciated regards

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• Erlang ODBC parameter query with null parameters

  - by Schlomer

  Is it possible to pass null values to parameter queries? For example Sql = "insert into TableX values (?,?)". Params = [{sql_integer, [Val1]}, {sql_float, [Val2]}]. % Val2 may be a float, or it may be the atom, undefined odbc:param_query(OdbcRef, Sql, Params). Now, of course odbc:param_query/3 is going to complain if Val2 is undefined when trying to match to a sql_float, but my question is... Is it possible to use a parameterized query, such as: Sql = "insert into TableY values (?,?,?,?,?,?,?,?,?)". with any null parameters? I have a use case where I am dumping a large number of real-time data into a database by either inserting or updating. Some of the tables I am updating have a dozen or so nullable fields, and I do not have a guarantee that all of the data will be there. Concatenating a SQL together for each query, checking for null values seems complex, and the wrong way to do it. Having a parameterized query for each permutation is simply not an option. Any thoughts or ideas would be fantastic! Thank you!

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• Core Data: Overkill for simple, static UITableView-based iPhone App?

  - by David Foster

  Hello! I have a rather simple iPhone app consisting of numerous views containing a single, grouped table view. These views are held together in navigation controllers which are grouped in a tab bar. Simple stuff. My table views do little more than list text (like "Dog", "Cat" and "Weasel") and this data is being served from a collection of plists. It's perhaps worth mentioning too that these tables are 'static' in the sense that their data is pre-determined and will only ever be amended—and if so, very rarely indeed—by the developer (in this case, moi). This rudimentary approach has reached its limits though, and I think I'm going to need something a bit more relational. I have worked a tad with Core Data in the past, but only with apps whose data is determined by user input. I have four closely related questions: Is Core Data overkill for an app consisting mainly of a selection of simple table views? Do you recommend using Core Data to manage data which is predetermine and extremely unlikely to ever change? Can one lock Core Data down so that its data can't change, thereby relinquishing my responsibility as the developer to handle the editing and saving of the managed object context? How do I go about giving Core Data my predetermined data, and in a format I know that it can work with? Thanks a bunch guys.

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