sql - Multiple many to many relationships between same tables or one n:m relationship with identifying attribute? -

sql - Multiple many to many relationships between same tables or one n:m relationship with identifying attribute? -

Currently I have several n: m links between the two tables:

  - & gt; Favorites (user_id, post_id) & lt; - Post users - & gt; Follow (user_id, post_id) & lt; - Mail    Is there a feature to join in 2 or just one, which is a symbol of the type of joining, something like this:  
  user - & gt; User file (user_id, post_id, type (VALUES = "favorite, follow") & lt; - mail    In my application I do not have this at all, but I think that You think that there is a "right" answer. I think   
 
  strong> dependent . If you use a single table with the "Relationship Type" column and want to remove only one kind of relationship - then just enter it Nandita - then you will need to apply every query to that table, for such type of people whom you  not  want to filter, there is a rule that can be for slow queries. -Keys do not properly index the "Relationship Type" column. Also, it does so that future developers should always know what type of filter they want to filter or they want to filter. It is possible to get back the relationship data that is expected to come back. Two different tables are easy to understand. For example, for me, what is known to EXPEC is a comparison of the "Users_Posts" table In the "Favorites" table, you can convey the difference in different tables faster. On the other hand, if you often need to select  both  type of relationship in a set, then it is easy to put them in a table because you can add data to single tables on a table with two tables There is no need to worry about. What if there are 10,000 different possible connection types? Do you want 10,000 different tables, or would you like the same table? Most people prefer the same table in that case.  
 So I think it depends on many factors, such as expected usage, size etc. "Right" answer is more than an art than science.   

 


  







03:22

















Get link





Facebook





X





Pinterest





Email





Other Apps




Comments





Post a Comment







Popular Posts









r - Plot correlation matrix into a graph -



    I have a matrix with some correlation values. I now want to plot in that graphic which is more like this or Looks less:         Library (Latis) # Horizontal and vertical axis information please take- c (div class = "post-text" itemprop = "text">  "214", "215", "216", "224", "211", "212", "213", "223", "226", "225") & lt; - Paste ("DM1- ", Hor, sep =" ") # counterfeit co Relation matrix narokol & lt; (I 1: nrowcol) for core [i] - length (var) core & lt; - matrix (runif (nrowcol * nrowcol, min = 0.4), nrow = nrowcol, ncol = nrowcol (Color, "blue", "yellow"), space = "RGB"), levelplates (core, main = "dimnames = list (hor, ver)), I] = 1 # plot rgb. Stage 12-14 array correlation matrix ") Xlab =" ", ylab =" ", col.regions = rgb.palette (120), cut = 100, at = seq (0,1,0.01)) ...






asp.net - RegisterUser: CreateUserWizardStep -



    When using CreateUserWizardStep to register a new user I'm having a problem.   Help me solve this problem.I have tried to configure in the web. Provider tag for configuration    & lt; Required question and answer = "wrong" & gt;    Although it still does not work ... I'm using the MySQL database    RegisterUser :. An IEditableTextControl is not included with the CreateUserWizardStep.ContentTemplate ID question for the security question, it is necessary that your membership provider needs a question and answer.   Source error:   An unrestricted exception occurred during the execution of existing web requests. Information about the origin and location of the exception can be identified using the exception stack trace below.   Stack trace:.   [HttpException (0x80004005): RegisterUser: CreateUserWizardStep.ContentTemplate does not include questions IEditableTextControl security question with the ID, it is necessary to require a question and answer your subscri...






Integrate flash games in android app? -



    3 is a flash game that I want to integrate into a menu / list in the Android app. So when the user selects the game from the list, the game starts with the help of the Android Flash Player.   Is it better or better with webwave?   Is there any good tutorial?   Thank you! Adobe Flash provides a good way: you can create a breeze for the Android app.    Use this to create your menu and compile three games in your air app.   Here are some tutorial links about how to publish AiI for Android applications and:   PART1: AIR for Android, PART2:   Publication for Android apps: Ai:   I do not believe that the Android Flash Player can be launched with a single intention so far, so using Java Android will not solve it (now ) And   and a third approach Whatever you mentioned, it should work - using the webwave.








Powered by Blogger