Search Results

Search found 1148 results on 46 pages for 'backbone relational'.

Page 15/46 | < Previous Page | 11 12 13 14 15 16 17 18 19 20 21 22  | Next Page >

  • Accessing two sides of a user-user relationship in rails

    - by Lowgain
    Basically, I have a users model in my rails app, and a fanship model, to facilitate the ability for users to become 'fans' of each other. In my user model, I have: has_many :fanships has_many :fanofs, :through => :fanships In my fanship model, I have: belongs_to :user belongs_to :fanof, :class_name => "User", :foreign_key => "fanof_id" My fanship table basically consists of :id, :user_id and :fanof_id. This all works fine, and I can see what users a specific user is a fan of like: <% @user.fanofs.each do |fan| %> #things <% end %> My question is, how can I get a list of the users that are a fan of this specific user? I'd like it if I could just have something like @user.fans, but if that isn't possible what is the most efficient way of going about this? Thanks!

    Read the article

  • Dynamic class_name for has_many relations

    - by vooD
    I'm trying to make has_many relation with dynamic class_name attribute class Category < ActiveRecord::Base has_many :ads, :class_name => ( lambda { return self.item_type } ) end or class Category < ActiveRecord::Base has_many :ads, :class_name => self.item_type end But i got errors: can't convert Proc into String or undefined method `item_type' for #<Class:0xb62c6c88> Thank you for any help!

    Read the article

  • mysql codeigniter active record m:m deletion

    - by sea_1987
    Hi There, I have a table 2 tables that have a m:m relationship, what I can wanting is that when I delete a row from one of the tables I want the row in the joining table to be deleted as well, my sql is as follow, Table 1 CREATE TABLE IF NOT EXISTS `job_feed` ( `id` int(11) NOT NULL AUTO_INCREMENT, `body` text NOT NULL, `date_posted` int(10) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; Table 2 CREATE TABLE IF NOT EXISTS `job_feed_has_employer_details` ( `job_feed_id` int(11) NOT NULL, `employer_details_id` int(11) NOT NULL, PRIMARY KEY (`job_feed_id`,`employer_details_id`), KEY `fk_job_feed_has_employer_details_job_feed1` (`job_feed_id`), KEY `fk_job_feed_has_employer_details_employer_details1` (`employer_details_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; So what I am wanting to do is, if the a row is deleted from table1 and has an id of 1 I want the row in table to that also has that idea as part of the relationship also. I want to do this in keeping with codeigniters active record class I currently have this, public function deleteJobFeed($feed_id) { $this->db->where('id', $feed_id) ->delete('job_feed'); return $feed_id; }

    Read the article

  • NHibernate / ORM - Child Update over Web Service

    - by tyndall
    What is the correct way to UPDATE a child object with NHibernate but not have to "awake" the parent object. Lets say you would like to try to avoid this because the parent object is large or expensive to initiate. Lets assume classes are called Author(parent) and Book(child). (still, trying to avoid instantiating Author) Book comes back over a web service as XML. It gets deserialized back into a CLR object. Book has an AuthorId property which allows this to happen. But it also has a Author property. Problem, comes when you try to SaveOrUpdate() Book and the author_id in the database gets wiped out because the Author was null when the object gets deserialized. This seems like this would be a common problem. What is the workaround? Also, if you instantiate the Author and it has a Books property. The book you are trying to update is already one of these books (List<Book>). We have also run into the "a different object with the same identifier value was already associated with the session" problems. What is the standard process to update a child over a web service?

    Read the article

  • sql query for student schema

    - by user1214208
    I tried solving the below question.I just want to make sure if I am correct. student(student-name, street, city) offering(department, number, section, time, population) titles(department, number, title) enrollment(student-name, department, number, section) If I need to find The department, number, section, title, and population for every course section The SQL query I tried is : select a.department, a.number, a.section,b.title,population as "students" from offering a ,titles b ,enrollment c,student d where a.department=b.department and a.number=b.number and a.department=c.department and a.number=c.number and a.section=c.section group by a.section Please let me know if I am correct. Thank you for your time and patience.

    Read the article

  • which sql query is more efficient: select count(*) or select ... where key>value?

    - by davka
    I need to periodically update a local cache with new additions to some DB table. The table rows contain an auto-increment sequential number (SN) field. The cache keeps this number too, so basically I just need to fetch all rows with SN larger than the highest I already have. SELECT * FROM table where SN > <max_cached_SN> However, the majority of the attempts will bring no data (I just need to make sure that I have an absolutely up-to-date local copy). So I wander if this will be more efficient: count = SELECT count(*) from table; if (count > <cache_size>) // fetch new rows as above I suppose that selecting by an indexed numeric field is quite efficient, so I wander whether using count has benefit. On the other hand, this test/update will be done quite frequently and by many clients, so there is a motivation to optimize it.

    Read the article

  • How to Design a Relational Database; PASS Precon Swag and it’s “Symbolism”

    - by drsql
    Update! 10 more books added to the cadre from my friends at Red-Gate. With less than a week to go, I am starting to pack up for Charlotte and PASS 2013. I love that it is in Charlotte this year so I can drive and bring along some goodies to give away. Books and toys mostly, a variety of which were chosen rather specifically for some manner of symbolism with a tie in to database design for the most part. (Okay, symbolism is perhaps a bit of a stretch, but I have tied everything, even the goofy stuff,...(read more)

    Read the article

  • SQL SERVER – What is the Maximum Relational Database Size Supported by Single Instance?

    - by Pinal Dave
    I often get asked following question? “How much data SQL Server can handle?” Every single time when I get this question – I ask back following question - “How much data your storage system can handle?” The reason I ask this question back is because in reality for enterprise systems the limitation of storage is no more an issue. The Matter of the fact most of the database is now a days limited by the size of the storage system. SQL Server is enterprise system and it is very mature product. Even though if you still want to know what is the actual limit here is the answer. SQL Server 2008R2, 2012 and 2014 have maximum capacity of 524 PB (Petabyte) in the Enterprise, BI and Standard edition. SQL Server Express has a limitation of 10 GB due to its nature. I guess, now when you look at my question it will make sense that it is all depending on the size of your storage system. I personally believe at this point of time 524 PB is quite a huge data, but we never know after 10 years when we read this blog post, we all may think what was I thinking actually. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • What are the advantages of storing xml in a relational database?

    - by Chris
    I was poking around the AdventureWorks database today and I noticed that a number of tables (HumanResources.JobCandidate and Sales.Individual for example) have a column which is storing xml data. What I would to know is, what is the advantage of storing basically a database table row's worth of data in another table's column? Doesn't this make it difficult to query off of this information? Or is the assumption that the data won't need to be queried and just needs to be stored?

    Read the article

  • What are the advantages of storing xml in a relational database?

    - by Chris
    I was poking around the AdventureWorks database today and I noticed that a number of tables (HumanResources.JobCandidate and Sales.Individual for example) have a column which is storing xml data. What I would to know is, what is the advantage of storing basically a database table row's worth of data in another table's column? Doesn't this make it difficult to query off of this information? Or is the assumption that the data won't need to be queried and just needs to be stored?

    Read the article

  • What are some ways people deploy relational database changes using Node.js? [closed]

    - by JamesEggers
    I've been diving more and more into Node.js and hosting services like Heroku and Nodejitsu recently and have been trying to figure out how to best deploy database changes for postgres or mysql. There are a few migration projects under npm that I can see; however, all seem to be really buggy or just not work. I currently manage the Monarch migration project on npm, but it's currently buggy itself and my experiences developing such utilities are in other, more procedural, languages. So what do people use to deploy changes to their databases on these environments? What has worked for people? I'm looking for a better understanding of what the current situation/process looks like.

    Read the article

  • Is it justified to use project-wide unique function and variable names to help future refactoring?

    - by kahoon
    Refactoring tools (like ReSharper) often can't be sure whether to rename a given identifier when, for example refactoring a JavaScript function. I guess this is a consequence of JavaScript's dynamic nature. ReSharper solves this problem by offering to rename reasonable lexical matches too. The developer can opt out of renaming certain functions, if he finds that the lexical match is purely accidental. This means that the developer has to approve every instance that will be affected by the renaming. For example let's consider we have two Backbone classes which are used completely independently from each other in our application: var Header = Backbone.View.extend({ close: function() {...} }) var Dialog = Backbone.View.extend({ close: function() {...} }) If you try to rename Dialog's close method to for example closeAndNotify, then ReSharper will offer to rename all occurences of Header's close method just because they are the same lexically prior to the renaming. To avoid this problem, please consider this: var Header = Backbone.View.extend({ closeHeader: function() {...} }) var Dialog = Backbone.View.extend({ closeDialog: function() {...} }) Now you can rename closeDialog unambiguously - given that you have no other classes having a method with the same name. Is it worth it to name my functions this way to help future refactoring?

    Read the article

  • Designing a user-defined list to be stored in a relational database - Should I include user index?

    - by Zaemz
    By index, I mean, as the user creates the list, each item receives an integer index for its place in that particular list. Since there will be a table of ListItems, I'd prefer to avoid using the name "Index" for the field. Then I was thinking - should I even include the list index in the database? I figured I would because the list would be created in the same fashion every time, then. Or I could order the list for the user based on its actual primary key, since the list items are created in succession anyway... What should I do?

    Read the article

  • Big Data – Evolution of Big Data – Day 3 of 21

    - by Pinal Dave
    In yesterday’s blog post we answered what is the Big Data. Today we will understand why and how the evolution of Big Data has happened. Though the answer is very simple, I would like to tell it in the form of a history lesson. Data in Flat File In earlier days data was stored in the flat file and there was no structure in the flat file.  If any data has to be retrieved from the flat file it was a project by itself. There was no possibility of retrieving the data efficiently and data integrity has been just a term discussed without any modeling or structure around. Database residing in the flat file had more issues than we would like to discuss in today’s world. It was more like a nightmare when there was any data processing involved in the application. Though, applications developed at that time were also not that advanced the need of the data was always there and there was always need of proper data management. Edgar F Codd and 12 Rules Edgar Frank Codd was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases. He presented 12 rules for the Relational Database and suddenly the chaotic world of the database seems to see discipline in the rules. Relational Database was a promising land for all the unstructured database users. Relational Database brought into the relationship between data as well improved the performance of the data retrieval. Database world had immediately seen a major transformation and every single vendors and database users suddenly started to adopt the relational database models. Relational Database Management Systems Since Edgar F Codd proposed 12 rules for the RBDMS there were many different vendors who started them to build applications and tools to support the relationship between database. This was indeed a learning curve for many of the developer who had never worked before with the modeling of the database. However, as time passed by pretty much everybody accepted the relationship of the database and started to evolve product which performs its best with the boundaries of the RDBMS concepts. This was the best era for the databases and it gave the world extreme experts as well as some of the best products. The Entity Relationship model was also evolved at the same time. In software engineering, an Entity–relationship model (ER model) is a data model for describing a database in an abstract way. Enormous Data Growth Well, everything was going fine with the RDBMS in the database world. As there were no major challenges the adoption of the RDBMS applications and tools was pretty much universal. There was a race at times to make the developer’s life much easier with the RDBMS management tools. Due to the extreme popularity and easy to use system pretty much every data was stored in the RDBMS system. New age applications were built and social media took the world by the storm. Every organizations was feeling pressure to provide the best experience for their users based the data they had with them. While this was all going on at the same time data was growing pretty much every organization and application. Data Warehousing The enormous data growth now presented a big challenge for the organizations who wanted to build intelligent systems based on the data and provide near real time superior user experience to their customers. Various organizations immediately start building data warehousing solutions where the data was stored and processed. The trend of the business intelligence becomes the need of everyday. Data was received from the transaction system and overnight was processed to build intelligent reports from it. Though this is a great solution it has its own set of challenges. The relational database model and data warehousing concepts are all built with keeping traditional relational database modeling in the mind and it still has many challenges when unstructured data was present. Interesting Challenge Every organization had expertise to manage structured data but the world had already changed to unstructured data. There was intelligence in the videos, photos, SMS, text, social media messages and various other data sources. All of these needed to now bring to a single platform and build a uniform system which does what businesses need. The way we do business has also been changed. There was a time when user only got the features what technology supported, however, now users ask for the feature and technology is built to support the same. The need of the real time intelligence from the fast paced data flow is now becoming a necessity. Large amount (Volume) of difference (Variety) of high speed data (Velocity) is the properties of the data. The traditional database system has limits to resolve the challenges this new kind of the data presents. Hence the need of the Big Data Science. We need innovation in how we handle and manage data. We need creative ways to capture data and present to users. Big Data is Reality! Tomorrow In tomorrow’s blog post we will try to answer discuss Basics of Big Data Architecture. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

    Read the article

  • Best practices for combining Lucene.NET and a relational database?

    - by FlySwat
    I'm working on a project where I will have a LOT of data, and it will be searchable by several forms that are very efficiently expressed as SQL Queries, but it also needs to be searched via natural language processing. My plan is to build an index using Lucene for this form of search. My question is that if I do this, and perform a search, Lucene will then return the ID's of matching documents in the index, I then have to lookup these entities from the relational database. This could be done in two ways (That I can think of so far): N amount of queries (Horrible) Pass all the ID's to a stored procedure at once (Perhaps as a comma delimited parameter). This has the downside of being limited to the max parameter size, and the slow performance of a UDF to split the string into a temporary table. I'm almost tempted to mirror everything into lucenes index, so that I can periodicly generate the index from the backing store, but only need to access it for the frontend. Advice?

    Read the article

  • Is it possible to listen to relational database update?

    - by Morgan Cheng
    Is it possible to listen to relation database update? For example, my web app want to send data update to client through Comet technology. I can have the program to poll the database periodically, but that would not be performant and scalable. If app can hood to a "event handler" of database, then app can get notification every time given database table data is updated. This sounds more promising, but I didn't find any concrete example for it. This is listener pattern. Does common relational database support such feature?

    Read the article

  • mySQL & Relational databases: How to handle sharding/splitting on application level?

    - by Industrial
    Hi everybody, I have thought a bit about sharding tables, since partitioning cannot be done with foreign keys in a mySQL table. Maybe there's an option to switch to a different relational database that features both, but I don't see that as an option right now. So, the sharding idea seems like a pretty decent thing. But, what's a good approach to do this on a application level? I am guessing that a take-off point would be to prefix tables with a max value for the primary key in each table. Something like products_4000000 , products_8000000 and products_12000000. Then the application would have to check with a simple if-statement the size of the id (PK) that will be requested is smaller then four, eight or twelve million before doing any actual database calls. So, is this a step in the right direction or are we doing something really stupid?

    Read the article

  • What's the best way to store custom objects in relational database?

    - by user342610
    I have my objects with their properties. Objects could change their structure: properties may be added/removed/changed. Objects could be absolutely dropped. So object's metadata (description, classes, call them like you want :) )could be changed. The database should store objects schemas and instances of these objects. What's the best way to organise a relational database structure to store data mentioned above? Currently I see only two ways: 1) Store objects schemas in a few tables: schema general data,schema properties, possible properties types. Store instances in their tables: instance general data, a few tables - per each type from possible properties types table to store instance properties data. And so on. 2) store objects schemas like in p1 but store instances like XML files in one table: one table for general instance info and one table with instance XML. please, don't ask why/for what I need this. Just need to store custom objects and DB should work fast :)

    Read the article

< Previous Page | 11 12 13 14 15 16 17 18 19 20 21 22  | Next Page >