Search Results

Search found 41135 results on 1646 pages for 'non relational database'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 188/1646 | < Previous Page | 184 185 186 187 188 189 190 191 192 193 194 195  | Next Page >

  • Inlining an array of non-default constructible objects in a C++ class

    - by porgarmingduod
    C++ doesn't allow a class containing an array of items that are not default constructible: class Gordian { public: int member; Gordian(int must_have_variable) : member(must_have_variable) {} }; class Knot { Gordian* pointer_array[8]; // Sure, this works. Gordian inlined_array[8]; // Won't compile. Can't be initialized. }; As even beginner C++ users know, the language guarantees that all members are initialized when constructing a class. And it doesn't trust the user to initialize everything in the constructor - one has to provide valid arguments to the constructors of all members before the body of the constructor even starts. Generally, that's a great idea as far as I'm concerned, but I've come across a situation where it would be a lot easier if I could actually have an array of non-default constructible objects. The obvious solution: Have an array of pointers to the objects. This is not optimal in my case, as I am using shared memory. It would force me to do extra allocation from an already contended resource (that is, the shared memory). The entire reason I want to have the array inlined in the object is to reduce the number of allocations. This is a situation where I would be willing to use a hack, even an ugly one, provided it works. One possible hack I am thinking about would be: class Knot { public: struct dummy { char padding[sizeof(Gordian)]; }; dummy inlined_array[8]; Gordian* get(int index) { return reinterpret_cast<Gordian*>(&inlined_array[index]); } Knot() { for (int x = 0; x != 8; x++) { new (get(x)) Gordian(x*x); } } }; Sure, it compiles, but I'm not exactly an experienced C++ programmer. That is, I couldn't possibly trust my hacks less. So, the questions: 1) Does the hack I came up with seem workable? What are the issues? (I'm mainly concerned with C++0x on newer versions of GCC). 2) Is there a better way to inline an array of non-default constructible objects in a class?

    Read the article

  • rais belong_to which class to choose

    - by Small Wolf
    There is a model relation like this. class A belongs_to :ref_config,:class_name => 'User' end My question is : the A has a attribute named flag, now i want to create a function like this: if flag == 1, I want the class A like this belongs_to :ref_config,:class_name => 'Department and if flag == 2, i want the class A like this belongs_to :ref_config,:class_name => 'User' How can I implement the function Thank you!

    Read the article

  • Junit before class ( non static )

    - by Roman
    Are there any best practices to get Junit execute a function once in a test file , and it should also not be static. like @BeforeClass on non static function? Here is an ugly solution : @Before void init(){ if (init.get() == false){ init.set(true); // do once block } } well this is something i dont want to do , and i am looking for an integrated junit solution.

    Read the article

  • Update database schema with hibernate

    - by blow
    Hi all, with <property name="hibernate.hbm2ddl.auto">update</property> i can create my database schema, it automatically add properties, constraint, key etc... But what about UPDATE the database schema? If i remove some property from my entities, hibernate doesn't remove it, or if i change some constraint, hibernate doesn't touch constraint already created... So, there is a way to make hibernate really update the database schema? Thanks.

    Read the article

  • 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

  • Rspec > testing database views

    - by Sean McCleary
    How can database views be tested in Rspec? Every scenario is wrapped in a transaction and the data does not look like it is being persisted to the database (MySQL in my case). My view returns with an empty result set because none of the records are being persisted in the transaction. I am validating that the records are not being stored by setting a debug point in my spec and checking my data with a database client while the spec is being debugged. The only way I can think to have my view work would be if I could commit the transaction before the end of the scenario and then clear the database after the scenario is complete. Does anyone know how to accomplish this or is there a better way? Thanks

    Read the article

  • jQuery querying the database

    - by mazhar kaunain baig
    The thing is that there are number of items in the HTML select list. I want to click on any of the items, then query the database on the id of that item, retrieve the value and then display that in the textbox. How would I query the database? I would really appreciate that if someone provides a code sample for querying the database.

    Read the article

  • undefined method `code' for nil:NilClass message with rails and a legacy database

    - by Jude Osborn
    I'm setting up a very simple rails 3 application to view data in a legacy MySQL database. The legacy database is mostly rails ORM compatible, except that foreign key fields are pluralized. For example, my "orders" table has a foreign key field to the "companies" table called "companies_id" (rather than "company_id"). So naturally I'm having to use the ":foreign_key" attribute of "belongs_to" to set the field name manually. I haven't used rails in a few years, but I'm pretty sure I'm doing everything right, yet I get the following error when trying to access "order.currency.code": undefined method `code' for nil:NilClass This is a very simple application so far. The only thing I've done is generate the application and a bunch of scaffolds for each of the legacy database tables. Then I've gone into some of the models to make adjustments to accommodate the above mentioned difference in database naming conventions, and added some fields to the views. That's it. No funny business. So my database tables look like this (relevant fields only): orders ------ id description invoice_number currencies_id currencies ---------- id code description My Order model looks like this: class Order < ActiveRecord::Base belongs_to :currency, :foreign_key=>'currencies_id' end My Currency model looks like this: class Currency < ActiveRecord::Base has_many :orders end The relevant view snippet looks like this: <% @orders.each do |order| %> <tr> <td><%= order.description %></td> <td><%= order.invoice_number %></td> <td><%= order.currency.code %></td> </tr> <% end %> I'm completely out of ideas. Any suggestions?

    Read the article

  • android database encryption

    - by user121196
    android uses sqlite database to store data, I need to encrypt the sqlite database, how can this be done? I understand that application data is private. However I need to explictly encrypt the sqlite database that my app is using.

    Read the article

  • Can Django be used for non web apps?

    - by Leeks and Leaks
    I noticed in the main Django introductin they show a feature that maps python objects to the database. This doesn't strike me as being mutually exclusive with with development, is there any reason why this can't be used for non web apps? Is it easy to separate out?

    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

  • Storing large json strings to database + hash

    - by Guy
    I need to store quiete large JSON data strings to the database. I am using gzip to compress the string and therefore BLOB MySQL data type to store it. However, only 5% of all the requests contain unique data and only unique data ought to be stored to the database. My approach is as follows. array_multisort data (array [a, b, c] is virtually the same as [a, c, b]). json_encode data (json_encode is faster than serialize; we need string array representation for the step 3). sha1 data (slower than md5, though less possible the collisions). Check if the hash exists in the database. 5.1 yes – do not insert the data. 5.2. no – gzip the data and store it along the hash. Is there anything about this (apart from storing JSON data to the database in the first place) that sounds fishy or should be done a different way? p.s. We are talking about a database with roughly 1kk unique records being created every month.

    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

  • Ruby Win32Api get single character non-blocking

    - by Markus Orreilly
    I'm trying to write a simple game working with two threads, one thread to get input from the user, and another thread to animate some scenes. I'm able to get characters without pressing ENTER just fine, but it blocks in the animating thread until the user presses a key. Does anyone know of a way to get a character from the keyboard non-blocking?

    Read the article

  • Configure WCF Service Behavior using database

    - by Achhar
    We use database to centralize our configuration. As part of it, I want to store the standard service behaviors configuration like expose service metatdata, service debug, service throttling for a service inside database rather than in web/app.config. I was planing to store the configuration for a behavior in database as XML. For e.g. <serviceDebug includeExceptionDetailsinFault=true / What I am struggling with is once I read this XML from database how do I create ServiceDebugBehavior instance from it and apply it to my service host? I have tried using XML Serializer but didn't had success. Any thoughts on how this could be achieved or any alternate solutions?

    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

  • Query MS Access database in VB 2008

    - by Logan
    Hi, I added an Access database as a Data Source in VB 2008. I want to query this database and use the information in various ways throughout the program. For example, there is an Employee table with first/last names of employees. I have a combobox on my form that I want to display all of the employees. So I want to query the database for all the rows in the Employee table, and add them to the combobox as I go. I am familiar with SQL Syntax, so I am not asking how to write the query itself, but rather how to fetch rows in VB code (mimicking php's mysql_fetch_assoc and mysql_connect essentially) Thanks! Edit: Also, I want to know if I can query a DB if I don't add it as a data source (if I know the path name of the database)

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 184 185 186 187 188 189 190 191 192 193 194 195  | Next Page >