relationship | 易学教程

Cosine similarity vs Hamming distance [closed]

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To compute the similarity between two documents, I create a feature vector containing the term frequencies. But then, for the next step, I can't decide between " Cosine similarity " and " Hamming distance ". My question: Do you have experience with these algorithms? Which one gives you better results? In addition to that: Could you tell me how to code the Cosine similarity in PHP? For Hamming distance, I've already got the code: function check ($terms1, $terms2) { $counts1 = array_count_values($terms1); $totalScore = 0; foreach ($terms2 as $term) { if (isset($counts1[$term])) $totalScore +=

Grails GORM domain association across two datasources

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问题 Is it possible to have an association between two domain classes (i.e. belongsTo ) if the other domain class uses a different datasource? The two datasources are different database drivers too. I suspect this may not be possible, but I wanted to reach out to the community here to see if it was possible. Right now I'm trying to do it and I am getting the usual suspected Hibernate error: Invocation of init method failed; nested exception is org.hibernate.MappingException: An association from

How to use an include with attributes with sequelize?

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问题 Any idea how to use an include with attributes (when you need to include only specific fields of the included table) with sequelize? Currently I have this (but it doesn't work as expected): var attributes = ['id', 'name', 'bar.version', ['bar.last_modified', 'changed']]; foo.findAll({ where : where, attributes : attributes, include : [bar] }).success(function (result) { ... 回答1: Something like this should work foo.findAll({ where : where, attributes : attributes, include : [{ model: bar,

How to find all the relations between all mysql tables?

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How to find all the relations between all MySQL tables? If for example, I want to know the relation of tables in a database of having around 100 tables. Is there anyway to know this? The better way, programmatically speaking, is gathering data from INFORMATION_SCHEMA.KEY_COLUMN_USAGE table as follows: SELECT `TABLE_SCHEMA`, -- Foreign key schema `TABLE_NAME`, -- Foreign key table `COLUMN_NAME`, -- Foreign key column `REFERENCED_TABLE_SCHEMA`, -- Origin key schema `REFERENCED_TABLE_NAME`, -- Origin key table `REFERENCED_COLUMN_NAME` -- Origin key column FROM `INFORMATION_SCHEMA`.`KEY_COLUMN

What Kind of Relationship is Between These Tables?

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I have two tables that have foreign keys to each other's primary key. This DB is in French. I will translate the two tables that I want to you to understand. Atelier Cuisine ==> Kitchen Cuisinier == > Cooking chef So in this picture we see that in the Kitchen table we have a PK referenced by the FK from the Cooking chef table; in the Cooking chef table we have a PK referenced by the FK from the Kitchen table. So I am confused. I don't understand this kind of relationship between these tables. And I hope to check my query that I did to create these two tables if its correct CREATE TABLE

Relationships in Doctrine

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问题 I have 2 Entities: Categories and products. How can I build a relationship between these Entities? Category Entity: class Category { private $id; private $name; private $parent; public function getChildren() { return $this->children; } //setters and getters } Items Entity: class Items { private $id; private $name; private $price; private $color; private $size; private $weight; //getters and setters } Category yml: AppBundle\Entity\Category: type: entity oneToMany: children: targetEntity:

HABTM Polymorphic Relationship

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I'm pretty new to Rails, and i'm trying to do a polymorphic HABTM relationship. The problem is that I have three models that I want to relate. The first one is the Event model and then are two kind of attendees: Users and Contacts. What I want to do is to be able to relate as an attendee both users and contacts. So, what i have right now in my code is: Event Model has_and_belongs_to_many :attendees, :polymorphic => true User Model has_and_belongs_to_many :events, :as => :attendees Contact Model has_and_belongs_to_may :events, :as => :attendees How the HABTM table migration needs to be? I'm a

Laravel Eloquent - Attach vs Sync

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What is the difference between attach() and sync() in Laravel 4's Eloquent ORM? I've tried to look around but couldn't find anything! attach(): Insert related models when working with many-to-many relations No array parameter is expected Example: $user = User::find(1); $user->roles()->attach(1); sync() Similar to the attach() method. sync() also use to attach related models. However main difference is: Sync method accepts an array of IDs to place on the pivot table Secondly, most important , The sync method will delete the models from table if model does not exist in array and insert new items

How do I access the properties of a many-to-many “through” table from a django template?

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问题 From the Django documentation... When you're only dealing with simple many-to-many relationships such as mixing and matching pizzas and toppings, a standard ManyToManyField is all you need. However, sometimes you may need to associate data with the relationship between two models. For example, consider the case of an application tracking the musical groups which musicians belong to. There is a many-to-many relationship between a person and the groups of which they are a member, so you could

Laravel save / update many to many relationship

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问题 Can anyone help me on how to save many to many relationship? I have tasks, user can have many tasks and task can have many users (many to many), What I want to achieve is that in update form admin can assign multiple users to specific task. This is done through html multiple select input name="taskParticipants[]" The catch here is that through the same form (input) you can add/remove users, that's why I have to use sync(). Maybe I should start from the beginning but don't know where to start.