relationship

问题 My request is very similar to Retrieving parent plus related children in one Parse REST API call, however I didn't see the final RESTful command which populated the related children. I can obviously make multiple RESTful calls but this is redundant and introduces undesired latency. I'd rather be able to make a join request in my RESTful query. Alternatively I could build out a job that returns the EventSeries + Children Events but that seems inappropriate and would introduce additional

问题 I updated my entity file to include relationship mapping. Persist worked before the update now it doesn't. Maybe it's something I forgot to do. namespace classes\classBundle\Entity; use Doctrine\ORM\Mapping as ORM; /** * advisersplans * * @ORM\Table() * @ORM\Entity */ class advisersPlans { /** * * @ORM\ManyToOne(targetEntity="plans", inversedBy="adviserPlans") * @ORM\JoinColumn(name="planid", referencedColumnName="id") */ public $plan; /** * @var integer * * @ORM\Column(name="id", type=

问题 I have 3 Models. Project {id, name} Platform {id, name} Version {id, value} One Project can have multiple Platforms and each Platform can have multiple Versions within a Project . I have the following table which relates the models: As you can see Project 6 has versions 1 and 3 on platform 1, while Project 8 has versions 1 and 2 on the same platform. I want to get all Projects' Platforms and versions of those Platforms depending on the Project. For example, I'd like to do App\Project::find(6)

问题 I am trying to retrieve database rows with their relationships. However, the local key is an array. Let me explain using an example. Lets say I have a table of countries and a table of pages. Each country can have many pages. Each page can belong to multiple countries. I do not have the flexibility to change this schema. pages +-------------+-----------+ | id | name | countries | +-------------+-----------+ | 1 | Page 1 | 1 | +-------------+-----------+ | 2 | Page 2 | 1,2,3 | +-------------+-

问题 I am currently looking at modelling tertiary courses and other such entities (MATH101, BIOL360, BSc etc.), and one of the options we're looking at is graph databases. I am not familiar with graph databases, other than in theory. One of the things I am trying to model is requirements, for example "MATH201 requires the student previously completed MATH101". That one seems easy - I can create a vertex between the two. Others are more complicated: "Bachelor of Computer Science requires 40 points

问题 I just found out that officially relationships/foreign keys to non-primary key columns aren't supported by JPA. See here: Does the JPA specification allow references to non-primary key columns? Why do such relationships map in Hibernate and EclipseLink nontheless (only in JPA 1.0 syntax as in the example posted there)?? It appears that these JPA providers just map the columns naively, which I think is a good thing, but I'd like to know explicitly. Is it coincidence? Is it intended? 回答1:

问题 Using a MS Acess 2007 database accessed by vb.net application I have two existing table Members ------- ID name bandID ----------------------- 0 Pierre 1 1 Chart 3 2 John 3 3 Dave 2 Bands ----- ID bandName ---------------- 1 Band a 2 Band b 3 Band c I want to add an cascade to null constraint to the relation between members.bandId and bands.ID This is what I have ALTER TABLE members ADD CONSTRAINT membresBands_FK FOREIGN KEY (bandID) REFERENCE Bands(ID) ON DELETE CASCADE SET NULL But I get

问题 I have this table CREATE TABLE [dbo].[CityMaster]( [CityID] [int] NOT NULL, [City] [varchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [BranchId] [varchar](10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL CONSTRAINT [DF__CityM__Branc__74444068] DEFAULT ((0)), [ExternalBranchId] [varchar](max) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, CONSTRAINT [PK_CityMaster] PRIMARY KEY CLUSTERED ( [City] ASC, [BranchId] ASC ), CONSTRAINT [uk_citymaster_cityid_branchid] UNIQUE NONCLUSTERED (

问题 Are cookies and sessions depend on each other in PHP? Does deleting or clearing either one of them affect the other? Does by disabling either one of them in the browser affect the other? P.S. I am newbie. Edit : I was newbie at time of writing question. This question is faced by many newbies. 回答1: They are totally independent ... Cookies cannot store unlimited value, sessions can You cannot store data in a cookie if user browser cookie is disabled where in session you can, because session id

问题 I'm not sure what has changed getting this error when trying to login: ERROR: relation "tags" does not exist LINE 1: SELECT DISTINCT "tags".* FROM "tags" INNER JOIN "taggings" O... The tag model: class Tag < ActiveRecord::Base attr_accessor :unread_count, :user_feeds has_many :taggings has_many :feeds, through: :taggings end The tagging model: class Tagging < ActiveRecord::Base belongs_to :tag belongs_to :feed belongs_to :user end And the user relationships: class User < ActiveRecord::Base