foreign-keys

问题 I got a OneToMany relation between User and Group Group.java @Entity public class Group { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; private String groupid; @ManyToOne @JoinColumn(name="USER_FK") private User user; ... } User.java @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; private String userId; private String password; private String fname; private String lname; @OneToMany(mappedBy="user", cascade=CascadeType.ALL

问题 I have a django app which basically is just a photo album. Right now I have two models: Image and Album . Among other things, each Album has a foreign key to an Image to be its thumbnail and each Image has a foreign key to the Album it belongs in. However, when I try to use manage.py syncdb or manage.py sqlall I get errors saying the class not defined first in models.py isn't defined when it is used in the first class defined. models.py (abridged): from django.db import models import os class

问题 Since this mornong i am facing a very big problem. I am using CodeIgniter to develop a website, and GAS ORM for the database. I have basically two tables. One named "pool", and one named "partners". I am having two associations between these two tables, so I have two foreign keys in my table Partners referencing the table pool. Pool(#id:integer, name:varchar) Partners(#id:integer, associated_pool_id=>Pool, futur_associated_pool_id=>Pool). As I have two references to the same table, I can't

问题 I want to know if there is a way to have multiple values in a single field in a MySQL database where each value is a foreign key referencing one other table. I am designing a database with a product table and a product certification table. I am using InnoDB and foreign key constraints. The "product" table contains the details about specific instances of the product. One of the details contained in the product table is the column “product_certification_id”, which is a foreign key referencing

问题 I have been having this problem for a couple of hours now. In SQL Server , I ran this query : INSERT INTO USERS_AVATAR(userId, avatId) VALUES ('1', '213'); INSERT INTO USERS_AVATAR(userId, avatId) VALUES ('2', '312'); but the message shows up saying : Msg 547, Level 16, State 0, Line 1 The INSERT statement conflicted with the FOREIGN KEY constraint "FKUSERS_AVAT731248". The conflict occurred in database "gk314", table "gk314.USERS", column 'userId'. Msg 547, Level 16, State 0, Line 2 The

问题 I am trying to build an ecommerce site in Django 1.7 everything works except when I try to use the checkout, I got the following error. I am not sure wht it is doing this as it works fine on my localhost but not when I try to deploy on webfaction. Many thanks Environment: Request Method: GET Request URL: http://myshoppingapp.com/checkout/ Django Version: 1.7.1 Python Version: 2.7.9 Installed Applications: ('django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django

问题 I am trying to build an ecommerce site in Django 1.7 everything works except when I try to use the checkout, I got the following error. I am not sure wht it is doing this as it works fine on my localhost but not when I try to deploy on webfaction. Many thanks Environment: Request Method: GET Request URL: http://myshoppingapp.com/checkout/ Django Version: 1.7.1 Python Version: 2.7.9 Installed Applications: ('django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django

问题 I am trying to create a database with multiple foreign keys with delete/ update constraints, but I got a error code 1005 with following sql scripts: CREATE TABLE Worker ( WorkerID smallint auto_increment, WorkerType varchar(45) NOT NULL, WorkerName varchar(45) NOT NULL, Position varchar(45) NOT NULL, TaxFileNumber int NOT NULL, Address varchar(100) , Phone varchar(20) , SupervisorID smallint , PRIMARY KEY (WorkerID), FOREIGN KEY (SupervisorID) REFERENCES Worker(WorkerID) ON DELETE SET NULL ON

问题 I already checked out this question, and thought I had the answer - but then it didn't look right to me. I have the following pared down example: CREATE TABLE pipelines ( name VARCHAR NOT NULL, owner VARCHAR NOT NULL, description VARCHAR, PRIMARY KEY (name, owner), FOREIGN KEY(owner) REFERENCES user (id) ); CREATE TABLE tasks ( id INTEGER NOT NULL, title VARCHAR, pipeline VARCHAR, owner VARCHAR, PRIMARY KEY (id), FOREIGN KEY(pipeline) REFERENCES pipelines (name), FOREIGN KEY(owner) REFERENCES

问题 I already checked out this question, and thought I had the answer - but then it didn't look right to me. I have the following pared down example: CREATE TABLE pipelines ( name VARCHAR NOT NULL, owner VARCHAR NOT NULL, description VARCHAR, PRIMARY KEY (name, owner), FOREIGN KEY(owner) REFERENCES user (id) ); CREATE TABLE tasks ( id INTEGER NOT NULL, title VARCHAR, pipeline VARCHAR, owner VARCHAR, PRIMARY KEY (id), FOREIGN KEY(pipeline) REFERENCES pipelines (name), FOREIGN KEY(owner) REFERENCES