foreign-keys

问题 The following are two partial tables in which I am trying to define a foreign key relationship. public class Form { [Key, Column("FormID")] public System.Guid FormGUID { get; set; } [Column("PatGUID")] public Nullable<System.Guid> PatientGUID { get; set; } } public class Patient { [Column("PatGUID")] public System.Guid PatientGUID { get; set; } [Key, Column("PatID")] public int PatientID { get; set; } } I've eliminated all but the relevant information, fields, navigations, etc. for this

问题 How do you set up a foreign key in SQL Azure? I have a database now on the Azure system. The tables in the database have an intended use such that there is one main, logically centralized table and then there are a number of tables which each describe some column in the main table. For example, if I have an age classification column in the main table, I might have a separate table which lists some categories of the age classification (as a string) and some associated index. Then the index

问题 Really hate to use other people's time, but it seems the problem is just not going away. I considered all recommendations at http://verysimple.com/2006/10/22/mysql-error-number-1005-cant-create-table-mydbsql-328_45frm-errno-150/ and at http://forums.mysql.com/read.php?22,19755,19755#msg-19755 but nothing. hope that someone points to a stupid mistake. here are the tables: CREATE TABLE IF NOT EXISTS `shop`.`category` ( `id` INT(11) NOT NULL AUTO_INCREMENT , `category_id` INT(11) NOT NULL ,

问题 I'm taking my first steps in Symfony2 entity relations. I have an entity installation, which each has one meter, and one monitor. This translates to a uni-directional relationship, which I defined as such: /** * * @ORM\OneToOne(targetEntity="InfoMeter") * @ORM\JoinColumn(name="meterid", referencedColumnName="id") */ private $meter; /** * * @ORM\OneToOne(targetEntity="InstallationsRtu") * @ORM\JoinColumn(name="monitorid", referencedColumnName="id") */ private $monitor; Each monitor can only be

问题 Lets jump to an example that illustrates a table referencing multiple tables : CREATE TABLE Corses ( ID int PRIMARY KEY, ..... ) CREATE TABLE Questions ( ID int PRIMARY KEY, ..... ) CREATE TABLE Answers ( ID int PRIMARY KEY, ..... ) CREATE TABLE Files ( ID INT PRIMARY KEY, Corse_ID INT, Question_ID INT, Answer_ID INT, FOREIGN KEY (Corse_ID) REFERENCES Corses(ID), FOREIGN KEY (Question_ID) REFERENCES Questions(ID), FOREIGN KEY (Answer_ID) REFERENCES Answers(ID) ) The example above illustrates

问题 A company provides transport services to high-ranked staffs. There are 3 tables: DRIVERS, VEHICLES, STAFFS. DRIVERS - license number [PK] - name - language spoken - ... (and so on..) VEHICLES - vehicle ID [PK] - registration number - model - colour - ... and so on... STAFFS - staff ID [PK] - name - position name - ... and so on.... I want to create a new table called ORGANIZE whereby, it will assign a driver and a vehicle to match the needs of the staff. what will be the PK and FKs? 回答1: I've

问题 So I have the following SQL commands for the description below. I am not sure I have the constraints right especially for the foreign keys, and when to use not null and when not too. Can someone verify if the commands are correct, based on the database description? Car Dealerships have a unique business id number, dealership name, city, state, and a unique website URL. The business id is a number in the range from 1000-9999. Salespersons have a first name, last name, age, gender, and a unique

问题 I have the below code that should add user input into the db, I can't understand why its not adding to db, the email field in the table is a foreign key that references to another table, and I'm using session to store email in the $email and save it to db when user saves data, also I'm accepting date and time from user input which is exactly as per the db format but it still doesn't save, I have tried entering static data as well, not working either. Am I missing something ? $server =

问题 I added to my "Todo" class a foreignKey to my "Pharmacy" class. When I add or edit a Todo, no Pharmacy can be linked (from a selectbox). Here's my model: public class Todo { [Key] public int ID { get; set; } public Pharmacy Pharmacy { get; set; } } public class Pharmacy { [Key] public int PharmacyID { get; set; } public string Name { get; set; } public string Pharmacist { get; set; } [DataType(DataType.PhoneNumber)] public int Phone { get; set; } [DataType(DataType.EmailAddress)] public

问题 In my django formset , I am trying to display a foreign key field with an input instead of a select : class MinAttend(models.Model): act = models.ForeignKey(Act) country = models.ForeignKey(Country) verbatim = models.ForeignKey(Verbatim) def __unicode__(self): return u"%s" % self.verbatim class MinAttendForm(forms.ModelForm): country=forms.ModelChoiceField(queryset=Country.objects.all(), empty_label="Select a country") status=forms.ModelChoiceField(queryset=Status.objects.values_list('status'