foreign-keys

In PostgreSQL I have a database, which I intend to make the following table declaration: CREATE TABLE canvas_user ( id INTEGER, login_id VARCHAR(50) UNIQUE NOT NULL, email VARCHAR(355) UNIQUE NOT NULL, name_given VARCHAR(30), name_family VARCHAR(30), name_full VARCHAR(50), role canvas_role, last_login TIMESTAMP, PRIMARY KEY (id) ); CREATE TABLE problem ( id SERIAL, title VARCHAR(50), author VARCHAR(50), path TEXT, compiler VARCHAR(20), PRIMARY KEY (id) ); CREATE TABLE assignment ( id INTEGER, title TEXT NOT NULL, points_possible INTEGER NOT NULL, problem_id INTEGER, PRIMARY KEY (id), FOREIGN

I am building a database as a simple exercise, it could be hosted on any database server, so I am trying to keep things as much standard as possible. Basically what I would like to do is a 'code' table that get referenced by other entities. I explain: xcode id code r role p property code r admin r staff p title .... then I would like to have some view like: role (select * from code where xcode='r') r admin r staff property (select * from code where xcode='p') p title then, suppose we have an entity myentity id - 1 role - admin (foreign key to role) title - title (foreign key to property)

I stumble upon strange behavior with innoDB constraint, and cannot find cause of it. I have tables with data. Below listed their structures: CREATE TABLE `contents` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `title` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`), KEY `title` (`title`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE `fields` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(45) NOT NULL, `type` varchar(45) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `nameUNIQUE` (`name`), KEY `name` (`name`), KEY `type` (`type`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE

I have 3 tables Student Loan Book - StudentID LoanID BookID which foreign keys do i need to set so when given the student name, search all loan from that student and display the book detail Here's a start with such vague requirements: CREATE TABLE dbo.Students ( StudentID INT PRIMARY KEY -- , other columns about students ); CREATE TABLE dbo.Loans ( LoanID INT PRIMARY KEY, StudentID INT NOT NULL FOREIGN KEY REFERENCES dbo.Students(StudentID) -- , other columns about loans ); CREATE TABLE dbo.Books ( BookID INT PRIMARY KEY, -- , other columns about books ); CREATE TABLE dbo.StudentBooks (

I have a question regarding explicitly defining of the uniqueness of something. This relates to the creation of a composite foreign key. I've created an example below to try and make my question as clear as possible (I've included some data inserts for ease of testing). Each entry for [Table1] must have a unique [Name] . CREATE TABLE [Table1] ( [ID] INT IDENTITY NOT NULL PRIMARY KEY, [Name] NVARCHAR(255) UNIQUE NOT NULL CHECK(LTRIM(RTRIM([Name])) <> '') ); INSERT INTO [Table1]([Name]) VALUES ('Name 1'), ('Name 2'), ('Name 3'), ('Name 4'), ('Name 5'), ('Name 6'), ('Name 7') Each [Value] in

Using EF5 Code first, I have two classes: [Table("UserProfile")] public class UserProfile { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int UserId { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public DateTime DateOfBirth { get; set; } [ForeignKey("AddressId")] public virtual Address Address { get; set; } } [Table("Address")] public class Address : IEntity { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int AddressId { get; set; } public string Address1 { get; set; } public string Address2 { get; set; }

I want to create a table in MySQL by running following SQL, CREATE TABLE IF NOT EXISTS `shrewd_db`.`alert_disable_register` ( `id_alert_disable_register` MEDIUMINT NOT NULL AUTO_INCREMENT, `id_label` MEDIUMINT UNSIGNED NULL, `id_indicator` MEDIUMINT UNSIGNED NULL, `id_user` MEDIUMINT UNSIGNED NULL, `active` TINYINT(1) NULL DEFAULT 1, `id_alert_disable_rule` MEDIUMINT NULL, `id_escalation_plan` INT NULL, PRIMARY KEY (`id_alert_disable_register`), INDEX `id_escalation_plan_alert_rule_idx` (`id_alert_disable_rule` ASC), INDEX `id_label_idx` (`id_label` ASC), INDEX `id_indicator_idx` (`id