one-to-many

问题 I have multiple tables. All tables have multiple columns that could not logically be stored in one merged table. class Foo(Model): foo_id = Column(Integer(unsigned=True), primary_key=True, nullable=False) foo_data = Column(...) class Bar(Model): bar_id = Column(Integer(unsigned=True), primary_key=True, nullable=False) bar_info = Column(...) class Baz(Model): baz_id = Column(Integer(unsigned=True), primary_key=True, nullable=False) baz_content = Column(...) Now I want to save changes in a

问题 I am using MyBatis to access the database. For that purpose I have the following classes: class ClassA { private int id; private List<ClassB> list; // public getters and setters } class ClassB { private int id; // public getters and setters } The according DAOs look like that: public interface ClassADAO { @Select("SELECT id, name, description FROM TableA WHERE id = #{id}") @Results( @Result(property = "list", javaType = List.class, column = "id", many = @Many(select = "ClassBDao

问题 I have two tables: CREATE TABLE Thing ( Id int, Name nvarchar(max) ); CREATE TABLE SubThing ( Id int, Name nvarchar(max), ThingId int (foreign key) ); I want to select all Things with a listing of SubThings and set them to a ThingViewModel. The Thing ViewModel is simple: public class ThingViewModel { public int Id { get; set; } public string Name { get; set; } public List<SubThingViewModel> SubThings { get; set; } } The SubThingViewModel is: public class SubThingViewModel { public int Id {

问题 I'm working on a project using Symfony2. But I'm running into a problem. I have an entity Purchase and another, TypePurchase. They have an OneToMany-relationship, but when I look inside of the table of TypePurchase, the Purchase entity ID is not saved. It's value is null. I already tried $types->setPurchase($this) in the addType method Purchase. But this gives me the result that only the first added entity get's an ID, the next one is again null. This is my field and ID field in Purchase: /**

问题 I am creating my first Spring-Boot-Starter-data-jpa project. I was following a tutorial on that and creating a separate application in same way. When I am starting my Spring Boot application , I am getting org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org

问题 I am creating my first Spring-Boot-Starter-data-jpa project. I was following a tutorial on that and creating a separate application in same way. When I am starting my Spring Boot application , I am getting org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org

问题 I am creating my first Spring-Boot-Starter-data-jpa project. I was following a tutorial on that and creating a separate application in same way. When I am starting my Spring Boot application , I am getting org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org

问题 I have two entities Dept and Emp (real case changed and minimized). There is 1:n association between them, i.e. properties Dept.empList and Emp.dept exist with respective annotations. I want to get List<Dept> whose elements are distinct and have collection empList eagerly initialized, using native SQL query. session.createSQLQuery("select {d.*}, {e.*} from dept d join emp e on d.id = e.dept_id") .addEntity("d", Dept.class) .addJoin("e", "d.empList") //.setResultTransformer(Criteria.DISTINCT

问题 I have two entities Department and Employee. Department has a list of Employees. And Employee has a field Department. I can create Employees and add them to to list inside Department. The Database Tables are filled as expected on persist. If I query for a Department I get the Department and the List of Employees is filled. Everything fine this way. If I query for an Employee and get the Department field it Returns null. @Entity @Table(name = "DEPARTMENT") public class Department { @Id

问题 I am struggling to understand how to handle pojos with one-to-many and many-to-many relationships with JOOQ. I store locations that are created by players (one-to-many relation). A location can hold multiple additional players who may visit it (many-to-many). The database layout comes down to the following: CREATE TABLE IF NOT EXISTS `Player` ( `player-id` INT UNSIGNED NOT NULL AUTO_INCREMENT, `player` BINARY(16) NOT NULL, PRIMARY KEY (`player-id`), UNIQUE INDEX `U_player` (`player` ASC))