composite-key

问题 I'm using a CRUD framework called Tynamo, which in turn relies on Apache Tapestry and Hibernate. This all works fine, except for when I try to use it for CRUD on a table with a composite/compound primary key. I've decided not to go the @EmbeddedId route, since it seems to not work at all with the framework. That being said, I have been using the @IdClass method, which is mostly working; I think I'm a line or two of code away from success. The issue is that when it starts using reflection to

问题 I want to query data filtering by composite keys other than Row Key in CQL3. These are my queries: CREATE TABLE grades (id int, date timestamp, subject text, status text, PRIMARY KEY (id, subject, status, date) ); When I try and access the data, SELECT * FROM grades where id = 1098; //works fine SELECT * FROM grades where subject = 'English' ALLOW FILTERING; //works fine SELECT * FROM grades where status = 'Active' ALLOW FILTERING; //gives an error Bad Request: PRIMARY KEY part status cannot

问题 I am making a database of students in one school.Here is what I have so far: If you don't like reading jump to the "In short" part The problem is that I'm not happy with this design. I want the combination of grade , subgrade and id_class to be unique and to serve as a primary key for the students table. I can remove the student_id and make a composite key from the 3 but I don't want that either. Maybe I should make another table lets say combination_id where grade , subgrade and id_class are

问题 I am making a database of students in one school.Here is what I have so far: If you don't like reading jump to the "In short" part The problem is that I'm not happy with this design. I want the combination of grade , subgrade and id_class to be unique and to serve as a primary key for the students table. I can remove the student_id and make a composite key from the 3 but I don't want that either. Maybe I should make another table lets say combination_id where grade , subgrade and id_class are

问题 I have a model called "EventCheckin" which has a ManyToOne mapping to an "Event" and a "User". The PrimaryKey of the "EventCheckin" table is the id of the user and the id of the event. I'm trying to represent this using an "EmbeddedId" in my EventCheckin model but when I attempt to save an EventCheckin it tries to put the user_id and event_id values into the table twice which obviously fails: Caused by: org.h2.jdbc.JdbcSQLException: Duplicate column name "USER_ID"; SQL statement: insert into

问题 I was playing with EntityFramework CTP4 and decided to apply it to one of my current projects. The application uses a SQLServer database and there is one table with a composite key. Say, table "MyEntity" has "Key1" and "Key2" as both foreign keys (individually) and as a composite primary key. I made a configuration class derived from EntityConfiguration : class MyEntityConfiguration : EntityConfiguration<MyEntity> { public MyEntityConfiguration() { HasKey(m => m.Key1); HasKey(m => m.Key2); }

问题 I'm facing a problem with Ebean when trying to create Composed Keys (EmbeddedId). This is a draft of what I have: @Entity public class EntityA extends Model{ @Id private String ID; @OneToMany private List<EntityB> listEntitesB; public EntityA(){ ID = UUID.randomUUID(); } } @Entity public class EntityB extends Model{ @EmbeddedId private EntityB_PK ID; @ManyToOne @JoinColumn(name="entityA_fk", referencedColumnName="listEntitiesB") private EntityA entityA; public EntityB(String entityB_ID){ ID =

问题 i try to create composite primary key in table from 2 foreign key using hibernate JPA,but gives me error.I find some solution on net but nothing The relations between tables looks like this: Table Client clientID(PK) FirstName LastName . Table CarService serviceID(PK) DescriptionOfFailure . . Table ServiceDepartment clientID(PK) serviceID(PK) price . implementation of my code looks like this: @Entity public class ServiceDepartmentBean implements ServiceDepartmentI { @EmbeddedId private

问题 Shortly, I want to create composite keys on my table remaining with the primary key in order to improve sql server search performance. The performance issue occurs on 200k data table whenever I search an entity without primary key (i.e a string of GUID). Assume that I have 3 classes public class Device{ public int ID { get; set; } public string UDID { get; set; } public string ApplicationKey { get; set; } public string PlatformKey { get; set; } public ICollection<NotificationMessageDevice>

问题 Just beginning to learn about SQL and had a question I couldn't figure out. I have a setup based on the following tables and their primary keys, the columns with the same name between tables are constrained by foreign keys: Company: CompanyId Division: CompanyId DivisionId Resource: CompanyId ResourceId DivisionResource : CompanyId DivisionId ResourceId DivisionResource is used to create a many to many relation between division and resource and constrain them so that divisions can only be