Cascade

问题 I have 2 entities: 1) User 2) Department. each contains a SET of the other since the relationship between them is manyToMany, I marked (CascadeType.ALL) on the user entity and the department entity and when i do : userX.getDepartments.remove(departmentX); save(userX); it works like intended - it actually implies that departmentX.getUsers.contains(userX) == false. is called implicitly. BUT , when i do departmentY.getUsers.remove(userX); save(departmentY); it doesn't cascade! meaning - i can do

问题 I am starting to experiment with using InnoDB in web applications. I've setup some tables with a foreign key, but they are not behaving as expected. Here are my table CREATE statements: CREATE TABLE sections ( section_id INT NOT NULL AUTO_INCREMENT, title VARCHAR(30), created_at int(10) NOT NULL, updated_at int(10) NOT NULL, PRIMARY KEY(section_id) ) ENGINE=InnoDB; CREATE TABLE pages ( page_id INT NOT NULL AUTO_INCREMENT, section_idfk INT NOT NULL, PRIMARY KEY(page_id), FOREIGN KEY(section

问题 I am having some trouble formulating a solution for this foreseen situation. TableA has a FK to TableB. TableC has a FK to TableA. TableC has a FK to TableD. TableA ------ taId tbId TableB ------ tbId TableC ------ tcId taId tdId TableD ------ tdId A brief series of events: 1) A cascade soft-delete is issued to a record in TableB. This causes all related records in TableA to be soft-deleted, cascading to all related records in TableC being soft-deleted. 2) At a later time, a record in TableD

问题 I am having some trouble formulating a solution for this foreseen situation. TableA has a FK to TableB. TableC has a FK to TableA. TableC has a FK to TableD. TableA ------ taId tbId TableB ------ tbId TableC ------ tcId taId tdId TableD ------ tdId A brief series of events: 1) A cascade soft-delete is issued to a record in TableB. This causes all related records in TableA to be soft-deleted, cascading to all related records in TableC being soft-deleted. 2) At a later time, a record in TableD

问题 Right now, I have a word that I'm search for in a larger string if the word is not found then I insert the word in the larger sting. The output of the first FOR loop is cascaded into a second FOR loop. This work's ok, with one or two but if I had 100's or 1000's of searchs it would be a pain to do this each time is there a better python 3 way? As you can see from the example I'm looking for Monday in the first string monday is there so it just skips the second string does not have Monday so

问题 I have a table Communication which has a reference to PersonCompany. In the mapping for PersonCompany i have defined a Cascade-Delete for this reference: this.HasMany(x => x.Communications) .AsSet() .KeyColumn("PersonCompanyId") .Fetch.Select() .Inverse() .Cascade.Delete(); But when I now execute the fallowing HQL-Query: var sql = "delete from PersonCompany where Person.Id in (:idList) or Company.Id in (:idList)"; with var query = NHibernateHelper.CurrentSession.CreateQuery(sql); query

问题 I have two tables in an existing (MSSQL 2008 R2) database that are related by a link table. The two tables are "Plan" and "Tips". The link table is "PlanTipLinks". Plans can have many tips, and tips can be associated with multiple plans (i.e. it's a many-to-many relationship). In the application, I only care about the "Plan.Tips" relationship. I don't need the Tip.Plans inverse relationship. The foreign key references in the link table cannot be null. I'm using the following fluent API code

问题 Performance is key: Is it better to cascade deletes/updates inside of the Database or let Hibernate/JPA take care of it? Will this effect the ability to query for the data if cascades are inside of the DBMS? I am using HSQLDB if that matters. 回答1: In the case of cascading updates, you simply cannot do it in application space if you have foreign key constraints in the database. Example: say you have a lookup table for US states, with a primary key of the two-letter abbreviation. Then you have

问题 In an application I use EclipseLink 2.4.1 with Java Persistence 2.0.4. I have a OneToOne mapping in an embedded class. Everything works fine, except deleting. When I try to delete the object containing the embedded class, the following exception occurs. I checked and I am not calling remove on the embedded object by myself somewhere in the code. Does anybody knows how to avoid this error or how to get around it? Exception [EclipseLink-6002] (Eclipse Persistence Services - 2.4.1.v20121003

问题 I am trying to cascade delete rows in a join table via one of its foreign keys and it has another table related to it that I would like to remove all rows associated with this ID as well. So it looks like the diagram below. When I use Session.delete(reqCandObject) with hibernate it works fine and cascades through deleting the One entry from the candidate_jobReq table as well as the associated comments. However, I want to delete all of the candidate_jobReq entries that have a certain candidate