生活随笔
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九、BDB OneToMany
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?(二)、OneToMany關系的存儲?
班級類:
@Entity??public?class?Classs?{??@PrimaryKey??String?classsId;???@SecondaryKey(relate=Relationship.ONE_TO_ONE)??String?classsName;???@SecondaryKey(relate=Relationship.ONE_TO_MANY,relatedEntity=Student.class,onRelatedEntityDelete=DeleteAction.CASCADE)?Set<String>?setStudent=new?HashSet<String>();???public?Classs(){??}??public?Classs(String?id,String?name){????this.classsId=id;????this.classsName=name;??}???public?Classs(String?id,String?name,Set<String>?set){????this.classsId=id;????this.classsName=name;????this.setStudent=set;??}??}??學生類:??@Entity??public?class?Student?{??@PrimaryKey??String?studentId;???@SecondaryKey(relate=Relationship.MANY_TO_ONE)??String?studentName;???@SecondaryKey(relate=Relationship.MANY_TO_ONE,relatedEntity=Classs.class,onRelatedEntityDelete=DeleteAction.NULLIFY)?String?classsId;???@SecondaryKey(relate=Relationship.MANY_TO_MANY,relatedEntity=Teacher.class,onRelatedEntityDelete=DeleteAction.NULLIFY)?Set<String>?setTeacher=new?HashSet<String>();???Student(){??}??public?Student(String?id,String?name,String?cId,Set<String>?set){????this.studentId=id;????this.studentName=name;????this.classsId=cId;????this.setTeacher=set;??}??@Override??public?String?toString()?{????return?"學生id："+this.studentId+"?姓名:?"+this.studentName;??}??}???老師類:??@Entity??public?class?Teacher?{??@PrimaryKey??String?teacherId;???@SecondaryKey(relate=Relationship.MANY_TO_ONE)??String?teacherName;???public?Teacher(){??}???public?Teacher(String?id,String?name){????this.teacherId=id;????this.teacherName=name;??}???@Override??public?String?toString()?{????return?"老師ID:"+this.teacherId+"老師Name"+this.teacherName;??}??}???關系類:??public?class?Accessor?{???PrimaryIndex<String,?Teacher>?teacherById;??SecondaryIndex<String,?String,?Teacher>?teacherByName;???PrimaryIndex<String,?Classs>?classsById;??SecondaryIndex<String,?String,?Classs>?classsByName;??SecondaryIndex<String,?String,?Classs>?classsBySetStudent;???PrimaryIndex<String,?Student>?studentById;??SecondaryIndex<String,?String,?Student>?studentByName;??SecondaryIndex<String,?String,?Student>?studentByCid;??SecondaryIndex<String,?String,?Student>?studentBySetTeacher;???public?Accessor(EntityStore?store)?throws?DatabaseException{????teacherById=store.getPrimaryIndex(String.class,?Teacher.class);????teacherByName=store.getSecondaryIndex(teacherById,?String.class,?"teacherName");????????classsById=store.getPrimaryIndex(String.class,?Classs.class);????classsByName=store.getSecondaryIndex(classsById,?String.class,?"classsName");????classsBySetStudent=store.getSecondaryIndex(classsById,?String.class,?"setStudent");????????studentById=store.getPrimaryIndex(String.class,?Student.class);????studentByName=store.getSecondaryIndex(studentById,?String.class,?"studentName");????studentByCid=store.getSecondaryIndex(studentById,?String.class,?"classsId");????studentBySetTeacher=store.getSecondaryIndex(studentById,?String.class,?"setTeacher");??}??}???test類:??????????public?class?testOne2Many?{???public?static?void?main(String[]?args)?{????Environment?env=null;????EnvironmentConfig?envconfig=new?EnvironmentConfig();????envconfig.setAllowCreate(true);????envconfig.setTransactional(true);????StoreConfig?storeconfig=new?StoreConfig();????storeconfig.setAllowCreate(true);????storeconfig.setTransactional(true);????EntityStore?entityStore=null;????try?{?????env=new?Environment(new?File("d://bdb//onetomanyje"),envconfig);?????entityStore=new?EntityStore(env,"Store",storeconfig);?????Accessor?dao=new?Accessor(entityStore);?????????PrimaryIndex<String,?Teacher>?primaryByTeacher=dao.teacherById;?????PrimaryIndex<String,?Classs>?primaryByClasss=dao.classsById;?????PrimaryIndex<String,?Student>?primaryByStudent=dao.studentById;?????SecondaryIndex<String,?String,?Student>?studentByCid=dao.studentByCid;?????Transaction?txn=env.beginTransaction(null,?null);?????????Teacher?t1=new?Teacher("100001","王偉");?????Teacher?t2=new?Teacher("100002","趙奇");?????Teacher?t3=new?Teacher("100003","劉利");?????????Set<String>?setTeacher1=new?HashSet<String>();?????setTeacher1.add("100001");?????setTeacher1.add("100002");?????????Set<String>?setTeacher2=new?HashSet<String>();?????setTeacher2.add("100001");?????setTeacher2.add("100003");?????????Set<String>?setTeacher3=new?HashSet<String>();?????setTeacher3.add("100003");?????setTeacher3.add("100002");?????????Student?stu1=new?Student("4200106310001","張三","000001",setTeacher1);?????Student?stu2=new?Student("4200106310002","李四","000001",setTeacher1);?????Student?stu3=new?Student("4200106310003","張三","000001",setTeacher1);?????Student?stu4=new?Student("4200106310004","王五","000001",setTeacher1);?????????Student?stu5=new?Student("4200106310005","趙六","000002",setTeacher2);?????Student?stu6=new?Student("4200106310006","王五","000002",setTeacher2);?????Student?stu7=new?Student("4200106310007","李四","000002",setTeacher2);?????Student?stu8=new?Student("4200106310008","李利","000002",setTeacher2);?????????Student?stu9=new?Student("4200106310009","徐咪","000003",setTeacher3);?????Student?stu10=new?Student("4200106310010","劉洪","000003",setTeacher3);?????Student?stu11=new?Student("4200106310011","吳鋒","000003",setTeacher3);?????Student?stu12=new?Student("4200106310012","許珊","000003",setTeacher3);?????????Classs?c1=new?Classs("000001","一年一班");?????Classs?c2=new?Classs("000002","一年二班");?????Classs?c3=new?Classs("000003","一年三班");?????????primaryByTeacher.put(txn,?t1);?????primaryByTeacher.put(txn,?t2);?????primaryByTeacher.put(txn,?t3);?????????primaryByClasss.put(txn,?c1);?????primaryByClasss.put(txn,?c2);?????primaryByClasss.put(txn,?c3);?????????primaryByStudent.put(txn,?stu1);?????primaryByStudent.put(txn,?stu2);?????primaryByStudent.put(txn,?stu3);?????primaryByStudent.put(txn,?stu4);?????primaryByStudent.put(txn,?stu5);?????primaryByStudent.put(txn,?stu6);?????primaryByStudent.put(txn,?stu7);?????primaryByStudent.put(txn,?stu8);?????primaryByStudent.put(txn,?stu9);?????primaryByStudent.put(txn,?stu10);?????primaryByStudent.put(txn,?stu11);?????primaryByStudent.put(txn,?stu12);?????????EntityCursor<Student>?ecStudent=null;?????EntityCursor<Classs>?ecClasss=null;?????????System.out.println("----------------通過在student中的cid得到班級里面的學生--------------------------");?????ecClasss=primaryByClasss.entities(txn,null);?????for(Classs?c:ecClasss){??????System.out.println("--------------"+c.classsName+"--------------------"+c.setStudent.toString());??????ecStudent=studentByCid.subIndex(c.classsId).entities(txn,?null);??????for(Student?s:ecStudent){???????StringBuffer?strbuf=new?StringBuffer();???????Iterator<String>?it=s.setTeacher.iterator();???????while(it.hasNext()){????????strbuf.append(primaryByTeacher.get(txn,?it.next(),?LockMode.DEFAULT).teacherName+"?");???????}???????System.out.println(s.toString()+"??班級名:?"+c.classsName+"?所有老師:?"+strbuf.toString());??????}??????ecStudent.close();?????}?????ecClasss.close();?????????System.out.println("---------------------修改班級中SetStudent-------------------------------");?????ecClasss=primaryByClasss.entities(txn,null);?????for(Classs?c:ecClasss){??????ecStudent=studentByCid.subIndex(c.classsId).entities(txn,?null);??????for(Student?s:ecStudent){???????c.setStudent.add(s.studentId);??????}??????ecClasss.update(c);??????ecStudent.close();?????}?????ecClasss.close();?????????System.out.println("------------通過得到班級中的setStudent得到學生的信息--------------------");?????ecClasss=primaryByClasss.entities(txn,null);?????for(Classs?c:ecClasss){??????System.out.println("--------------"+c.classsName+"--------------------"+c.setStudent.toString());??????Iterator<String>?it=c.setStudent.iterator();??????while(it.hasNext()){???????StringBuffer?strbuf=new?StringBuffer();???????Student?s=primaryByStudent.get(txn,it.next(),LockMode.DEFAULT);???????Iterator<String>?i=s.setTeacher.iterator();???????while(i.hasNext()){????????strbuf.append(primaryByTeacher.get(txn,?i.next(),?LockMode.DEFAULT).teacherName+"?");???????}???????System.out.println(s.toString()+"??班級名:?"+c.classsName+"?所有老師:?"+strbuf.toString());??????}?????}?????ecClasss.close();?????txn.commit();?????entityStore.close();?????env.cleanLog();?????env.close();????}catch(Exception?e){?????e.printStackTrace();????}??}??}???? 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轉載于:https://blog.51cto.com/gjbxx110/615486
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