GreenDao基本使用

一.背景

之前用dbFlow,但是因为某些原因不适合所有机型，所以准备用GreenDao,所以现在写篇文章记录一下使用的基本要点。

二.基本知识点和坑

• 增
  mUser = new User((long)2,”anye3”);
  mUserDao.insert(mUser);//添加一个

• 删
  mUserDao.deleteByKey(id);

• 改
  mUser = new User((long)2,”anye0803”);
  mUserDao.update(mUser);

• 查
  List users = mUserDao.loadAll();
  String userName = “”;
  for (int i = 0; i < users.size(); i++) {
  userName += users.get(i).getName()+”,”;
  }
  mContext.setText(“查询全部数据==>”+userName);

• 实体@Entity注解
  schema：告知GreenDao当前实体属于哪个schema
  active：标记一个实体处于活动状态，活动实体有更新、删除和刷新方法
  nameInDb：在数据中使用的别名，默认使用的是实体的类名
  indexes：定义索引，可以跨越多个列
  createInDb：是否创建表，默认为true,false时不创建

• 基础属性注解
  @Id :主键 Long型，可以通过@Id(autoincrement = true)设置自增长
  @Property：设置一个非默认关系映射所对应的列名，默认是的使用字段名 举例：@Property (nameInDb=”name”)
  @NotNul：设置数据库表当前列不能为空
  @Transient ：添加次标记之后不会生成数据库表的列

• 索引注解
  @Index：使用@Index作为一个属性来创建一个索引，通过name设置索引别名，也可以通过unique给索引添加约束
  @Unique：向数据库列添加了一个唯一的约束
  @OrderBy 排序
  @generated 由greendao产生的构造函数或方法

• 关系注解
  @ToOne：定义与另一个实体（一个实体对象）的关系
  @ToMany：定义与多个实体对象的关系

• 坑one
  greendao的关联关系是通过主外键（对象之间关联的id）来构建的。realm是直接通过对象关系来自动构建的。

• 坑two
  如果属性是List<> xx, greendao不会自动调用设置xx的值，只有手动调用getXX的时候获取.我在打印log的时候被坑惨了，无论怎么样都是为null.

• 数据库升级
  如果某张表修改了字段，或者新增了一张表，必须要修改build.gradle中的schemaVersion，否则当你升级app的时候，如果进行了数据库操作，会发现列不匹配或者表不存在等问题，直接会导致app闪退。但是如果仅仅是将schemaVersion加1，虽然程序不会崩溃，并且数据表的结构也会更新成功，但是之前表中的数据会全部清空。我们需要进行手动操作来进行数据库里面的数据迁移，大致的思路是：创建临时表（结构与上一版本的表结构相同），将旧数据移到临时表中，删除旧版本的表，创建新版本的表，将临时表中的数据转移到新表中，最后再删除临时表。详细方法见链接：
  http://stackoverflow.com/a/30334668/5995409

• 自定义sql语句

ChatHistoryDao dao = GreenDaoManager.getInstance().getSession().getChatHistoryDao();  Cursor cursor = dao.getDatabase().rawQuery("select t.sales_wx_nick_name,t.wx_nick_name,count(*),t.talker_id,t.sales_wx_account from chat_history t group by t.talker_id,t.sales_wx_account order by t.created_at desc", null);  while (cursor.moveToNext()) {      String salesWxNickName = cursor.getString(0);      String clientWxNickName = cursor.getString(1);      int chatCount = cursor.getInt(2);      int talkerId = cursor.getInt(3);      String salesWxAccount = cursor.getString(4);  }      有的时候需要用到group by或者left join等复杂的语句，可以调用android原生的sqlite去进行查询。

三.例子（oneToone,oneTomany,manyTomany）

• 一对一
  一个人只有一个职业(socialRole)
  我们用 @ToOne(joinProperty = “socialRoleId”),然后把SocialRole的Id设置给Person的socialRoleId就建立联系了，不需setSocialRole!!!!!!
  Person.java

@Entitypublic class Person {    @Id    private Long id;    @Property(nameInDb = "address")    private String personAddress;    private Long socialRoleId;    private String name;    @ToOne(joinProperty = "socialRoleId")    private SocialRole socialRole;    @ToMany(referencedJoinProperty = "authorId")    private List<Article> articleList;    /** Used to resolve relations */    @Keep    private transient com.rebase.greendao.entity.DaoSession daoSession;    /** Used for active entity operations. */    @Keep    private transient com.rebase.greendao.entity.PersonDao myDao;    @Keep    public Person(Long id, String personAddress, Long socialRoleId, String name) {        this.id = id;        this.personAddress = personAddress;        this.socialRoleId = socialRoleId;        this.name = name;    }    @Keep    public Person() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getPersonAddress() {        return this.personAddress;    }    public void setPersonAddress(String personAddress) {        this.personAddress = personAddress;    }    public Long getSocialRoleId() {        return this.socialRoleId;    }    public void setSocialRoleId(Long socialRoleId) {        this.socialRoleId = socialRoleId;    }    @Keep    private transient Long socialRole__resolvedKey;    /** To-one relationship, resolved on first access. */    @Keep    public SocialRole getSocialRole() {        Long __key = this.socialRoleId;        if (socialRole__resolvedKey == null || !socialRole__resolvedKey.equals(__key)) {            final com.rebase.greendao.entity.DaoSession daoSession = this.daoSession;            if (daoSession == null) {                throw new DaoException("Entity is detached from DAO context");            }            com.rebase.greendao.entity.SocialRoleDao targetDao = daoSession.getSocialRoleDao();            SocialRole socialRoleNew = targetDao.load(__key);            synchronized (this) {                socialRole = socialRoleNew;                socialRole__resolvedKey = __key;            }        }        return socialRole;    }    /** called by internal mechanisms, do not call yourself. */    @Keep    public void setSocialRole(SocialRole socialRole) {        synchronized (this) {            this.socialRole = socialRole;            socialRoleId = socialRole == null ? null : socialRole.getId();            socialRole__resolvedKey = socialRoleId;        }    }    /**     * To-many relationship, resolved on first access (and after reset).     * Changes to to-many relations are not persisted, make changes to the target entity.     */    @Keep    public List<Article> getArticleList() {        if (articleList == null) {            final com.rebase.greendao.entity.DaoSession daoSession = this.daoSession;            if (daoSession == null) {                throw new DaoException("Entity is detached from DAO context");            }            com.rebase.greendao.entity.ArticleDao targetDao = daoSession.getArticleDao();            List<Article> articleListNew = targetDao._queryPerson_ArticleList(id);            synchronized (this) {                if (articleList == null) {                    articleList = articleListNew;                }            }        }        return articleList;    }    /** Resets a to-many relationship, making the next get call to query for a fresh result. */    @Keep    public synchronized void resetArticleList() {        articleList = null;    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#delete(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void delete() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.delete(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#refresh(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void refresh() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.refresh(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#update(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void update() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.update(this);    }    public String getName() {        return this.name;    }    public void setName(String name) {        this.name = name;    }    /** called by internal mechanisms, do not call yourself. */    @Keep    public void __setDaoSession(com.rebase.greendao.entity.DaoSession daoSession) {        this.daoSession = daoSession;        myDao = daoSession != null ? daoSession.getPersonDao() : null;    }}

SocialRole.java

@Entitypublic class SocialRole {    @Id    private Long id;    @Property(nameInDb = "job")    private String jobDesc;    private int salary;    @Generated(hash = 764507058)    public SocialRole(Long id, String jobDesc, int salary) {        this.id = id;        this.jobDesc = jobDesc;        this.salary = salary;    }    @Generated(hash = 508250821)    public SocialRole() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getJobDesc() {        return this.jobDesc;    }    public void setJobDesc(String jobDesc) {        this.jobDesc = jobDesc;    }    public int getSalary() {        return this.salary;    }    public void setSalary(int salary) {        this.salary = salary;    }    @Override    public String toString() {        return "SocialRole{" +                "id=" + id +                ", jobDesc='" + jobDesc + '\'' +                ", salary=" + salary +                '}';    }}

然后初始化

 mPerson = mDaoSession.getPersonDao().queryBuilder().where(PersonDao.Properties.Name.eq("Jason")).unique();        if (mPerson == null) {            Person person = new Person();            person.setPersonAddress("shanghai");            person.setName("Jason");            mPerson = person;        }        System.out.println("xcqw person"+mPerson.getName());//       一般一个人就一个职业        mSocial = (SocialRole) mDaoSession.getSocialRoleDao().queryBuilder().unique();        if (mSocial == null) {            System.out.println("xcqw mSocial == null");            SocialRole social = new SocialRole();            social.setJobDesc("法师");            social.setSalary(1000);            mDaoSession.getSocialRoleDao().insert(social);            mSocial = social;        }        System.out.println("xcqw social"+mSocial.getJobDesc());//        Person  跟  socialRole  关联起来!!!!!!!!111//        只需要关联socialRoleId        mPerson.setSocialRoleId(mSocial.getId());        mDaoSession.getPersonDao().insertOrReplace(mPerson);//        开始查person的里的socialRole        System.out.println("xcqw oneToone" + mPerson.getSocialRole().toString());

• 一对多
  一个人写个多篇文章
  @ToMany(referencedJoinProperty = “authorId”)
  然后把person中的id设置给article中的authorId就建立关系了

Article.java

@Entitypublic class Article {    @Id    private Long id;    private String content;    private Long authorId;    @Generated(hash = 2128110276)    public Article(Long id, String content, Long authorId) {        this.id = id;        this.content = content;        this.authorId = authorId;    }    @Generated(hash = 742516792)    public Article() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getContent() {        return this.content;    }    public void setContent(String content) {        this.content = content;    }    public Long getAuthorId() {        return this.authorId;    }    public void setAuthorId(Long authorId) {        this.authorId = authorId;    }    @Override    public String toString() {        return "Article{" +                "id=" + id +                ", content='" + content + '\'' +                ", authorId=" + authorId +                '}';    }}

初始化

 List<Article> articleList = mDaoSession.getArticleDao().queryBuilder().list();        if(articleList.size() >0) {            for (int i = 0; i < articleList.size(); i++) {                if (articleList.get(i).equals("我是第1个篇")) {                    firstArticle = true;                } else if (articleList.get(i).equals("我是第2个篇")) {                    secondArticle = true;                } else {                    firstArticle = false;                    secondArticle = false;                }            }        }        if (!firstArticle) {            articleOne = new Article();            articleOne.setContent("我是第1个篇");//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!建立关系            articleOne.setAuthorId(mPerson.getId());        }        if (!secondArticle) {            articleTwo = new Article();            articleTwo.setContent("我是第2个篇");//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!建立关系            articleTwo.setAuthorId(mPerson.getId());            mDaoSession.getArticleDao().insertInTx(articleOne,articleTwo);        }        System.out.println("xcqw oneToMany"+mPerson.getArticleList().get(1).toString());

• 多对多
  一个学生有多个老师，一个老师有多个学生

Student.java

@Entitypublic class Student {    @Id    private Long id;    private String name;    // 对多，@JoinEntity注解：entity 中间表；sourceProperty 实体属性；targetProperty 外链实体属性    @ToMany    @JoinEntity(            entity = JoinStudentToTeacher.class,            sourceProperty = "sId",            targetProperty = "tId"    )    private List<Teacher> teacherList;    /** Used to resolve relations */    @Keep    private transient com.rebase.greendao.entity.DaoSession daoSession;    /** Used for active entity operations. */    @Keep    private transient com.rebase.greendao.entity.StudentDao myDao;    @Keep    public Student(Long id, String name) {        this.id = id;        this.name = name;    }    @Keep    public Student() {    }    @Override    public String toString() {        return "Student{" +                "id=" + id +                ", name='" + name + '\'' +                ", teacherList=" + teacherList +                '}';    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getName() {        return this.name;    }    public void setName(String name) {        this.name = name;    }    /**     * To-many relationship, resolved on first access (and after reset).     * Changes to to-many relations are not persisted, make changes to the target entity.     */    @Keep    public List<Teacher> getTeacherList() {        if (teacherList == null) {            final com.rebase.greendao.entity.DaoSession daoSession = this.daoSession;            if (daoSession == null) {                throw new DaoException("Entity is detached from DAO context");            }            com.rebase.greendao.entity.TeacherDao targetDao = daoSession.getTeacherDao();            List<Teacher> teacherListNew = targetDao._queryStudent_TeacherList(id);            synchronized (this) {                if (teacherList == null) {                    teacherList = teacherListNew;                }            }        }        return teacherList;    }    /** Resets a to-many relationship, making the next get call to query for a fresh result. */    @Keep    public synchronized void resetTeacherList() {        teacherList = null;    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#delete(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void delete() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.delete(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#refresh(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void refresh() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.refresh(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#update(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void update() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.update(this);    }    /** called by internal mechanisms, do not call yourself. */    @Keep    public void __setDaoSession(com.rebase.greendao.entity.DaoSession daoSession) {        this.daoSession = daoSession;        myDao = daoSession != null ? daoSession.getStudentDao() : null;    }}

Teacher.java

@Entitypublic class Teacher {    @Id    private Long id;    private String name;    // 对多，@JoinEntity注解：entity 中间表；sourceProperty 实体属性；targetProperty 外链实体属性    @ToMany    @JoinEntity(            entity = JoinStudentToTeacher.class,            sourceProperty = "tId",            targetProperty = "sId"    )    private List<Student> studentList;    /** Used to resolve relations */    @Keep    private transient com.rebase.greendao.entity.DaoSession daoSession;    /** Used for active entity operations. */    @Keep    private transient com.rebase.greendao.entity.TeacherDao myDao;    @Keep    public Teacher(Long id, String name) {        this.id = id;        this.name = name;    }    @Keep    public Teacher() {    }    @Override    public String toString() {        return "Teacher{" +                "id=" + id +                ", name='" + name + '\'' +                ", studentList=" + studentList +                '}';    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getName() {        return this.name;    }    public void setName(String name) {        this.name = name;    }    /**     * To-many relationship, resolved on first access (and after reset).     * Changes to to-many relations are not persisted, make changes to the target entity.     */    @Keep    public List<Student> getStudentList() {        if (studentList == null) {            final com.rebase.greendao.entity.DaoSession daoSession = this.daoSession;            if (daoSession == null) {                throw new DaoException("Entity is detached from DAO context");            }            com.rebase.greendao.entity.StudentDao targetDao = daoSession.getStudentDao();            List<Student> studentListNew = targetDao._queryTeacher_StudentList(id);            synchronized (this) {                if (studentList == null) {                    studentList = studentListNew;                }            }        }        return studentList;    }    /** Resets a to-many relationship, making the next get call to query for a fresh result. */    @Keep    public synchronized void resetStudentList() {        studentList = null;    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#delete(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void delete() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.delete(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#refresh(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void refresh() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.refresh(this);    }    /**     * Convenient call for {@link org.greenrobot.greendao.AbstractDao#update(Object)}.     * Entity must attached to an entity context.     */    @Keep    public void update() {        if (myDao == null) {            throw new DaoException("Entity is detached from DAO context");        }        myDao.update(this);    }    /** called by internal mechanisms, do not call yourself. */    @Keep    public void __setDaoSession(com.rebase.greendao.entity.DaoSession daoSession) {        this.daoSession = daoSession;        myDao = daoSession != null ? daoSession.getTeacherDao() : null;    }}

初始化

List<Student> studentList = mDaoSession.getStudentDao().queryBuilder().list();        if (studentList.size() == 0) {            Student studentOne = new Student();            studentOne.setId(1l);            studentOne.setName("stu1");            Student studentTwo = new Student();            studentTwo.setId(2l);            studentTwo.setName("stu2");            Teacher teachOne = new Teacher();            teachOne.setId(1l);            teachOne.setName("tech1");            Teacher teachTwo = new Teacher();            teachTwo.setId(2l);            teachTwo.setName("tech2");            // 模拟 多对多关系          //Student1有teacher1 teacher2            JoinStudentToTeacher stOne = new JoinStudentToTeacher();            stOne.setSId(1l);            stOne.setTId(1l);            JoinStudentToTeacher stTwo = new JoinStudentToTeacher();            stTwo.setSId(1l);            stTwo.setTId(2l);            //teacher1 有stu1 stu2            JoinStudentToTeacher stThree = new JoinStudentToTeacher();            stThree.setSId(1l);            stThree.setTId(1l);            JoinStudentToTeacher stFour = new JoinStudentToTeacher();            stFour.setSId(2l);            stFour.setTId(1l);            mDaoSession.getJoinStudentToTeacherDao().insertOrReplaceInTx(stOne, stTwo, stThree, stFour);            mDaoSession.getStudentDao().insertOrReplaceInTx(studentOne, studentTwo);            mDaoSession.getTeacherDao().insertOrReplaceInTx(teachOne, teachTwo);        }//        List<Student> students = mDaoSession.getStudentDao().queryBuilder().list();//        for(int i = 0;i<students.size();i++){//            for(int j= 0;j<students.get(i).getTeacherList().size();j++){//                System.out.println("xcqw teacher i--"+i+"--j--"+j+students.get(i).getTeacherList().get(j).toString());//            }//        }        List<Teacher> teachers = mDaoSession.getTeacherDao().queryBuilder().list();        for(int i = 0;i<teachers.size();i++){            for(int j= 0;j<teachers.get(i).getStudentList().size();j++){                System.out.println("xcqw student i--"+i+"--j--"+j+teachers.get(i).getStudentList().get(j).toString());            }        }        System.out.println("xcqw asdsad");

注意！！！
mDaoSession.getTeacherDao().queryBuilder().list();如果在这个地方打断点，下属的students是null,只有走完两个for循环调用get方法才会有值

四.源码