上一篇 总结了grendao 环境搭建以及简单的增删查改,接下来将全面解析框架的使用,基于上篇的orm模型(Note)数据库讲解
GreenDao的插入:
插入的方式有很多:
1:daoSession.getNoteDao().insert(note);
//插入note 如果note指定主键与表中已经存在了,就会发生异常(android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: tb_note._id (code 1555))而插入不进去
daoSession.insert(note); 同上
2: daoSession.getNoteDao().insertOrReplace(note);
当主键存在的时候会替换,所以能够很好的执行插入操作,推荐
daoSession.insertOrReplace(note); 同上
3: 原生的sqlite
String insertSql = String.format("insert into %s (%s,%s,%s) values('%s','%s','%s')", NoteDao.TABLENAME, NoteDao.Properties.Title.columnName, NoteDao.Properties.Content.columnName, NoteDao.Properties.CreateTime.columnName, note.getTitle(), note.getContent(), note.getCreateTime()); daoSession.getDatabase().execSQL(insertSql);
4:批量插入
public void insertBatch(Listnotes){
daoSession.getNoteDao().insertInTx(notes);
}
GreenDao的更新操作
1:单条更新(唯一性条件是主键相同)
public void update(Note note) throws Exception { daoSession.update(note); // daoSession.getNoteDao().update(note); }
2:批量更新
//批量更新 public void updateBatch(Listnotes) throws Exception { daoSession.getNoteDao().updateInTx(notes); }
3:原生sql:
public void updateSql(String sql){
// daoSession.getDatabase().execSQL("update .....");
daoSession.getDatabase().execSQL(sql);
}
GreenDao 的删除操作
1:单条删除(唯一性是主见相同)
public void delete(Note note) throws Exception {
daoSession.delete(note); // daoSession.getNoteDao().delete(note); }
2: 单条删除 指定主键删除
public void delete(long id) { daoSession.getNoteDao().deleteByKey(id); }
3:批量删除
public void deleteBatch(List4:批量按主键删除notes) { daoSession.getNoteDao().deleteInTx(notes); }
// 批量按主键删除 public void deleteBatchByKey(ListpkIds) { daoSession.getNoteDao().deleteByKeyInTx(pkIds); }
5:删除所有
public void deleteAll() throws Exception { daoSession.deleteAll(Note.class); // daoSession.getNoteDao().deleteAll(); }
6:原始sqlite语句
daoSession.getDatabase().execSQL(deletesql);
GreenDao 查询操作 也是最复杂的
1:单条查询
//按主键查询
public Note query(long pk) throws Exception {
// daoSession.getNoteDao().load(pk);//按主见查询
//daoSession.getNoteDao().load(rowId);//按行号查询
return daoSession.load(Note.class, pk);
}
public List queryBuider() throws Exception {
//select from tb_note where Content like 'greendao'
return daoSession.getNoteDao().queryBuilder().where(NoteDao.Properties.Content.like("greendao")).build().list();
}
public long queryBuider2(long pk) throws Exception {
//select count(*) from tb_note where Content like 'greendao'
return daoSession.getNoteDao().queryBuilder().where(NoteDao.Properties.Content.like("greendao")).buildCount().count();
}
public void queryBuider3() throws Exception {
Cursor cursor = null;
try {
//CursorQuery 部分查询
CursorQuery greendao = daoSession.getNoteDao().queryBuilder().where(NoteDao.Properties.Content.like("greendao")).buildCursor();
cursor = greendao.query();
while (cursor.moveToNext()) {
long id = cursor.getInt(0);
String title = cursor.getString(1);
String content = cursor.getString(2);
String time = cursor.getString(cursor.getColumnIndex(NoteDao.Properties.CreateTime.columnName));
}
} finally {
if (cursor != null)
cursor.close();
}
}
3:查询所有:
public void queryAll()
{
daoSession.loadAll(Note.class);
daoSession.queryBuilder(Note.class).build().list();
daoSession.getNoteDao().queryBuilder().build().list();
daoSession.getNoteDao().loadAll();
}