Andy introduces ORMLite, an ORM library for Android. He demonstrates how to define data models with annotations, create database helpers to manage the underlying SQLite database, and implement DAO classes to perform CRUD operations and transactions on the data models. The code examples show how to define one-to-many relationships between User and Group data tables, and use the ORMLite API to easily insert, query, update, and delete records while handling transactions and relationships between the tables.

1. ORMLite Android
by andyang

2. About me
• 哲偉、Andy 、⼩小⽺羊
• Android Code Club
• Every Wed. 19:00 - 22:00 果⼦子咖啡
• Android third-party gitbook
• Join us
• Android Developer

3. 為何我今天在這

4. 聖亞：我報名這次的主題了
我：很好啊
聖亞：我順便幫你報了
OS：WTF
我：！！！

5. 就這樣被推坑了，參加讀書會好處多多
可練就⼀一⾝身隨時被推坑的技能

7. 豪華ORM就此誕⽣生
彥彬表⽰示....

8. 有⼈人沒有使⽤用過ORM嗎？

9. 有何不同？

10. 進⼊入正題
使⽤用 ORMLite
製作⼀一對多資料關聯

11. Data Table User
@DatabaseTable(tableName = "User")
public class User {
@DatabaseField(generatedId = true)
private int id;
@DatabaseField
private String name;
@DatabaseField
private int sort;
@ForeignCollectionField
private ForeignCollection<Group> groups;
public User() {}
}

12. Data Table Group
@DatabaseTable(tableName = "Group")
public class Group {
@DatabaseField(generatedId = true)
private int id;
@DatabaseField
private String name;
@DatabaseField
private String description;
@DatabaseField(foreign = true, foreignAutoRefresh =
true, canBeNull = false, columnName = "user_id")
private User user;
public Group() {}
}

13. public class DatabaseHelper extends OrmLiteSqliteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "Demo";
private static DatabaseHelper instance;
private DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public static synchronized DatabaseHelper getHelper(Context context) {
context = context.getApplicationContext();
if (instance == null) {
synchronized (DatabaseHelper.class) {
if (instance == null)
instance = new DatabaseHelper(context);
}
}
return instance;
}
}
DatabaseHelper

14. onCreate & onUpdate
@Override
public void onUpgrade(SQLiteDatabase database, ConnectionSource
connectionSource, int oldVersion, int newVersion) {
try {
TableUtils.dropTable(connectionSource, User.class, true);
TableUtils.dropTable(connectionSource, Group.class, true);
onCreate(database, connectionSource);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onCreate(SQLiteDatabase database, ConnectionSource
connectionSource) {
try {
TableUtils.createTable(connectionSource, User.class);
TableUtils.createTable(connectionSource, Group.class);
} catch (SQLException e) {
e.printStackTrace();
}
}

15. Abstract Base Dao
public abstract class BaseDao<T, ID> {
private Dao<T, ID> dao;
private DatabaseHelper helper;
public BaseDao(Context context, Class<T> clazz) {
try {
helper = DatabaseHelper.getHelper(context);
dao = helper.getDao(clazz);
} catch (SQLException e) {
e.printStackTrace();
}
}
public Dao<T, ID> getDao() {
return dao;
}
}

16. CRUD
public int insert(T item) {
int id;
try {
id = dao.create(item);
} catch (SQLException e) {
e.printStackTrace();
id = -1;
}
return id;
}
public int deleteById(ID primaryKey) {
int id;
try {
id = dao.deleteById(primaryKey);
} catch (SQLException e) {
e.printStackTrace();
id = -1;
}
return id;
}
public int update(T item) {
int id;
try {
id = dao.update(item);
} catch (SQLException e) {
e.printStackTrace();
id = -1;
}
return id;
}
public T getById(ID id) {
try {
return dao.queryForId(id);
} catch (SQLException e) {
e.printStackTrace();
return null;
}
}

17. getAll, max, minpublic List<T> getAll() {
try {
return dao.queryBuilder().orderBy("id", false).query();
} catch (SQLException e) {
e.printStackTrace();
return Collections.emptyList();
}
}
public List<T> getAll(boolean isAsc) {
try {
return dao.queryBuilder().orderBy("id", isAsc).query();
} catch (SQLException e) {
e.printStackTrace();
return Collections.emptyList();
}
}
public List<T> getAll(String field, boolean isAsc) {
try {
return dao.queryBuilder().orderBy(field, isAsc).query();
} catch (SQLException e) {
e.printStackTrace();
return Collections.emptyList();
}
}
public T maxOfFieldItem(String field) throws Exception {
return dao.queryBuilder().orderBy(field, false).limit(1L).query().get(0);
}
public T minOfFieldItem(String field) throws Exception {
return dao.queryBuilder().orderBy(field, true).limit(1L).query().get(0);
}

18. Transaction
public void insertWithTransaction(final List<T> items) {
try {
TransactionManager.callInTransaction(helper.getConnectionSource(),
new Callable<Void>() {
@Override
public Void call() throws Exception {
for (T t : items) {
dao.create(t);
}
return null;
}
});
} catch (SQLException e) {
e.printStackTrace();
}
}

19. Custom Dao
public class UserDao extends BaseDao<User, Integer>{
public UserDao(Context context) {
super(context, User.class);
}
public void swap(int sourceId, int targetId) {
int sourceSort = getById(sourceId).getSort();
int targetSort = getById(targetId).getSort();
update(getById(sourceId).setSort(targetSort));
update(getById(targetId).setSort(sourceSort));
}
@Override
public int insert(User item) {
try {
item.setSort(maxOfFieldItem("sort").getSort() + 1);
}catch (Exception e){
item.setSort(1);
e.printStackTrace();
}
return super.insert(item);
}
}

20. Github ORMLiteDemo

21. DEMO