androidSQlite数据库

// 通过SQLiteOpenHelper调用如下方法时会返回SQLiteDatabase&＃xff0c;通过SQLiteDatabase可以对数据库进行操作
getWritableDatabase()
getReadableDatabase()

public class PersonService {private DBOpenHelper dbOpenHelper;public PersonService(Context context) {this.dbOpenHelper &＃61; new DBOpenHelper(context);}public void payment(){ 通过SQLiteOpenHelper调用如下方法时会返回SQLiteDatabase&＃xff0c;通过SQLiteDatabase可以对数据库进行操作SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();db.beginTransaction();//开启事务try{db.execSQL("update person set amount&＃61;amount-10 where personid&＃61;1");db.execSQL("update person set amount&＃61;amount&＃43;10 where personid&＃61;2");db.setTransactionSuccessful();//设置事务的标志为True}finally{db.endTransaction();//结束事务,有两种情况&＃xff1a;commit,rollback,//事务的提交或回滚是由事务的标志决定的,如果事务的标志为True&＃xff0c;事务就会提交&＃xff0c;否侧回滚,默认情况下事务的标志为False
}}/*** 添加记录* &＃64;param person*/public void save(Person person){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();db.execSQL("insert into person(name, phone, amount) values(?,?,?)",new Object[]{person.getName(), person.getPhone(), person.getAmount()});}/*** 删除记录* &＃64;param id 记录ID*/public void delete(Integer id){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();db.execSQL("delete from person where personid&＃61;?", new Object[]{id});}/*** 更新记录* &＃64;param person*/public void update(Person person){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();db.execSQL("update person set name&＃61;?,phone&＃61;?,amount&＃61;? where personid&＃61;?",new Object[]{person.getName(), person.getPhone(), person.getAmount(), person.getId()});}/*** 查询记录* &＃64;param id 记录ID* &＃64;return*/public Person find(Integer id){SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.rawQuery("select * from person where personid&＃61;?", new String[]{id.toString()});if(cursor.moveToFirst()){int personid &＃61; cursor.getInt(cursor.getColumnIndex("personid"));int amount &＃61; cursor.getInt(cursor.getColumnIndex("amount"));String name &＃61; cursor.getString(cursor.getColumnIndex("name"));String phone &＃61; cursor.getString(cursor.getColumnIndex("phone"));return new Person(personid, name, phone, amount);}cursor.close();return null;}/*** 分页获取记录* &＃64;param offset 跳过前面多少条记录* &＃64;param maxResult 每页获取多少条记录* &＃64;return*/public List getScrollData(int offset, int maxResult){List persons &＃61; new ArrayList();SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.rawQuery("select * from person order by personid asc limit ?,?",new String[]{String.valueOf(offset), String.valueOf(maxResult)});while(cursor.moveToNext()){int personid &＃61; cursor.getInt(cursor.getColumnIndex("personid"));int amount &＃61; cursor.getInt(cursor.getColumnIndex("amount"));String name &＃61; cursor.getString(cursor.getColumnIndex("name"));String phone &＃61; cursor.getString(cursor.getColumnIndex("phone"));persons.add(new Person(personid, name, phone, amount));}cursor.close();return persons;}/*** 分页获取记录* &＃64;param offset 跳过前面多少条记录* &＃64;param maxResult 每页获取多少条记录* &＃64;return*/public Cursor getCursorScrollData(int offset, int maxResult){SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.rawQuery("select personid as _id,name,phone,amount from person order by personid asc limit ?,?",new String[]{String.valueOf(offset), String.valueOf(maxResult)});return cursor;}/*** 获取记录总数* &＃64;return*/public long getCount(){SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.rawQuery("select count(*) from person", null);cursor.moveToFirst();long result &＃61; cursor.getLong(0);cursor.close();return result;}
}

public class OtherPersonService {private DBOpenHelper dbOpenHelper;public OtherPersonService(Context context) {this.dbOpenHelper &＃61; new DBOpenHelper(context);}/*** 添加记录* &＃64;param person*/public void save(Person person){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();ContentValues values &＃61; new ContentValues();values.put("name", person.getName());values.put("phone", person.getPhone());values.put("amount", person.getAmount());db.insert("person", null, values);}/*** 删除记录* &＃64;param id 记录ID*/public void delete(Integer id){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();db.delete("person", "personid&＃61;?", new String[]{id.toString()});}/*** 更新记录* &＃64;param person*/public void update(Person person){SQLiteDatabase db &＃61; dbOpenHelper.getWritableDatabase();ContentValues values &＃61; new ContentValues();values.put("name", person.getName());values.put("phone", person.getPhone());values.put("amount", person.getAmount());db.update("person", values, "personid&＃61;?", new String[]{person.getId().toString()});}/*** 查询记录* &＃64;param id 记录ID* &＃64;return*/public Person find(Integer id){SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.query("person", null, "personid&＃61;?", new String[]{id.toString()}, null, null, null);if(cursor.moveToFirst()){int personid &＃61; cursor.getInt(cursor.getColumnIndex("personid"));int amount &＃61; cursor.getInt(cursor.getColumnIndex("amount"));String name &＃61; cursor.getString(cursor.getColumnIndex("name"));String phone &＃61; cursor.getString(cursor.getColumnIndex("phone"));return new Person(personid, name, phone, amount);}cursor.close();return null;}/*** 分页获取记录* &＃64;param offset 跳过前面多少条记录* &＃64;param maxResult 每页获取多少条记录* &＃64;return*/public List getScrollData(int offset, int maxResult){List persons &＃61; new ArrayList();SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.query("person", null, null, null, null, null, "personid asc", offset&＃43; ","&＃43; maxResult);while(cursor.moveToNext()){int personid &＃61; cursor.getInt(cursor.getColumnIndex("personid"));int amount &＃61; cursor.getInt(cursor.getColumnIndex("amount"));String name &＃61; cursor.getString(cursor.getColumnIndex("name"));String phone &＃61; cursor.getString(cursor.getColumnIndex("phone"));persons.add(new Person(personid, name, phone, amount));}cursor.close();return persons;}/*** 获取记录总数* &＃64;return*/public long getCount(){SQLiteDatabase db &＃61; dbOpenHelper.getReadableDatabase();Cursor cursor &＃61; db.query("person", new String[]{"count(*)"}, null, null, null, null, null);cursor.moveToFirst();long result &＃61; cursor.getLong(0);cursor.close();return result;}
}