android基础--使用嵌入式关系型SQLite数据库存储数据

public class DBOpenHelper extends SQLiteOpenHelper {

public DBOpenHelper(Context context) {

super(context, "test.db", null, 2);

}

public void onCreate(SQLiteDatabase db) {//数据库第一次被创建时候调用

db.execSQL("create table person (personid integer primary key autoincrement ,name varchar(20))");

}

//数据库版本号改变的时候调用，软件升级修改数据库表结构的代码方到此处

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

db.execSQL("alter table person add phone varchar(12) null");

}

}

public void testCreateDB () throws Throwable{

DBOpenHelper dbOpenHelper = new DBOpenHelper(getContext());

dbOpenHelper.getWritableDatabase();//数据库文件test.db放的位置：<当前包>/databases

}

public class PersonService {
private DbOpenHelper dbOpenHelper;

public PersonService(Context context) {
dbOpenHelper = new DbOpenHelper(context);
}

public void save(Person p) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
String sql = "insert into person(name,phone) values(?,?)";
Object[] objs = new Object[] { p.getName(), p.getPhone() };
db.execSQL(sql, objs);
}

public void update(Person p) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
String sql = "update person set name = ?, phone = ? where personid = ?";
Object[] objs = new Object[] { p.getName(), p.getPhone(), p.getId() };
db.execSQL(sql, objs);
}

public void del(int id) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
String sql = "delete from person where personid = ?";
Object[] objs = new Object[] { id };
db.execSQL(sql, objs);
}

public Person find(int id) {
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
String sql = "select * from person where personid = ?";
String[] strs = { String.valueOf(id) };
Cursor cursor = db.rawQuery(sql, strs);
if (cursor.moveToFirst()) {
int personid = cursor.getInt(cursor.getColumnIndex("personid"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
cursor.close();
return new Person(personid, name, phone);
}
return null;
}

public List<Person> getScroll(int offset, int maxResult) {
List<Person> persons = new ArrayList<Person>();
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
String sql = "select * from person order by personid asc limit ?,?";
String[] strs = { String.valueOf(offset), String.valueOf(maxResult) };
Cursor cursor = db.rawQuery(sql,strs);
while(cursor.moveToNext()){
int personid = cursor.getInt(cursor.getColumnIndex("personid"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
persons.add(new Person(personid, name, phone));
}
cursor.close();
return persons;
}

public long getcount() {
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
String sql = "select count(*) from person";
Cursor cursor = db.rawQuery(sql, null);
cursor.moveToFirst();
return cursor.getLong(0);
}
}

public class DbTest extends AndroidTestCase{
public void testCreate()throws Throwable{
DbOpenHelper dbhelp = new DbOpenHelper(getContext());
dbhelp.getWritableDatabase();
}
public void testSave()throws Throwable{
PersonService service = new PersonService(getContext());
for(int i = 0;i<20;i++){
Person p = new Person("qq"+i, "100000"+i);
service.save(p);
}
}
public void testDel() throws Throwable{
PersonService service = new PersonService(getContext());
service.del(22);
}
public void testFidn()throws Throwable{
PersonService service = new PersonService(getContext());
Person p = service.find(2);
Log.i("find", p.getName()+p.getPhone());
}
public void testUpdate()throws Throwable{
PersonService service = new PersonService(getContext());
Person p = service.find(2);
p.setName("update");
p.setPhone("5432463653");
service.update(p);
}
public void testCount()throws Throwable{
PersonService service = new PersonService(getContext());
Log.i("count", service.getcount()+"");
}
public void testScrolldata() throws Throwable{
PersonService service = new PersonService(getContext());
List<Person> persons = service.getScroll(12, 8);
for(Person p : persons){
Log.i("Person", p.toString());
}
}
}

SQLiteDatabase db = dbOpenHelper.getWritableDatabase();

db.beginTransaction();
try{
db.execSQL("update person set amount=amount-10 where personid=1");
db.execSQL("update person set amount=amount+10 where personid=2");
db.setTransactionSuccessful();
}finally{
//事务标志的默认值为false
db.endTransaction();//提交、回滚，由事务标志决定，如果事务标志为True(成功)，提交,否则回滚
}