SQLite用sql语句进行增删改查

用sql语句实现数据库的基本增删改查操作

public class SqliteActivity extends Activity {

    MySqliteOpenHelper helper = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sqlite);
        helper = new MySqliteOpenHelper(this, "mengk.db", null, 5);
    }

    public void createDb(View view) {
//      MySqliteOpenHelper helper = new MySqliteOpenHelper(this, "mengk.db", null, 1);
        MySqliteOpenHelper helper = new MySqliteOpenHelper(this, "mengk.db", null, 5);
        helper.getWritableDatabase();
    }


    /**
     * 增加一条数据
     * @param view
     */
    public void add(View view) {
        SQLiteDatabase db = helper.getWritableDatabase();
        String sql = "insert into info(name,phone) values(?,?)";
        String name = "mengk";
        String phone = "17777777777";
        db.execSQL(sql,new Object[]{name,phone});
        db.close();
    }
    
    /**
     * 删除数据
     * @param view
     */
    public void delete(View view) {
        SQLiteDatabase db = helper.getWritableDatabase();
        db.execSQL("delete from info where name=?", new Object[]{"mengk"});
        db.close();
    }
    
    /**
     * 更新数据
     * @param view
     */
    public void update(View view) {
        String sql = "update info set phone=? where name=?";
        String name = "mengk";
        String phone = "18888888888";
        SQLiteDatabase db = helper.getWritableDatabase();
        db.execSQL(sql, new Object[]{phone,name});
        db.close();
        
    }
    
    /**
     * 查询数据
     * @param view
     */
    public void query(View view) {
        String sql = "select * from info";
        SQLiteDatabase db = helper.getWritableDatabase();
        Cursor cursor = db.rawQuery(sql, null);
        if (cursor != null && cursor.getColumnCount() > 0) {
            while (cursor.moveToNext()) {
                String name = cursor.getString(1);
                String phone = cursor.getString(2);
                System.out.println("name:"+name+"----"+phone);
            }
            cursor.close();
        }
        db.close();
        
    }

}