1

2

3

4

5

6

分割线

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嵌套练习

2

3

4

5

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斜体

123
加粗
删除线

小标题

• 1
• 2
• 3

• 4

• 5

数字编码

1. 1
2. 2
3. 3

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表格

Tables	Are	Cool
col 3 is	right-aligned	$1600
col 2 is	centered	$12
zebra stripes	are neat	$1

图片测试

测试图片 上一曲图标

代码测试

public class DataBaseAdapter {
    MyDatabasesHelper db;

    public DataBaseAdapter(Context context) {
        db = new MyDatabasesHelper(context);
    }

    //增加数据操作
    public void add(Emp e) {
        SQLiteDatabase sq = db.getWritableDatabase();   //获取数据库写权限
        ContentValues values = new ContentValues();
        values.put(MyDatabasesHelper.NAME, e.getName());
        values.put(MyDatabasesHelper.AGE, e.getAge());
        values.put(MyDatabasesHelper.SEX, e.getSex());
        values.put(MyDatabasesHelper.SALARY, e.getSalary());
        sq.insertOrThrow(MyDatabasesHelper.TAB_NAME, null, values);
//        sq.execSQL("INSERT INTO emp(name,age,sex)VALUES(\'"+e.getName()+"\',"+e.getAge()+",\'"+e.getSex()+"\'"+")");
        Log.i("add", e.toString());
    }

    //修改数据操作
    public void update(Emp e) {
        SQLiteDatabase sq = db.getWritableDatabase();   //获取数据库写权限
        ContentValues values = new ContentValues();
        values.put(MyDatabasesHelper.NAME, e.getName());
        values.put(MyDatabasesHelper.AGE, e.getAge());
        values.put(MyDatabasesHelper.SEX, e.getSex());
        values.put(MyDatabasesHelper.SALARY, e.getSalary());
        sq.update(db.TAB_NAME, values, MyDatabasesHelper.ID + "=?", new String[]{String.valueOf(e.getId())});
        db.close();
    }

    //删除数据操作
    public void delete(int id) {
        SQLiteDatabase sq = db.getWritableDatabase();   //获取数据库写权限
        sq.delete(MyDatabasesHelper.TAB_NAME, "id=?", new String[]{String.valueOf(id)});
    }

    //查询单个数据操作
    public Emp find(int id) {
        Emp emp = null;
        SQLiteDatabase sq = db.getReadableDatabase();   //获取数据库写权限
        String table = MyDatabasesHelper.TAB_NAME;
        String[] columns = new String[]{MyDatabasesHelper.ID,
                MyDatabasesHelper.NAME,
                MyDatabasesHelper.SEX,
                MyDatabasesHelper.AGE,
                MyDatabasesHelper.SALARY};
        Cursor result = sq.query(table
                , columns
                , "id=?", new String[]{String.valueOf(id)}
                , null, null, null);
        while (result.moveToNext()) {
            emp = new Emp();
            emp.setId(result.getInt(0));
            emp.setName(result.getString(1));
            emp.setAge(result.getInt(2));
            emp.setSalary(result.getDouble(3));
        }

        return emp;
    }

    //查询所有数据操作
    public List<Emp> findAll() {
        List<Emp> list = new ArrayList<>();
        SQLiteDatabase sq = db.getReadableDatabase();   //获取数据库写权限
        String table = MyDatabasesHelper.TAB_NAME;
        String[] columns = new String[]{MyDatabasesHelper.ID, MyDatabasesHelper.NAME, MyDatabasesHelper.AGE, MyDatabasesHelper.SEX, MyDatabasesHelper.SALARY};

        Cursor result = sq.query(table, columns, null, null, null, null, null);

        while (result.moveToNext()) {
            Emp emp = new Emp();
            emp.setId(result.getInt(0));
            emp.setName(result.getString(1));
            emp.setAge(result.getInt(2));
            emp.setSex(result.getString(3));
            emp.setSalary(result.getDouble(4));
            Log.i("tag", emp.toString());
            list.add(emp);
        }

        return list;
    }

    //删除数据库
    public void dropTable() {
        SQLiteDatabase sq = db.getWritableDatabase();
        sq.execSQL("drop table emp");
    }

    //创建数据表
    public void createTable() {
        SQLiteDatabase sq = db.getWritableDatabase();
        sq.execSQL(MyDatabasesHelper.CREATE_TABLE);
    }
}