1
2
3
4
5
6
分割线
嵌套练习
2
3
4
5
斜体
123
加粗
删除线
小标题
- 1
- 2
- 3
- 4
- 5
数字编码
- 1
- 2
- 3
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
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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);
}
}
