数据库增删改查

//数据库 增删改查

public class UserDao {

private SQLiteDatabase db;
private static final String TABLE_NAME = "user";


public UserDao(Context context) {


Second second = new Second(context);
db = second.getWritableDatabase();


}


public boolean add(String name, String pwd) {


ContentValues values = new ContentValues();
values.put("name", name);
values.put("pwd", pwd);


long result = db.insert(TABLE_NAME, null, values);
if (result != -1) {


return true;


} else {


return false;
}


}


public ArrayList<Userdata> selectall() {
ArrayList<Userdata> list = new ArrayList<Userdata>();
Cursor cursor = db.query(false, TABLE_NAME, null, null, null, null,
null, null, null);
while (cursor.moveToNext()) {

String name=cursor.getString(cursor.getColumnIndex("name"));
String pwd=cursor.getString(cursor.getColumnIndex("pwd"));
int id=cursor.getInt(cursor.getColumnIndex("_id"));

Userdata userdata=new Userdata();
userdata.setId(id);
userdata.setName(name);
userdata.setPwd(pwd);
list.add(userdata);

}

return list;


}

public boolean delete(int id){

int result = db.delete(TABLE_NAME, "_id=?", new String[]{String.valueOf(id)});
if (result>0) {
return true;


}else {


return false;
}


}

public boolean update(String name,String pwd,int id){

ContentValues values=new ContentValues();
values.put("name", name);
values.put("pwd", pwd);
values.put("_id", id);


int result = db.update(TABLE_NAME, values, "_id=?", new String[]{String.valueOf(id)});
if (result>0) {

return true;

}else {

return false;

}
}


}