Store multiple data into one primary ID in mysql (audit trail) - php

Question

I thought i was in the right track. I forgot that a user can do multiple activities. What I did was it's only one activity. What can i do with this? I came up with a solution that might work, come up with an sql statement that updates the activity column without overwriting the text. But that seems stupid. Pretty sure theres a better solution?

Answer 1

I made some adjustment but I think this will improve your database. See this in action via http://sqlfiddle.com/#!2/c6546/9/0
CREATE TABLE workers
(
id_workers int primary key,
username varchar(30),
type varchar(30)
);
CREATE TABLE activities
(
id_activities int auto_increment primary key,
activity varchar(30)
);
CREATE TABLE timesheet
(
id_timesheet int auto_increment primary key,
id_workers int,
id_activities int,
start_time datetime,
end_time datetime
);
INSERT INTO workers
(id_workers, username, type)
VALUES
('1','Danice', 'Administrator'),
('2','Micheal', 'Administrator');
INSERT INTO activities
(activity)
VALUES
('Edit Employee'),
('Edit Employee Information'),
('Edit Department');
INSERT INTO timesheet
(id_workers, id_activities,start_time, end_time)
VALUES
('1', '1', '2013-03-14 13:15:00','2013-03-14 13:20:00'),
('2', '2', '2013-03-14 13:00:00','2013-03-14 14:00:00'),
('1', '2', '2013-03-14 13:21:00','2013-03-14 13:23:00'),
('1', '3', '2013-03-14 13:24:00','2013-03-14 13:45:00');
SELECT a.id_activities, w.username, w.type, a.activity, t.start_time, t.end_time
FROM (timesheet AS t LEFT JOIN activities AS a ON t.id_activities = a.id_activities ) LEFT JOIN workers AS w ON t.id_workers = w.id_workers;
BTW you could use MYSQL workbench if you want to get a good overview from you database layout. Set up a schema inside workbench for reference when coding. Or just use pen and paper. ;-)
With regard to you audit trail, you could give workers the option to delete there activity from the timesheet by adding and extra column (e.g. audittrail) to timesheet. By default the column audittrail is set to 0 and if an worker deletes his entry you give this column the value 1. Then add to you SELECT query "WHERE audittrail = 0" to display all the timesheet entries. And in the case you require an audit trail you leave out the WHERE clause.

Answer 2

http://www.c-sharpcorner.com/uploadfile/nipuntomar/normalization-and-its-types/
What you're trying to do is called database normalization. You want meta data against one particular record. So just 'glancing' at your problem. Make a table for storage, X, and a have a foreign key constraint to the data record you want to describe. In this case, it looks like the users table, and then have fields in this X table which stores the 'multiple data' type which is related to users table.
Tables
users -- table
id
username
password
status
updation_date
creation_date
x -- table
id
users_id -- foreign key constraint
part1_of_multiple_data -- meta log data you are wanting
part2_of_multiple_data -- meta log data you are wanting
part3_of_multiple_data -- add more fields as you need in the table.
updation_date
creation_date