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How can I implement model revisions in Laravel?

Posted by: admin November 30, 2017 Leave a comment

Questions:

This question is for my pastebin app written in PHP.

I did a bit of a research, although I wasn’t able to find a solution that matches my needs. I have a table with this structure:

+-----------+------------------+------+-----+---------+----------------+
| Field     | Type             | Null | Key | Default | Extra          |
+-----------+------------------+------+-----+---------+----------------+
| id        | int(12) unsigned | NO   | PRI | NULL    | auto_increment |
| author    | varchar(50)      | YES  |     |         |                |
| authorid  | int(12) unsigned | YES  |     | NULL    |                |
| project   | varchar(50)      | YES  |     |         |                |
| timestamp | int(11) unsigned | NO   |     | NULL    |                |
| expire    | int(11) unsigned | NO   |     | NULL    |                |
| title     | varchar(25)      | YES  |     |         |                |
| data      | longtext         | NO   |     | NULL    |                |
| language  | varchar(50)      | NO   |     | php     |                |
| password  | varchar(60)      | NO   |     | NULL    |                |
| salt      | varchar(5)       | NO   |     | NULL    |                |
| private   | tinyint(1)       | NO   |     | 0       |                |
| hash      | varchar(12)      | NO   |     | NULL    |                |
| ip        | varchar(50)      | NO   |     | NULL    |                |
| urlkey    | varchar(8)       | YES  | MUL |         |                |
| hits      | int(11)          | NO   |     | 0       |                |
+-----------+------------------+------+-----+---------+----------------+

This is for a pastebin application. I basically want paste revisions so that if you open paste #1234, it shows all past revisions of that paste.

I thought of three ways:

Method 1

Have a revisions table with id and old_id or something and for each ID, I would insert all old revisions, so if my structure looks like this:

rev3: 1234
rev2: 1233
rev1: 1232

The table will contain this data:

+-------+----------+
| id    | old_id   |
+-------+----------+
| 1234  | 1233     |
| 1234  | 1232     |
| 1233  | 1232     |
+-------+----------+

The problem which I have with this is that it introduces a lot of duplicate data. And the more the revisions get, it has not only more data but I need to do N inserts for each new paste to the revisions table which is not great for a large N.

Method 2

I can add a child_id to the paste table at the top and just update that. And then, when fetching the paste, I will keep querying the db for each child_id and their child_id and so on… But the problem is, that will introduce too many DB reads each time a paste with many revisions is opened.

Method 3

Also involves a separate revisions table, but for the same scenario as method 1, it will store the data like this:

+-------+-----------------+
| id    | old_id          |
+-------+-----------------+
| 1234  | 1233,1232       |
| 1233  | 1232            |
+-------+-----------------+

And when someone opens paste 1234, I’ll use an IN clause to fetch all child paste data there.

Which is the best approach? Or is there a better approach? I am using Laravel 4 framework that has Eloquent ORM.

EDIT: Can I do method 1 with a oneToMany relationship? I understand that I can use Eager Loading to fetch all the revisions, but how can I insert them without having to do a dirty hack?

EDIT: I figured out how to handle the above. I’ll add an answer to close this question.

Answers:

If you are on Laravel 4, give Revisionable a try. This might suite your needs

Questions:
Answers:

So here is what I am doing:

Say this is the revision flow:

1232 -> 1233 -> 1234
1232 -> 1235

So here is what my revision table will look like:

+----+--------+--------+
| id | new_id | old_id |
+----+--------+--------+
| 1  | 1233   | 1232   |
| 2  | 1234   | 1233   |
| 3  | 1234   | 1232   |
| 4  | 1235   | 1232   |
+----+--------+--------+

IDs 2 and 3 show that when I open 1234, it should show both 1233 and 1232 as revisions on the list.

Now the implementation bit: I will have the Paste model have a one to many relationship with the Revision model.

  • When I create a new revision for an existing paste, I will run a batch insert to add not only the current new_id and old_id pair, but pair the current new_id with all revisions that were associated with old_id.
  • When I open a paste – which I will do by querying new_id, I will essentially get all associated rows in the revisions table (using a function in the Paste model that defines hasMany(‘Revision’, ‘new_id’)) and will display to the user.

I am also thinking about displaying the author of each revision in the “Revision history” section on the “view paste” page, so I think I’ll also add an author column to the revision table so that I don’t need to go back and query the main paste table to get the author.

So that’s about it!

Questions:
Answers:

There are some great packages to help you keeping model revisions:

  • If you only want to keep the models revisions you can use:

Revisionable

  • If you also want to log any other actions, whenever you want, with custom data, you can use:

Laravel Activity Logger

Honorable mentions: