Web architecture - how to save and restore DB snapshot efficiently - php

I need some advices on the best way to create/save/restore database snapshots for a website backend.
Here are the technical details (but I guess answers can be API independant) :
PHP : 5.3
PHP framework : Kohana 3.*
DB : MySQL 5.1
My webapp can be compared to a simple stock managment tool. The DB contains products with prices. At some point, users perform actions on these products (eg an order). At this moment, a PARTIAL snapshot of the DB is produced with only the related items. Later, in the main DB, products may be deleted or their price might change.
My goal is to store these snapshots, then, later, restore them using the code written for the full DB, to minimize code development and complexity.
As my DB is originally in MySQL, I plan to dump parts of the DB in a text file and zip it. To restore it, unzip, and reinject it in another DB (to not override items with the same names whose attributes have changed).
Is this an correct way to create and store parts of a DB? Or do smart designs handle that more efficiently?
Kohana specific : How to deal with ORM and multiple DB connections ? Objects are bound to only one DB. The default DB conection seems to be specfied in the session. Unfortunatelly, only one session seems to be allow at a time...
Thanks!

Have a look at Minion task migrations https://github.com/kohana-minion/tasks-migrations

Related

Integrate prestashop database with local database

I was looking around and couldn't find an answer for this question. If however, it is duplicated in some way, I apologise.
My problem is: I have a physical store, which has a accounting program with some database where my products are. I now created a store with prestashop and wanted to synchronise both of them.
I want to be able to add a REF to my prestashop and take every field from my LOCAL DB (except images and descriptions); I also want to synchronise the STOCKS in "real time".
My idea is having a "middle DB" which takes requests and updates the other 2 DB, as such:
Prestashop DB <-> MIDDLE DB <-> Local DB
My middle DB would have the REFs and Quantities for all the products and check if the latter field is changed in either DB, let's say every 2 mins, to then update the database that did NOT perform the request.
How difficult is it to do this? How can I connect to both databases, using python, c# or c++ and perform such tasks?
I'm using prestashop 1.6. and I have access to my database via PHPmyAdmin.
Thank you!

How to merge local and live databases?

We've been developing for Wordpress for several years and whilst our workflow has been upgraded at several points there's one thing that we've never solved... merging a local Wordpress database with a live database.
So I'm talking about having a local version of the site where files and data are changed, whilst the data on the live site is also changing at the same time.
All I can find is the perfect world scenario of pulling the site down, nobody (even customers) touching the live site, then pushing the local site back up. I.e copying one thing over the other.
How can this be done without running a tonne of mysql commands? (it feels like they could fall over if they're not properly checked!) Can this be done via Gulp's (I've seen it mentioned) or a plugin?
Just to be clear, I'm not talking about pushing/pulling data back and forth via something like WP Migrate DB Pro, BackupBuddy or anything similar - this is a merge, not replacing one database with another.
I would love to know how other developers get around this!
File changes are fairly simple to get around, it's when there's data changes that it causes the nightmare.
WP Stagecoach does do a merge but you can't work locally, it creates a staging site from the live site that you're supposed to work on. The merge works great but it's a killer blow not to be able to work locally.
I've also been told by the developers that datahawk.io will do what I want but there's no release date on that.
It sounds like VersionPress might do what you need:
VersionPress staging
A couple of caveats: I haven't used it, so can't vouch for its effectiveness; and it's currently in early access.
Important : Take a backup of Live database before merging Local data to it.
Follow these steps might help in migrating the large percentage of data and merging it to live
Go to wp back-end of Local site Tools->Export.
Select All content radio button (if not selected by default).
This will bring an Xml file containing all the local data comprised of all default post types and custom post types.
Open this XML file in notepad++ or any editor and find and replace the Local URL with the Live URL.
Now visit the Live site and Import the XML under Tools->Import.
Upload the files (images) manually.
This will bring a large percentage of data from Local to Live .
Rest of the data you will have to write custom scripts.
Risk factors are :
When uploading the images from Local to Live , images of same name
will be overriden.
Wordpress saves the images in post_meta generating a serialized data for the images , than should be taken care of when uploading the database.
Serialized data in post_meta for post_type="attachment" saves serialized data for 3 or 4 dimensions of the images.
Usernames or email ids of users when importing the data , can be same (Or wp performs the function of checking unique usernames and emails) then those users will not be imported (might be possible).
If I were you I'd do the following (slow but affords you the greatest chance of success)
First off, set up a third database somewhere. Cloud services would probably be ideal, since you could get a powerful server with an SSD for a couple of hours. You'll need that horsepower.
Second, we're going to mysqldump the first DB and pipe the output into our cloud DB.
mysqldump -u user -ppassword dbname | mysql -u root -ppass -h somecloud.db.internet
Now we have a full copy of DB #1. If your cloud supports snapshotting data, be sure to take one now.
The last step is to write a PHP script that, slowly but surely, selects the data from the second DB and writes it to the third. We want to do this one record at a time. Why? Well, we need to maintain the relationships between records. So let's take comments and posts. When we pull post #1 from DB #2 it won't be able to keep record #1 because DB #1 already had one. So now post #1 becomes post #132. That means that all the comments for post #1 now need to be written as belonging to post #132. You'll also have to pull the records for the users who made those posts, because their user IDs will also change.
There's no easy fix for this but the WP structure isn't terribly complex. Building a simple loop to pull the data and translate it shouldn't be more then a couple of hours of work.
If I understand you, to merge local and live database, until now I'm using other software such as NavicatPremium, it has Data Sycn feature.
This can be achieved live using spring-xd, create a JDBC Stream to pull data from one db and insert into the other. (This acts as streaming so you don't have to disturb any environment)
The first thing you need to do is asses if it would be easier to do some copy-paste data entry instead of a migration script. Sometimes the best answer is to suck it up and do it manually using the CMS interface. This avoids any potential conflicts with merging primary keys, but you may need to watch for references like the creator of a post or similar data.
If it's just outright too much to manually migrate, you're stuck with writing a script or finding one that is already written for you. Assuming there's nothing out there, here's what you do...
ALWAYS MAKE A BACKUP BEFORE RUNNING MIGRATIONS!
1) Make a list of what you need to transfer. Do you need users, posts, etc.? Find the database tables and add them to the list.
2) Make a note all possible foreign keys in the database tables being merged into the new database. For example, wp_posts has post_author referencing wp_users. These will need specific attention during the migration. Use this documentation to help find them.
3) Once you know what tables you need and what they reference, you need to write the script. Start by figuring out what content is new for the other database. The safest way is to do this manually with some kind of side-by-side list. However, you can come up with your own rules on how to automatically match table rows. Maybe to check for $post1->post_content === $post2->post_content in cases the text needs to be the same. The only catch here is the primary/foreign keys are off limits for these rules.
4) How do you merge new content? The general idea is that all primary keys will need to be changed for any new content. You want to use everything except for the id of post and insert that into the new database. There will be an auto-increment to create the new id, so you wont need the previous id (unless you want it for script output/debug).
5) The tricky part is handling the foreign keys. This process is going to vary wildly depending on what you plan on migrating. What you need to know is which foreign key goes to which (possibly new) primary key. If you're only migrating posts, you may need to hard-code a user id to user id mapping for the post_author column, then use this to replace the values.
But what if I don't know the user ids for the mapping because some users also need to be migrated?
This is where is gets tricky. You will need to first define the merge rules to see if a user already exists. For new users, you need record the id of the newly inserted users. Then after all users are migrated, the post_author value will need to be replaced when it references a newly merged user.
6) Write and test the script! Test it on dummy databases first. And again, make backups before using it on your databases!
I've done something simillar with ETL (Extract, Transform, Load) process when I was moving data from one CMS to another.
Rather than writing a script I used a Pentaho Data Integration (Kettle) tool.
The Idea of ETL is pretty much straight forward:
Extract the data (for instance from one database)
Transform it to suit your needs
Load it to the final destination (your second database).
The tool is easy to use and it allows you to experiment with various steps and outputs to investigate the data. When you design a right ETL proces, you are ready to merge those databases of yours.
How can this be done without running a tonne of mysql commands?
No way. If both local and web sites are running at the same time how can you prevent not having the same ids' with different content?
so if you want to do this you can use mysql repication.i think it will help you to merge with different database mysql.

What is the procedure to normalize a database with PHP?

I just took over a pretty terrible database design job, which heavily use comma separated value to store data. I know I know, it is hell.
The db is mysql, currently accessing it using MySql Workbench.
I already had idea in mind what to remove, and what new relations table needed.
So, my question is, how shall I proceed by migrating comma separated data to the new table? Any tools specialize for normalizing database?
Edit:
The server code is in PHP.
Define you new tables and attributes first.
Then, use PHP or Python or your favorite language with MySQL calls and write a 1 time converter which loops and reads the old table(s) and records and inserts the proper records into the new tables.
It appears you are looking for standard practices. There are varying degree of denormalized databases out there. The ones I have come across have been normalized with custom code and tools.
SQL Server Integration Services (SSIS) can be used for some case. In your case, I'd build a script for the migration that involves:
creation of normalized tables
creating stored procedure or PHP script(s) to read data from denormalized table, transform it and load it into normalized table
creating a log table or log file
performing the migration in sandbox; write logs while doing so
version control the script
correct the proc/script as needed
create another sandbox
run the full script on sandbox
if successful, run the full script on prod (with logging)
SSIS is used for ETL in many organizations; it's standard tool for Microsoft BI stack and can also be used to migrate data between non-Microsoft DBs also.
Open Source ETL tool called Talend might also help in transforming your data. I personally believe that a PHP script will be the fastest and easiest to manipulate data.

Using Memcache, Should I use PDO or an ORM?

I am working on a project with a custom HTML5 front end and a backend I've designed from experience. The backend is composed of a message queue and a cache - currently I've chosen Beanstalk and Memcache because I'm famliar with them but I am open to suggestions.
My question though comes from how my coder is interfacing with the MySQL DB we are using to store the data. The idea is to pre-cache most or all of the DB so the site runs really fast. It's not a huge DB so RAM for Memcache shouldn't be an issue. However, my coder is using CodeIgniter with GreenBean. I've never heard of GreenBean before and when I google it I get almost nothing that isn't related to greenbeans the food. What little I could find suggested it was an ORM which fits from what my coder has told me.
The problem is this. With raw PDO my pre-caching scheme is simple - I would grab each row from each table and store it in the cache with a key. Then every time I needed that data I would look at the cache first for it and then the DB. If something is changed on the backend then I only need to update that row in the DB and the associated key in the cache.
With an ORM, if I store the entire ORM object serialized into the cache then it holds a bunch of related data. Data that could be incorrect if something were changed. For example, you have a DB of employees that is linked to the office they work in and the dept they work in. The ORM grabs the office and the dept and we store all of that in the cache. But if the office address changes the ORM object for every employee in that office is now stale/incorrect.
In that example, just letting the cache expire probably isn't an issue most of the time. But in my application, that data should really get updated immediately. So in a simple PDO scheme you flush the cache keys related to the data that changed and every future page call gets the updated data. But with an ORM you have lots and lots of cached object instances that might be incorrect and no good way of finding them. So it seems to me you are now left with some form of indexing of your cached objects and when you change something simple you could be flushing and refilling a big chunk of the cache. The site gets really slow then.
Typically I would just cache a DB result after the first time I needed it but in this case I think that could end up being really slow for a lot of users that make the first requests that particular set of data. Additionally, there are some search features that could require a lot of data from the DB. Thus my desire to pre-cache.
So in this case I'm thinking an ORM would hurt the site's performance. I'm thinking I'm not the first person to have this issue though. Is there an ORM out there that would handle this scenario well? Is there a better backend architecture I'm missing?
Thanks

PHP website without mysql

I am currently working on an existing website that lists products, there are currently a little over 500 products.
The website has a text file for every product and I want to make a search option, thinking of reading all the text files and create an xml document with the values once a day that can be searched.
The client indicated that they wanted to add products and is used to add them using the text files. There might be over 5000 products in the future so I think it's best to do this with mysql. This means importing the current products and create a crud page for products.
Does anyone have experience with a PHP website that does not use MySQL? Is it possible to keep adding text files and just index them once a day even if it would mean having over 5000 products?
5000 seems like an amount that's still managable to index with a daily cron job. As long as you don't plan on searching them real-time, it should work. It's not ideal, but it would work.
Yes, it is very much possible, NOT plausible that you use files for these type of transactions.
It is also better to use XML instead of normal TXTs for the job. 5000 products with what kind of data associated to them might create problems in future.
PS
Why not MySQL?
Mysql was made because file based databases are slow and inaccurate.
Just use mysql. If you want to keep your old txt based database, just build an easy script that will import each file one by one and create corresponding tables in your sql database.
Good luck.
It's possible, however if this is a anything more than simply an online catalog, then managing transaction integrity is horrendously difficult - and that you're even asking the question implies that you are not in a good position to implement the kind of controls required. And as you've already discovered, it doesn't make for easy searching (BTW: mysql's fulltext indexing is a very blunt instrument - it's not a huge amount of effort to implement an effective search engine yourself - or there are excellent ones available off-the-shelf, e.g. mnogosearch)
(as a conicdental point, why XML? It makes managing the data much more complicated than it needs to be)
and create a crud page for products
Why? If the client wants to maintain the data via file uploads and you already need to port the data, then just use the same interface - where the data is stored is not relevant just now.
If there are issues with hosting+mysql, then using SQLite gives most of the benefits (although it wion't scale as well).

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