I am curious if there is a standard or open-source application that allows a small team of developers to share MySQL database update/modification scripts?
Right now all the developers have a VM with their own instance of a database, so there are no conflicts and each can have separate development environment. When one makes a DB change we add the SQL scripts to a SQL text file in SVN, which is then run by each dev in their own environment when necessary.
The issue that we are having is that when someone updates the file, the others run the script, and then we add additional changes. It gets very confusing and we get errors if there are ALTER table statements, etc.
We don't want to use DB replication because if one dev destroys their DB we don't want the others to be affected.
We use ExpressionEngine and I've noticed they use PHP to check/validate SQL updates, is that the direction we will need to go?
Anyone else deal with this issue? If so, what did you end up using?
A fairly simple solution is to have a directory, instead of a single file. Then each time a Dev makes a change, they add a "patch file" to the directory. Other developers can get their databases up to date by running any patches they haven't yet run.
This can even be automated by having a metadata table in the database to track which patches have been run and writing a script to run any that haven't.
Lorna Mitchell has blogged about some strategies to doing this:
http://www.lornajane.net/posts/2010/simple-database-patching-strategy
http://www.lornajane.net/posts/2012/taking-on-a-database-change-process
The comments are full or people recommending various tools to help with the process. Personally, I just have a fairly simple script and have no need for larger libraries, but your mileage may vary.
Perhaps what you want is migration support.
Then, you put the migration code in whatever CVS you use and each team member migrates (i.e. runs the migration script) on their box, and this syncs all databases.
The framework I use (yii) supports it but I'm pretty sure there are some standalone solutions if you don't want to have to bring the whole framework over.
I'm developing a website. I have a remote and local copy, and I develop on the local copy, and then when I've got a stable version I copy up all the PHP files and then I have to make the remote live MySQL database look like my local one.
I typically delete the remote, live database (as long as I'm not deleting new changes) and re-import it from a .sql file using PHPMyAdmin.
I want to set up a more reliable, correct, and idiot-proof, version updating system for my database. Is MySQL server replication the right answer? How is this usually done?
No, you never want a development/test environment replicating to a live database. If you accidentally dropped a table, you'd wipe out the live site.
Better to use something like http://www.mysqldiff.org/
Arguably the best way to do this is migrations. Migrations are essentially code which is stored with your application that update the database schema as it changes. The nice thing about migrations is that they can be versioned and it's easy to associate changes in the database schema with changes in the code. When used correctly, you can also use migrations to roll back the database to any previous state.
For an example, check out the use of migrations in the Yii framework.
So, I have a development and production environment that are accessing the same BitBucket repository, and changes I push to the repo, I pull down on the production server by using hg pull and hg update.
This keeps my PHP code all up to date and works fine.
But I could use some advice keeping my MySQL schemas in sync between the two environments. For example I quite often make changes on the development machine that I need to reflect on the production server.
Any advice on how to do this would be very gratefully received.
What you are trying to do, in a nutshell, is version your database schema so that it stays in line with the code as things change. The critical parts of being able to do that is to be able to track the changes to the DB schema, and also being able to track the current state of the DB schema (ie. what version it is at)
One way to track the changes to the schema would be to manually script all changes to the schema. These change scripts are essentially your "diffs" between versions of the schema. Another way to generate these change files would be to use a program that can generate a diff between two databases, or between a database and a create script. In theory, you should be able to develop a pre-commit hook script that can generate the alter script from the current database for that working copy and the previous database for that working copy, but this isn't a trivial task.
Once you have your DB being versioned, you now have to solve the problem of applying those changes on Update. To do this, you will need to develop a post-update hook that can look at the database (probably at some sort of Version table within it that links to the Mercurial changeset Id) and determine what scripts need to be run in order to get the DB up to date.
Since Mercurial allows you to update to a previous version, you will either have to only have non-breaking changes to your database, or simply not allow (in the social sense or the technical sense) the production working copy to be updated to previous versions. Regardless of how you handle it, the post-update hook script that is doing the actual DB updates probably needs to be smart enough to try to apply DB alter scripts that it has already applied.
There are obviously a number of issues to resolve and lots of testing to do to get this all to work, and it isn't a pre-built solution for you by any means, but it should get you well on your way to automating your DB updates to keep them in line with your code. Good luck!
Take a look at the Rails framework. They use database migrations to manipulate (even create) the database. It integrates great with testing and across development machines too (for teams). It's Ruby (which many find preferable to PHP) so it won't work for you unless you switch, but it might give you some ideas on how to implement this for your application.
http://guides.rubyonrails.org/migrations.html
Migrations are a convenient way for
you to alter your database in a
structured and organized manner. You
could edit fragments of SQL by hand
but you would then be responsible for
telling other developers that they
need to go and run them. You’d also
have to keep track of which changes
need to be run against the production
machines next time you deploy.
Active Record tracks which migrations
have already been run so all you have
to do is update your source and run
rake db:migrate. Active Record will
work out which migrations should be
run. It will also update your
db/schema.rb file to match the
structure of your database.
I would like to setup two environments for my new website written in PHP. One - to develop new versions and test them. And second production where my actual stable version of website will be available.
Website in PHP will consist of many PHP and other files (JS, images, and so on). So I think how to prepare this environment in best way to make it easy to do source control, fast copy website from development environment to production environment and to make development version available for people on the web so they will be able to see actual work progress and suggest changes or report bugs.
Could you please give me some advice where to go from this starting point? Are there books about this (from practical point of view?) or do you have experience or tips what to watch out and what is important to make this process easy and good for me and other people involved in developing new project?
For starters use the following three:
SVN - this will give you source control and allow you to track changes. You may want to get GUIs on top of this (Tortoise is a popular one) to ease the learning curve.
RSYNC - this will allow you to streamline your syncing between local and remote site with a single command. RSYNC uses a diff engine to sync which means that incremental syncs happen in a matter of seconds. During intense programming, I will sometimes sync 4-5 times in one hour pushing out little changes real fast just because I can so easily.
MySQLDump - This will allow you to import/export data from your production site. I usually do this once a week to get production data on my local servers which not only gives me a local backup but also lets me toy around with production data on a local test environment.
Those three alone will save you a lot of time in the long run and allow you to scale. Later on you can look into an automated build tools, unit testing frameworks, xml documentation framework and the like to build some serious products.
I work with a setup like this, so I can give you some tips on how to do this. I've been doing this for a while now, working out the kinks here and there, and feel like this is a setup I can honestly say is pretty darn productive.
Small note: I work on OSX, so the specific applications used might be a bit different from you if you're a linux/windows user.
I run a production 'server' on my Mac, using MAMP (www.mamp.info) to easily supply me with an Apache server with PHP and MySQL. You could use a similar tool such as XAMPP or install everything manually, it's really up to you.
Then I have my live servers, where my websites and customer websites are hosted. For each new website project (let's take abc.com as an example) I create a subdomain called staging.abc.com, on which I do my testing. It's always a good thing to test things on the exact same hard- and software before actually going live.
I use Subversion (or in short, SVN) for my versioning needs, with the added bonus that I can easily add 'hooks' to automatically update my online production server whenever I send my newly updated version to the SVN server. SVN also allows you to easily work with more than one person on the same project. For more information on SVN and how to use it, I suggest the great (and free) online book found here: http://svnbook.red-bean.com/
So in short: I work locally with MAMP providing me with a local 'working' server. After that, I test online on a staging.abc.com location to see if everything works well, and to possibly allow others to see the project (in case you want your client to see what's going on, for example), and after that I actually publish the project by putting it on the actual domain.
There are many more things that can be done to optimize your workflow, but this should get you started.
Hope this helps!
-Dave
I prefer to have development occur on the developers local box if possible. If other developers are involved, you probably want to setup your version control such that both the database schema, javascript, css, and the php code can be checked out and setup on a developer's personal box pretty easily (assuming they have the correct LAMP/WAMP setup)
I've also seen it where people maintain a test website on a server where active development occurs. I would avoid this for active development, but use this for black-box testing of the latest checked in code (the latest build).
Once your test website checks out, then its a matter of exporting the code from your version control to the location the live website is. With svn, you can really just do an update of the live code with svn update specifying a revision or tag that indicates the current live version.
I would further recommend keeping some settings, like db access/username/pass, in a separate included file that is not version controlled. Keep this elsewhere, let developers plug in the access rights to their local database on their PC. On your server, plug in everything you need to access the database there. This should be really trivial code (defining a few variables) so not having it version controlled shouldn't be a big deal. If you like, you could version control a templated version, but I wouldn't put the real database info into version control.
Here is a pretty good starting place if you want to use MAMP or WAMP to develop locally and then push that to github and then update your live site from github:
http://www.mybringback.com/bringers/14509/git-local-and-shared-server-development-environment-with-ssh-setup/
Hope that helps.
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What are the best methods for tracking and/or automating DB schema changes? Our team uses Subversion for version control and we've been able to automate some of our tasks this way (pushing builds up to a staging server, deploying tested code to a production server) but we're still doing database updates manually. I would like to find or create a solution that allows us to work efficiently across servers with different environments while continuing to use Subversion as a backend through which code and DB updates are pushed around to various servers.
Many popular software packages include auto-update scripts which detect DB version and apply the necessary changes. Is this the best way to do this even on a larger scale (across multiple projects and sometimes multiple environments and languages)? If so, is there any existing code out there that simplifies the process or is it best just to roll our own solution? Has anyone implemented something similar before and integrated it into Subversion post-commit hooks, or is this a bad idea?
While a solution that supports multiple platforms would be preferable, we definitely need to support the Linux/Apache/MySQL/PHP stack as the majority of our work is on that platform.
In the Rails world, there's the concept of migrations, scripts in which changes to the database are made in Ruby rather than a database-specific flavour of SQL. Your Ruby migration code ends up being converted into the DDL specific to your current database; this makes switching database platforms very easy.
For every change you make to the database, you write a new migration. Migrations typically have two methods: an "up" method in which the changes are applied and a "down" method in which the changes are undone. A single command brings the database up to date, and can also be used to bring the database to a specific version of the schema. In Rails, migrations are kept in their own directory in the project directory and get checked into version control just like any other project code.
This Oracle guide to Rails migrations covers migrations quite well.
Developers using other languages have looked at migrations and have implemented their own language-specific versions. I know of Ruckusing, a PHP migrations system that is modelled after Rails' migrations; it might be what you're looking for.
We use something similar to bcwoord to keep our database schemata synchronized across 5 different installations (production, staging and a few development installations), and backed up in version control, and it works pretty well. I'll elaborate a bit:
To synchronize the database structure, we have a single script, update.php, and a number of files numbered 1.sql, 2.sql, 3.sql, etc. The script uses one extra table to store the current version number of the database. The N.sql files are crafted by hand, to go from version (N-1) to version N of the database.
They can be used to add tables, add columns, migrate data from an old to a new column format then drop the column, insert "master" data rows such as user types, etc. Basically, it can do anything, and with proper data migration scripts you'll never lose data.
The update script works like this:
Connect to the database.
Make a backup of the current database (because stuff will go wrong) [mysqldump].
Create bookkeeping table (called _meta) if it doesn't exist.
Read current VERSION from _meta table. Assume 0 if not found.
For all .sql files numbered higher than VERSION, execute them in order
If one of the files produced an error: roll back to the backup
Otherwise, update the version in the bookkeeping table to the highest .sql file executed.
Everything goes into source control, and every installation has a script to update to the latest version with a single script execution (calling update.php with the proper database password etc.). We SVN update staging and production environments via a script that automatically calls the database update script, so a code update comes with the necessary database updates.
We can also use the same script to recreate the entire database from scratch; we just drop and recreate the database, then run the script which will completely repopulate the database. We can also use the script to populate an empty database for automated testing.
It took only a few hours to set up this system, it's conceptually simple and everyone gets the version numbering scheme, and it has been invaluable in having the ability to move forward and evolving the database design, without having to communicate or manually execute the modifications on all databases.
Beware when pasting queries from phpMyAdmin though! Those generated queries usually include the database name, which you definitely don't want since it will break your scripts! Something like CREATE TABLE mydb.newtable(...) will fail if the database on the system is not called mydb. We created a pre-comment SVN hook that will disallow .sql files containing the mydb string, which is a sure sign that someone copy/pasted from phpMyAdmin without proper checking.
My team scripts out all database changes, and commits those scripts to SVN, along with each release of the application. This allows for incremental changes of the database, without losing any data.
To go from one release to the next, you just need to run the set of change scripts, and your database is up-to-date, and you've still got all your data. It may not be the easiest method, but it definitely is effective.
The issue here is really making it easy for developers to script their own local changes into source control to share with the team. I've faced this problem for many years, and was inspired by the functionality of Visual Studio for Database professionals. If you want an open-source tool with the same features, try this: http://dbsourcetools.codeplex.com/
Have fun,
- Nathan.
If you are still looking for solutions : we are proposing a tool called neXtep designer. It is a database development environment with which you can put your whole database under version control. You work on a version controlled repository where every change can be tracked.
When you need to release an update, you can commit your components and the product will automatically generate the SQL upgrade script from the previous version. Of course, you can generate this SQL from any 2 versions.
Then you have many options : you can take those scripts and put them in your SVN with your app code so that it'll be deployed by your existing mechanism. Another option is to use the delivery mechanism of neXtep : scripts are exported in something called a "delivery package" (SQL scripts + XML descriptor), and an installer can understand this package and deploy it to a target server while ensuring structural consistency, dependency check, registering installed version, etc.
The product is GPL and is based on Eclipse so it runs on Linux, Mac and windows. It also support Oracle, MySQL and PostgreSQL at the moment (DB2 support is on the way). Have a look at the wiki where you will find more detailed information :
http://www.nextep-softwares.com/wiki
Scott Ambler produces a great series of articles (and co-authored a book) on database refactoring, with the idea that you should essentially apply TDD principles and practices to maintaining your schema. You set up a series of structure and seed data unit tests for the database. Then, before you change anything, you modify/write tests to reflect that change.
We have been doing this for a while now and it seems to work. We wrote code to generate basic column name and datatype checks in a unit testing suite. We can rerun those tests anytime to verify that the database in the SVN checkout matches the live db the application is actually running.
As it turns out, developers also sometimes tweak their sandbox database and neglect to update the schema file in SVN. The code then depends on a db change that hasn't been checked in. That sort of bug can be maddeningly hard to pin down, but the test suite will pick it up right away. This is particularly nice if you have it built into a larger Continuous Integration plan.
Dump your schema into a file and add it to source control. Then a simple diff will show you what changed.
K. Scott Allen has a decent article or two on schema versioning, which uses the incremental update scripts/migrations concept referenced in other answers here; see http://odetocode.com/Blogs/scott/archive/2008/01/31/11710.aspx.
If you are using C#, have a look at Subsonic, a very useful ORM tool, but is also generates sql script to recreated your scheme and\or data. These scripts can then be put into source control.
http://subsonicproject.com/
I've used the following database project structure in Visual Studio for several projects and it's worked pretty well:
Database
Change Scripts
0.PreDeploy.sql
1.SchemaChanges.sql
2.DataChanges.sql
3.Permissions.sql
Create Scripts
Sprocs
Functions
Views
Our build system then updates the database from one version to the next by executing the scripts in the following order:
1.PreDeploy.sql
2.SchemaChanges.sql
Contents of Create Scripts folder
2.DataChanges.sql
3.Permissions.sql
Each developer checks in their changes for a particular bug/feature by appending their code onto the end of each file. Once a major version is complete and branched in source control, the contents of the .sql files in the Change Scripts folder are deleted.
We use a very simple but yet effective solution.
For new installs, we have a metadata.sql file in the repository which holds all the DB schema, then in the build process we use this file to generate the database.
For updates, we add the updates in the software hardcoded. We keep it hardcoded because we don't like solving problems before it really IS a problem, and this kind of thing didn't prove to be a problem so far.
So in our software we have something like this:
RegisterUpgrade(1, 'ALTER TABLE XX ADD XY CHAR(1) NOT NULL;');
This code will check if the database is in version 1 (which is stored in a table created automatically), if it is outdated, then the command is executed.
To update the metadata.sql in the repository, we run this upgrades locally and then extract the full database metadata.
The only thing that happens every so often, is to forget commiting the metadata.sql, but this isn't a major problem because its easy to test on the build process and also the only thing that could happen is to make a new install with an outdated database and upgraded it on the first use.
Also we don't support downgrades, but it is by design, if something breaks on an update, we restored the previous version and fix the update before trying again.
It's kind of low tech, and there might be a better solution out there, but you could just store your schema in an SQL script which can be run to create the database. I think you can execute a command to generate this script, but I don't know the command unfortunately.
Then, commit the script into source control along with the code that works on it. When you need to change the schema along with the code, the script can be checked in along with the code that requires the changed schema. Then, diffs on the script will indicate diffs on schema changes.
With this script, you could integrate it with DBUnit or some kind of build script, so it seems it could fit in with your already automated processes.
I create folders named after the build versions and put upgrade and downgrade scripts in there. For example, you could have the following folders: 1.0.0, 1.0.1 and 1.0.2. Each one contains the script that allows you to upgrade or downgrade your database between versions.
Should a client or customer call you with a problem with version 1.0.1 and you are using 1.0.2, bringing the database back to his version will not be a problem.
In your database, create a table called "schema" where you put in the current version of the database. Then writing a program that can upgrade or downgrade your database for you is easy.
Just like Joey said, if you are in a Rails world, use Migrations. :)
For my current PHP project we use the idea of rails migrations and we have a migrations directory in which we keep files title "migration_XX.sql" where XX is the number of the migration. Currently these files are created by hand as updates are made, but their creation could be easily modified.
Then we have a script called "Migration_watcher" which, as we are in pre-alpha, currently runs on every page load and checks whether there is a new migration_XX.sql file where XX is larger than the current migration version. If so it runs all migration_XX.sql files up to the largest number against the database and voila! schema changes are automated.
If you require the ability to revert the system would require a lot of tweaking, but it's simple and has been working very well for our fairly small team thus far.
Toad for MySQL has a function called schema compare that allows you to synchronise 2 databases. It is the best tool I have used so far.
I like the way how Yii handles database migrations. A migration is basically a PHP script implementing CDbMigration. CDbMigration defines an up method that contains the migration logic. It is also possible to implement a down method to support reversal of the migration. Alternatively, safeUp or safeDown can be used to make sure that the migration is done in the context of a transaction.
Yii's command-line tool yiic contains support to create and execute migrations. Migrations can be applied or reversed, either one by one or in a batch. Creating a migration results in code for a PHP class implementing CDbMigration, uniquely named based on a timestamp and a migration name specified by the user. All migrations that have been previously applied to the database are stored in a migration table.
For more information see the Database Migration article from the manual.
Try db-deploy - mainly a Java tool but works with php as well.
http://dbdeploy.com/
http://davedevelopment.co.uk/2008/04/14/how-to-simple-database-migrations-with-phing-and-dbdeploy.html
I would recommend using Ant (cross platform) for the "scripting" side (since it can practically talk to any db out there via jdbc) and Subversion for the source repository.
Ant will allow you to "back up" your db to local files, before making changes.
backup existing db schema to file via Ant
version control to Subversion repository via Ant
send new sql statements to db via Ant
IMHO migrations do have a huge problem:
Upgrading from one version to another works fine, but doing a fresh install of a given version might take forever if you have hundreds of tables and a long history of changes (like we do).
Running the whole history of deltas since the baseline up to the current version (for hundreds of customers databases) might take a very long time.
There is a command-line mysql-diff tool that compares database schemas, where schema can be a live database or SQL script on disk. It is good for the most schema migration tasks.