How to log mysql database structural changes - mysql

I'm working with a project which is using mysql as the database. The application is hosted with many clients and we are doing upgrades for the current live systems often.
There are some instances where the client has change the database structure(adding new tables) and causes some unexpected db crashes.
I need to log all the structural changes which were done at that database, so we can find the correct root cause for that. We can't do it 100% correct with diff tool because it will not show the intermediate changes.
I found http://www.liquibase.org/ tool but seems little bit complex.
Is there any well known technique or a tool to track database structural changes only.

well from mysql studio you can generate all object's schema definition and compare them with your standard schema definition and this way you can compare two database schema...
generate scrips of both database (One is client's Database and One is master copy database) and then compare it using file compare tool would be the best practice according to me because this way you can track which collumn was added, which column was deleted, which index was added like wise without any tool download.
Possiable duplication of Compare two MySQL databases ?
Hope this helps.

If you have an application for your clients to manage these schema changes, you can use a mechanism at application level. If you have a Python and Django-based solution, you could probably use South which provides schema change tracking and rollbacks.

Related

merge design of mysql between localhost and server?

I'm kinda new to this kind of problem. I'm developing a web-app and changing DB design trying to improve it and add new tables.
well since we had not published the app since some days ago,
what I would do was to dump all the tables in server and import my local version but now we've passed the version 1 and users are starting to use it.
so I can't dump the server, but I still would need to update design of server DB when I want to publish a new version. What are the best practices here?
I like to know how I can manage differences between local and server in mysql?
I need to preserve data in server and just change the design, data on local DB are only for test.
Before this all my other apps were small and I would change a single table or column but I can't keep track of all changes now, since I might revert many of them later and managing all team members on this is impossible.
Assuming you are not using a framework that provides a migration tool for database, you need to keep track of the changes manually.
Create a folder sql_upgrades (or whatever name you name) in your code repository
Whenever a team member updates the SQL schema, he creates a file in this folder with the corresponding ALTER statements, and possibly UPDATE, CREATE TABLE etc. So basically the file contains all the statements used to update the dev database.
Name the files so that it's easy to manage, and that statements for the same feature are grouped together. I suggest something like YYYYMMDD-description.sql, e.g. 20150825-queries-for-feature-foobar.sql
When you push to production, execute the files to upgrade you SQL schema in production. Only execute the files that have been created since your last deployment, and execute them in the order they have been created.
Should you need to rollback a file, check the queries it contains, and write queries to undo what was done (drop added columns, re-create dropped columns, etc.). Note that this is "non-trivial", as many changes cannot be rolled back fully (e.g. you can recreate a dropped column, but you will have lost the data inside).
Many web frameworks (such as Ruby of Rails) have tools that will do exactly that process for you. They usually work together with the ORM provided by the framework. Keeping track of the changes manually in SQL works just as well.

Compare database differences and get SQL output

I need ability to compare two similar databases. One will be slightly newer than the other and have changes to the structure of the database as well as possibly the content within it.
So far I have tried using liquibase but it doesn't seem to be comparing properly.
I have also tried the MySQL Diff Perl module which works but doesn't consider content.
Main Question:
Does anyone know any solutions that will give back SQL for both structural and content differences and generate a SQL script?
A bit more info:
The intended use for this is when making updates and installing MODs to phpBB so that the forum can be included in the build process along with the rest of our website. Which has a 4 tier process (local, development, staging, production).
When installing the phpBB updates and MODs I will make a dump of the current production database and lock the site so no new data can be added whilst I make changes. That way databases shouldn't come out of sync.
When installing MODs and updates sometimes the database structure changes and also the data within tables, especially when adding things requiring extra permissions etc.
The solution I use therefore will be used to compare the local database with the upgraded changes to the production database, providing me with a script I can run on each tier in the build process, rather than manually installing the update/MOD on each.
You can use SQLyog Database synchronization tool to sync two databases,either one-way or two-way. By far this is the best data comparison tool for MySQL GUI. And, Schema sync for schema comparisons between two databases.
Both tools can generate SQL scripts.
I've actually found a way to do it via Navicat for MySQL using the Tools > Structure Syncronization option.
This will give SQL statements for differences in structure between the two databases.
Then do do the data differences you can use Data Syncornization.
I've managed to copy out the SQL script for differences in structure. However the data syncronization seems to be more of an internal Navicat thing. I'm sure there's a way that the queries could be extracted though.
Please note I'm using a license version so not sure if its available in the free to use one.

Are there generic options for version control within a database?

I have a small amount of experience using SVN on my development projects, and I have just as little experience with relational databases. I know the basic concepts like tables, and SQL statements, but I'm far from being an expert.
What I'd like to know is if there are any generic version control type systems like SVN, but that work with a database rather than files. I would like the same kind of features you get with SVN like the ability to create branches, create tags, and merge branches together. Rather than a revision number being associated to a version of a file repository it would be associated with a version of the database.
Are their any generic solutions available that can add this kind of functionality independent of the actual database schema? I'd be interested in solutions that work with MySQL or MS SQL Server.
I should also clarify that I'm trying to version control the data not the schema. I would expect the schema to remain constant. So really it seems like I want a way to create a log of all the INSERT, UPDATE, and DELETE requests sent the the database between each version of the data. That way any version could be recreated by resending all the SQL statements that have been saved up to the desired version.
You can script all your DDL, stored procedures and such to regular text files.
Then you can simply use SVN for database versioning.
I've never found a solution that works as well as Subversion, but here's a few things I've done that have helped:
Make scripts that will create the schema and populate any initial data. Then make an update script for each change after that. It's a fairly manual process, but it works. There's extra things that help like storing the current version number in a table in the db and making sure that the scripts are idempotent.
Store the full development db in Subversion. This doesn't usually work out too well for me if there is a lot of data or it is frequently changed. But in some projects is could work.
I keep and maintain create scripts in my version control system.
There are two things I can think of:
http://www.liquibase.org/ - provides a way of generally managing database changes. Creates files that get committed into source control, and it helps manage changes across different development databases, etc.
http://www.viget.com/extend/backup-your-database-in-git/ - this describes a strategy for backing up a database into source control, but the same strategy can be used just on the schema. In this scheme, the database would be in a separate area from your main code. (This can be used with other source control systems too.)

How to collaborate on mysql schema?

I'm working with another dev and together we're building out a MySQL database. We've each got our own local instances of MySQL 5.1 on our dev machines. We've not yet been able to identify a way for us to be able to make a local schema change (eg: add a field and some values for that field) and then export some kind of script or diff file that the other can import in. I've looked into Toad and Navicat's synchronization features but they seem oriented towards synchronizing between two instances, not an instance and an intermediate file. We thought MySQL Workbench would be great but this but the synchronization feature just seems plain broken. Any other ideas? How do you collaborate with others on the schema?
First of all put your final SQL schema into version control. So you'll always have a version of it with all changes. It can be a plain SQL file. Every developer in the team can use it as starting point to created his copy database. All changes must be applied to it. This will help you to find conflicts faster.
Also I used such file to create a test database to run unit-tests after each submit. So we were always sure that production code is working.
Then you can use any migration tool to move changed between developers. Here is similar question about this:
Mechanisms for tracking DB schema changes
If you're using PHP then look at Doctrine migrations.

How to synchronize development and production database

Do you know any applications to synchronize two databases - during development sometimes it's required to add one or two table rows or new table or column.
Usually I write every sql statement in some file and during uploading path I evecute those lines on my production database (earlier backing it up).
I work with mySQL and postreSQL databases.
What is your practise and what applications helps you in that.
You asked for a tool or application answer, but what you really need is a a process answer. The underlying theme here is that you should be versioning your database DDL (and DML, when needed) and providing change scripts to be able to update any version of your database to a higher version.
This set of links provided by Jeff Atwood and written by K. Scott Allen explain in detail what this ought to look like - and they do it better than I can possibly write up here: http://www.codinghorror.com/blog/2008/02/get-your-database-under-version-control.html
For PostgreSQL you could use Another PostgreSQL Diff Tool . It can diff two SQL Dumps very fast (a few seconds on a db with about 300 tables, 50 views and 500 stored procedures). So you can find your changes easily and get a sql diff which you can execute.
From the APGDiff Page:
Another PostgreSQL Diff Tool is simple PostgreSQL diff tool that is useful for schema upgrades. The tool compares two schema dump files and creates output file that is (after some hand-made modifications) suitable for upgrade of old schema.
Have scripts (under source control of course) that you only ever add to the bottom off. That combined with regular restores from your production database to dev you should be golden. If you are strict about it, this works very well.
Otherwise I know lots of people use redgate stuff for SQLServer.
Another vote for RedGate SQL Compare
http://www.red-gate.com/products/SQL_Compare/index.htm
Wouldn't want to live without it!
Edit: Sorry, it seems this is only for SQL Server. Still - if any SQL Server users have the same question I'd definitely recommend this tool.
If you write your SQL statements for your development database (which are, I imagine, series of DDL instructions such as CREATE, ALTER and DROP), why don't you keep track of them by recording them in a table, with a "version" index? You will then be able to:
track your version changes
make a small routine allowing the "automatic" update of your production database by sending the recorded instructions to the database.
I really like the EMS tools.
There tools are available for all popular DB's and you have the same user experience for every type of DB.
One of the tools is the DB Comparer.
TOAD
saved many an ass several times in the past. Why do people run sql with no exit strategy?
the redgate one is good also.
Siebel (CRM, Sales, etc. management product) has a built-in tool to align the production database with the development one (dev2prod).
Otherwise, you've got to stick with manually executed scripts.
Navicat has a structure synchronisation wizard that handles this.
I solve this by using Hibernate. It can detect and autocreate missing tables, columns, etc.
You could add some automation to your current way of doing things by using dbDeploy or a similar script. This will allow you to keep track of your schema changes and to upgrade/rollback your schema as you see fit.
Here's a straight linux bash script I wrote for syncing Magento databases... but you can easily modify it for other uses :)
http://markshust.com/2011/09/08/syncing-magento-instance-production-development
DBV - "Database version control, made easy!" (PHP)