I'm currently putting together (on old fashioned paper) a layout for my new database, but was told I should probably lay it out as a scheme, which is true.
Is there a tool that allows me to create my table structure/scheme in a plan type layout interface with all relationships and when it's finished it automagically creates the tables in the database and spits out the schema as a file I can print and share with others?
MySQL Workbench sounds like just the ticket.
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I am using Entity Framework to handle the database in a server application. The server application is deployed to multiple nodes sitting behind a load balancer. I have now discovered the need to rename some of the tables and some of the table columns in the database. The problem is that I will need to do this without any down-time.
If I was writing my own database layer I could simply check the structure of the database and then run different code depending on if the database structure was upgraded or not and then I could potentially have 0% downtime.
Is it possible to do something like this in entity framework 4 or how do I actually make database changes in production with entity framework? I have searched the web for any solution but to no success. I have also considered having 2 entity framework instances in my app but the amount of code I have to write to switch between them would be far too much and error prone.
So to summarize the question:
Is there any way to rename tables and columns in a database in a production environment using Entity Framework 4 and without any downtime whatsoever?
EDIT
A new idea I got would be to create a view in place of the old table with the old naming scheme referencing the new table. I dont know if this will work. For it to work Entity Framework needs to accept this view like it would be a normal table. Could this be a good idea? Anyone tried anything like this with EF4 ?
Okay! Here is what thought I got -
Create new table in DB than renaming and build EntityFramework solution on that.
You need to deploy this by taking one server off from loadbalancer, update it,point entity framework code to new table structure and then again attach to loadbalancer.
Make the same procedure for all the servers in loadbalancer one by one. Once all are up with updated patch then sync old table and new table and then just delete old table. I am suggesting synching these tables so that you have all the data without data loss might happen in above process.
I'm using the latest version of MySQL Workbench 5.2.40.
In the EER Diagram, is there a way to copy/paste columns between tables, as well as move columns from one table to another using drag and drop?
I don't see any any such feature now. If this is the case, it would be difficult to do preliminary design using Workbench considering that it will be tedious to modify or correct your designs later on. I might as well go straight to the physical design using PhpMyAdmin since I can copy-paste portions of SQL statements when altering tables.
Any work-around modifying columns in Workbench? Thanks
The current version of MySQL Workbench is 6.0.7 and yes, you can copy and paste column definitions using the context menu in the table editor (not directly in the diagram). Just open the tables you want to edit. Usually, the editor is reused if an object of the same type is opened for editing, but there's an entry in the context menu of the objects that allows to open the object in a new tab. This way you can have two table editors on 2 tabs and can easily switch back and forth for copying e.g. column definitions.
I handle these cases this way :
do the modifications on the physical tables (using pma, or the "schema editor" tab of mwb, or the command-line)
then synchronize database and model
In fact, I'd find useful to be able to manipulate the schema directly in SQL; GUI would then (as pma is) simply be a more convenient way to to some actions ('Create a table' would generate, then execute, an SQL 'CREATE TABLE' statement)
But it would probably mean a redesign from scratch - at least for the way the schema is stored.
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.
I have two servers that share an original ancestor codebase, but which have changed during the past couple of months in terms of database schema (I'm using mysql). I'm about to use the second one as my new production server, but I have to update the data (there are new users, there's new data related to those users, etc.). I want the data in the server that's now live, but has the old schema to have the authority, yet I want the schema in the new one to be the final one. So it's kind of a weird merge: I want data from the old server to be imported into a new server with a (not vastly) different schema.
I was thinking of simply making a dump of the server with the most up-to-date data, but then loading it wouldn't work since the schema has changed quite a bit.
I was also thinking on dumping the schema of the new server, applying it to a copy of the old one, then dumping the data from the latter and loading it into the new one, but I'm not sure how to go about doing that and if it's the safest option.
I develop on mac OS X and both of my servers are debian.
Applying the schema from the new server to the old and then migrating data is the safest option, largely because it forces you to evaluate what specifically has changed and what you want to do about that in terms of data (e.g., where a new column is added, what do you want to put in it)?
Since you mentioned the schemata are not massively different, simply doing a mysqldump without data (i.e., tables only) of each server and manually comparing (e.g., with diff) would tell you what columns are different. You can then apply those changes with ALTER on the old database.
It's all a little kludgy, but then ultimately there isn't really a non-kludgy way of doing this.
Look here: http://bitbucket.org/idler/mmp - it is a tool for mysql schema versioning, but only schema, not the data. First you must migrate your schema, then load your new data.
There are a lot of database migration tools available for Ruby, .NET, SQL Server, etc.
Is there anything good for Access/VBA? I've had to roll my own a few times, but I'd really like to offload that burden onto a well-written tool.
The ideal solution would be something like FluentMigrator or RikMigrations with classes or modules that contain DAO code.
When there are only new columns to add personally I tend to do this in the user interface. I have a temporary table in the backend database which is never locked by any users and when creating a new column I add it 1st to this table and double check all the properties are correct. Then when the users are not using the backend database I copy and paste it, then allow users back in.
This means the backend database is unavailable for the shortest period of time and I am not rushed when creating the columns.