I have a table in MySQL that I need to join with a couple of tables in a different server. The catch is that these other tables are in Informix.
I could make it work by selecting the content of a MySQL table and creating a temp table in Informix with the selected data, but I think in this case it would be too costly.
Is there an optimal way to join MySQL tables with Informix tables?
I faced a similar problem a number of years ago while developing a Rails app that needed to draw data from both an Informix and a MySQL database. What I ended up doing was using of an ORM library that could connect to both databases, thereby abstracting away the fact that the data was coming from two different databases. Not sure if this will end up as a better technique than your proposed temp table solution. A quick google search also brought up this, which might be promising.
This can sometimes be solved in the database management system with a technique called federation. The idea is that you create virtual tables in one of the two systems that makes queries to the other database system on demand.
For both MySQL and MariaDB there is the FederatedX storage engine that unfortunately only works with other MySQL/MariaDB systems. This is a fork of the older, but as far as I know unmaintained, Federated storage engine.
Some might also consider migrating to MariaDB where you can use the CONNECT storage engine which contains an ODBC client.
What I ended up doing is manually (that is, from the php app) keeping in sync the mysql tables with their equivalents in informix, so I didn't need to change older code. This a temporary solution, given that the older system, which is using informix, is going to be replaced.
Related
I want to query data from 2 different database server using mysql. Is there a way to do that without having to create Federated database as Google Cloud Platform does not support Federated Engine.
Thanks!
In addition to #MontyPython's excellent response, there is a third, albeit a bit cumbersome, way to do this if by any chance you cannot use Federated Engine and you also cannot manage your databases replication.
Use an ETL tool to do the work
Back in the day, I faced a very similar problem: I had to join data from two separate database servers, neither of which I had any administrative access to. I ended up setting up Pentaho's ETL suite of tools to Extract data from both databases, Transform if (basically having Pentaho do a lot of work with both datasets) and Loading it on my very own local database engine where I ended up with exactly the merged and processed data I needed.
Be advised, this IS a lot of work (you have to "teach" your ETL tool what you need and depending on what tool you use, it may involve quite some coding) but once you're done, you can schedule the work to happen automatically at regular intervals so you always have your local processed/merged data readily accesible.
FWIW, I used Pentaho's community edition so free as in beer
You can achieve this in two ways, one you have already mentioned:
1. Use Federated Engine
You can see how it is done here - Join tables from two different server. This is a MySQL specific answer.
2. Set up Multi-source Replication on another server and query that server
You can easily set up Multi-source Replication using Replication channels
Check out their official documentation here - https://dev.mysql.com/doc/refman/8.0/en/replication-multi-source-tutorials.html
If you have an older version of MySQL where Replication channels are not available, you may use one of the many third-party replicators like Tungsten Replicator.
P.S. - There is no such thing in MySQL as a FDW in PostgreSQL. Joins across servers are easily possible in other database management systems but not in MySQL.
Two machines, each running mysql, each synchronized to the other peer-to-peer. I do not want a master db replicated. Rather, I want two users to be able to work on the data offline (each running a mysql server on his machine) and then when reconnected synchronize to each other. Any way to do this with mysql? Any other database I should be looking at to accomplish this better than mysql?
Two-way replication is provided by various database systems (e.g. SQLServer, Sybase etc.) but there are always problems with such a set up.
For example, if the same row is updated at the same time on the two databases, which update wins?
If your aim is to provide a highly-available MySQL database, then there are better options than using replication. MySQL has a clustering solution (though I've not had much success with it) or you can use things like DRBD and heartbeat to provide automatic failover with no loss of data.
If you mean synchronous writing back and forth, this would cause serious data consistency issues. I think you may be referring to MySQL replication, wherein a master server sends its updates to one or more slave database servers, which can be queried.
As for "Other Database Options" SQLServer supports a fairly advanced "replication" process for synchronizing the data between two or more db's. Looks like MySql has something like this as well though.
Is it possible create/configure MySQL for functionality like SQL Server's Linked Server?
If yes, would you please tell me how? I'm using MySQL 5.5.
MySQL's FEDERATED engine provides functionality similar to SQL Server's Linked Server (and Oracle's dblink) functionality, but doesn't support connecting to vendors other than MySQL. It's not clear from the question if you need the functionality to connect to vendors other than MySQL.
You might want to look into MySQL Proxy. This doesn't match the architecture of Linked Servers/dblink, but you can probably solve a similar set of problems that you would use Linked Servers/dblink to solve.
I am the developer of the MySQL Data Controller. Unfortunately, since we had lack of requests we have stopped development on it. The plugin was 100% functional with MySQL connecting to Oracle, MSSQL or MySQL.
Base on some requests, we had added back a blog and video about it :
http://www.acentera.com/mysql-datacontroller/
Regards,
Francis L.
Unfortunately you cannot link an entire MySQL database to another MySQL database like you can with MS SQL. However, you can link individual tables. A federated table is a local table you create that points to a table on another server.
You can run queries and stored procedures just like any other table. The two tables must have the same structure, except the Federated table uses a different database engine: Federated. If you make ANY changes to the structure of the remote table, you should re-create the local federated table.
The process is actually quite easy, here is an example: https://docs.oracle.com/cd/E17952_01/mysql-5.0-en/federated-use.html
In my experience, the time needed to create and implement this process is minimal, even when compared to linked servers. It should take you less than 30 minutes to get your first federated table working, after that its a 5 min process. Last item, when naming your federated table, I give it the same name as the remote table with a "federated_" in front, like federated_customer.
Also, store your federated table definitions as separate stored procedures so you can reuse them anytime you need to create the federated table again, AND so that other developers can see how you generated the federated table.
The MySQL Data Controller is a follow-on to the federated engine that allows connection to different database types, such as Microsoft SQL Server or Oracle. I am not sure how development is going, yet.
See: http://en.wikipedia.org/wiki/MySQL_DataController
or: https://launchpad.net/datacontroller
Is it possible to link tables from other databases (MS SQL, Sybase, etc.) inside a MySQL database, on a Debian server?
I am thinking this could be possible using ODBC.
Out of the box, I don't think so.
AFAIK, while its possible to implement your own functions in MySQL, these can only return single values - not tables of data.
It should be possible using a custom storage engine plugin. I believe there's one written for DB2 but a quick google turned up nothing for ODBC. It'd be a useful thing to have - so you could write one.
The only caveat is that neither the local MySQL nor the remote ODBC connected database would be able to optimise queries spanning engines properly - so it might be more efficient to handle the two systems in a progrmanning language which supports both.
If I recall correctly, there where at least to desktop programas from sun which were very useful for handling mysql databases...
Now, all I can find is some mysql workbench which is only useful for designing data...
Both programs I'm talking about allowed you to manage servers, create database, create tables, index, perform querys, edit data, etc...
unfortunately I don't even recall their names...
Any idea where I can find them?
thanks a lot
Are you talking about MySQL GUI Tools?
They represent a set of applications for the administration of MySQL database servers, and for building and manipulating the data within MySQL databases.