IJC-Multi User problem

User 0e345a0616

23-09-2011 07:12:00

I tried to connect to a MySQL database installed in my machine... I am facing with the following issues.

Could you please help me in solving my Queires:

I am attaching the screen shots of the errors.

ChemAxon fa971619eb

23-09-2011 07:30:38

Hi, could you provide some additional information:

1. the version of MySQL that you are using

2. the full text of the error message for images 1 and/or 3.



User 0e345a0616

23-09-2011 08:37:23

I am using MySQL 4.1.12  


I have attached the text file of the error.

ChemAxon fa971619eb

25-09-2011 08:05:38

Hi, that error seems to be related to JChem Manager, not Instant JChem.

Could you describe what you are doing to get this?


ChemAxon fa971619eb

25-09-2011 08:18:31

Another thing, the admin docs for IJC state that MySQL 5 versions are tested.

Its not clear that MySQL 4 will work correctly, and we cannot support such an untested version. I suggest you switch to using MySQL 5.


User 421219f4d4

27-09-2011 03:46:12

Hello Tim,


We have upgraded the MySQL server and now its connecting to the database. Right now we are facing the following error. whenever we try to connnect to the host database through a client machine it gives the error 

Could not get JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Commmunication link faliure


I have attached a screnshot of the error.

ChemAxon fa971619eb

27-09-2011 04:39:44

Please could you send the information in the log file after you get the error. You can see the log file using:
View -> Instant JChem Log file.
If you could save the full contents to a file and attach it to this forum topic then we should be able to see the actual cause of the error.


User 0e345a0616

27-09-2011 08:22:05

hello sir


plz find the attached instant jchem log file

User 0e345a0616

28-09-2011 06:15:37

I am waiting for the reply

ChemAxon e189db4705

28-09-2011 09:31:13

From the log file it is still not clear what is causing the errors.

In one of previous comments you mentioned that now you can connect to database ("We have upgraded the MySQL server and now its connecting to the database..."), but then you wrote that you can't connect from client machines ("...whenever we try to connnect to the host database through a client machine it gives the error").

Does it mean that you can connect from a machine where DB is installed, but you can't connect from any other machine?

We think that firewall can be involved somehow. Could you try to connect from a client machine to database using e.g. MySQL administrator console and try to look at tables, data, etc.?


User 421219f4d4

28-09-2011 09:55:21

Thanks for the reply.....

Yes you got it correct.... we can access the database from the machine in which it is installed.... but not from other client machines.

Will check the firewall status and let you know.

By The way so we need to copy any .jar files that are not there by default. As in mysql connector or JDBC connector?

I have attached a screenshot of the files that are present in my Java folder. Am I missing any file that might cause the error?

ChemAxon e189db4705

28-09-2011 10:47:29

You don't need to copy any individual jars which are part of java installation.

I meant MySQL administrator console - which is standalone application and it should have all required components (jars) part of its installation. I think only thing you need to verify the firewall potential problem is to install MySQL Workbench (http://dev.mysql.com/downloads/workbench/5.2.html) or older MySQL Administrator (if you have previous version of MySQL)... and try to connect to server from other machine.

User 791c148e8a

28-09-2011 11:20:53

Default configuration for MySQL only allows root access from a local host machine. There are plenty of resources on web where you can find how to enable this access from other machines as well. For example here is a link to one of the first Google results to 'mysql access from any host' - http://slaptijack.com/software/mysql-gotcha-remote-root-access/


User 0e345a0616

29-09-2011 11:49:45

hello sir

As from your previous message, i have checked the link which u hv sent me and i have followed that mysql granted commands...but again getting the same jdbc error

ChemAxon e189db4705

29-09-2011 12:11:14

Just to be sure: you are able to connect to server using MySQL Administrator (or MySQL Workbench) from a different machine to MySQL server, right? And then you can browse tables, see data, etc?

And you are able to connect to database from IJC running on the same machine as MySQL server (means connect, see forms, run queries, etc) ?

It is still not sure whether this is a network problem or some issue with IJC schema.

User 421219f4d4

04-10-2011 07:53:05

Dear Petr,

Thanks for the support, The problem is solved now. The basic error was MySQL/IJC versions that we were using.