Hello,
I am trying to migrate a fully published issue from one OJS portal to another OJS portal.
Environment
- OJS Version: 3.4.0-9 (same version on both source and destination portals)
- Database: MySQL
- Migration type: Import by Native XML Plugin
Error encountered during import
During the import of the issue, the process fails with the following database error:
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`ojs34`.`publications`, CONSTRAINT `publications_primary_contact_id` FOREIGN KEY (`primary_contact_id`) REFERENCES `authors` (`author_id`) ON DELETE SET NULL) (SQL: update `publications` set `access_status` = 0, `date_published` = 2025-06-20, `last_modified` = 2026-01-15 09:20:16, `primary_contact_id` = 0, `section_id` = 264, `seq` = 1, `submission_id` = 174357, `status` = 3, `url_path` = ?, `version` = 1, `doi_id` = 20827 where `publication_id` = 151863)
- The error is caused by
primary_contact_id = 0
- In the destination database, there is no author with
author_id = 0
Any guidance, best practices, or references would be highly appreciated.
Hi @shantanusingh!
I see room for failure on the code, do you have a sample XML to provide? It can be with anonymized data, I’d just like to see the content of the <authors> node.
Best,
Jonas Raoni
Hi @jonasraoni Thanks for reply
Please refer to this link for the XML file.
Hi @shantanusingh,
I could import this XML without any issues on my environment, this leads me to believe you might be having problems with the charset/collation. Are you using the charset utf8mb4?
Do you see more error messages on the error log appearning before this one that I can see on the screenshot?
Best,
Jonas Raoni
Hi @jonasraoni
After running the SQL query SHOW CREATE DATABASE database; the result shows /*!40100 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci */
Just I have tried to new setup but same issue appeared.
No error log generated for this. Only show below error on OJS application.
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`ojs3409`.`publications`, CONSTRAINT `publications_primary_contact_id` FOREIGN KEY (`primary_contact_id`) REFERENCES `authors` (`author_id`) ON DELETE SET NULL) (SQL: update `publications` set `access_status` = 0, `date_published` = 2025-06-20, `last_modified` = 2026-04-09 13:36:20, `primary_contact_id` = 0, `section_id` = 40, `seq` = 1, `submission_id` = 11, `status` = 3, `url_path` = ?, `version` = 1, `doi_id` = 10 where `publication_id` = 11)
This is the charset/collation of the database, MySQL allows you to have tables with different charsets/collations too, you can run this query to check if this is your case (just replace the NAME_OF_YOUR_DATABASE by your database name):
SELECT table_name, table_collation
FROM information_schema.tables
WHERE table_schema = ‘NAME_OF_YOUR_DATABASE’
AND table_collation != ‘utf8mb4_0900_ai_ci’;
If everything is ok at this point and you have no other errors on the log, then it will be require some debugging 
Best,
Jonas Raoni
here is the result and it shows utf8mb3_general_ci with 166 rows.
Hmm, so let’s try to update the charset/collation, the utf8mb4 is basically an extension (supports more characters) of the utf8mb3.
The query below should generate a bunch of ALTER TABLE … commands, you can copy everything and execute (again, update YOUR_DATABASE_NAME by the name of your database) 
SELECT CONCAT('ALTER TABLE `', table_name, '` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci;')
FROM information_schema.tables
WHERE table_schema = 'YOUR_DATABASE_NAME' AND table_collation != 'utf8mb4_0900_ai_ci';
Best,
Jonas Raoni
Hi @jonasraoni
Thanks for your excellent guidance every time, but I have a doubt, because of the huge database (20 GB) it may take a lot of time to execute, which might be risky.
Oh, I see… This isn’t a requirement, but whenever a user attempt to use an unsupported character, it will lead an error in the database.
I’m not completely sure this is causing the issue, but as you don’t have a helpful error and I can’t simulate it on my environment, then it will require a “poor man’s debugging” (removing any error protection and/or place checks on the code to understand where it’s stopping).
Best,
Jonas Raoni
