Tutorial 830 foreign key constraint fails

[#1]

Hi,

I am following the tutorial 830 which implements the trucking example app on the HDF 3.0 sandbox. https://hortonworks.com/tutorial/real-time-event-processing-in-nifi-sam-schema-registry-and-superset...

Problem One

The tutorial itself does not have a commenting system associated with it. It suggests we use this platform. Except that the "Find Answers" link is not correct and it recommends using the tags "tutorial-830 and hdf-3.0.0" which I cannot create.

Problem Two

I am getting a foreign key constraint problem when importing the example SAM application from the supplied JSON.

Can anyone confirm if this is a problem with the tutorial or whether I have done something wrong?

Thanks... The exception on screen seems to be as follows:

   An exception with message [com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`streamline`.`topology`, CONSTRAINT `topology_ibfk_1` FOREIGN KEY (`versionId`) REFERENCES `topology_version` (`id`))] was thrown while processing request.   

[#2]

Problem one appears to be a documentation bug that needs to be corrected. As to problem two, I ran into the same issue while setting it up, and I ended up having to temporarily disable the foreign key checks on the MySQL instance that SAM connects to:

1. Inside the MySQL command prompt, run 'SET FOREIGN_KEY_CHECKS=0;'

2. Import the app .json template

3. Inside the MySQL command prompt, run 'SET FOREIGN_KEY_CHECKS=1;'

Hope that helps.

[#3]

It is really helpful to know it wasn't me messing up. I can switch off foreign key restraints temporarily as you suggest. Thanks!

[#4]

Your welcome, please don't forget to 'accept' the answer if it works!

[#5]

Further to dsun's reply, here are the implementation steps:

1) login to the HDF sandbox (default password is hadoop)

ssh -p 12222 root@localhost

2) login to the mysql console (default password is also hadoop)

[root@sandbox-hdf streamline]# mysql streamline --user=root -p
Enter password:
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 488
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

3) set the global foreign_key_checks variable to off:

mysql> set @@global.foreign_key_checks=off;
Query OK, 0 rows affected (0.00 sec)

4) restart SAM on the ambari console

5) add the application as per the original tutorial.

,

Further to dsun's answer, here are the commands to apply the recommended solution:

# Login as root to the hdf sandbox (ssh -p 12222 root@localhost) <default pwd is hadoop># run the following (default pwd is also hadoop>mysql streamline --user=root -p

Enter password: hadoop

Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Welcome to the MySQL monitor.  Commands end with ; or \g. Your MySQL connection id is 488 Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. 

mysql> set @@global.foreign_key_checks=off;
Query OK, 0 rows affected (0.00 sec)

Then, restart SAM from the ambari console, and try again.