[NIFI-3742] PutDatabaseRecord can not delete row if it contains null value

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.0
• Fix Version/s: 1.2.0
• Component/s: Extensions
• Assignee: Matt Burgess
• Reporter: Koji Kawamura
• Created: 26/Apr/17 12:56
• Updated: 11/May/21 08:56
• Resolved: 28/Apr/17 02:38

Description

For example, let's say a table which has null-able columns. When rows get deleted, CaptureChangeMySQL emits 'delete' events for each deleted row with all column values including null-able ones. From those data, PutDatabaseRecord can generate delete statements for other table which have where clause like this:

DELETE FROM users WHERE id = 4 AND title = null AND first = 'Koji' AND last = 'Kawamura' AND street = null AND city = null AND state = null AND zip = null AND gender = null AND email = null AND username = null AND password = null AND phone = null AND cell = null AND ssn = null AND date_of_birth = null AND reg_date = null AND large = null AND medium = null AND thumbnail = null AND version = null AND nationality = null

However, a condition like 'title = null' doesn't hit with any record, because for null value, we should use 'title IS null' instead.
I think we should do something like below in order to treat these null-able columns:

# With a prepared statement like this:
DELETE FROM users WHERE id = ? AND (title = ? OR (title is null AND ? is null)) AND ... so on ...;
# Which is executed like this:
DELETE FROM users WHERE id = 4 AND (title = null OR (title is null AND null is null)) … and so on …;

Reference:
http://stackoverflow.com/questions/4215135/how-to-deal-with-maybe-null-values-in-a-preparedstatement

Issue Links

• causes: NIFI-8530 PutDatabaseRecord DELETE issue with Postgres UUID
• links to: GitHub Pull Request #1709