[FLINK-37834] Flink JDBC support ClickHouse Dialect

[Biasqo]

🔌 ClickHouse Dialect for Flink Link JDBC Connector

This project provides a ClickHouse SQL dialect implementation for the Apache Flink JDBC Connector.

🚀 Purpose
Apache Flink’s Link JDBC connector offers a flexible way to integrate with relational databases through dialects. However, native support for ClickHouse’s SQL features (e.g. merge trees, upserts, batch writes) is limited in SQL CLI.

✨ Features
✅ Custom ClickHouseDialect integration
✅ Column quoting and identifier case sensitivity fixes
✅ Insert/update query support tailored for ClickHouse (pkFields removed from update statement)

TODO:
Refactor Tests: Some methods are private (like getStreamFields() that's why I had to recreate some test classes)

Jira Issue:
https://issues.apache.org/jira/projects/FLINK/issues/FLINK-37834

[Biasqo]

@eskabetxe could you please start CI or review PR?

[eskabetxe]

Thanks for your contribution, I can't start CI/CD sorry. @1996fanrui can you start it?

I review the main code and left minor comments.
I dont review the tests as you have a TODO to some refactoring there.

You also need to add this module on flink-connector-jdbc-architecture.

[eskabetxe]

the changes in this file should be reverted

[eskabetxe]

Why not use the last version available 0.8.6?

[Biasqo]

@eskabetxe
Thanks for getting back to me

1. I’m using version 0.6.2 since 0.8+ has some dependency issues with httpcore, and I didn’t want to change the existing httpcore version. If it’s okay to upgrade some of the libraries already included in the distribution, I can go ahead and fix it.
2. I will revert .vcs
3. About the tests: I’m not sure if I can override some private methods that are part of abstract test classes (for example, the abstract class TableBase, method getStreamFields). If I’m allowed to make them protected, the number of test classes could be significantly reduced. Clickhouse has its unique create statement - that's why it was a problem

[Biasqo]

Thanks for your contribution, I can't start CI/CD sorry. @1996fanrui can you start it?

I review the main code and left minor comments.

I dont review the tests as you have a TODO to some refactoring there.

You also need to add this module on flink-connector-jdbc-architecture.

Is it okay if I refactor some of the core classes in the tests, like making them protected?

[eskabetxe]

@eskabetxe Thanks for getting back to me

1. I’m using version 0.6.2 since 0.8+ has some dependency issues with httpcore, and I didn’t want to change the existing httpcore version. If it’s okay to upgrade some of the libraries already included in the distribution, I can go ahead and fix it.
2. I will revert .vcs
3. About the tests: I’m not sure if I can override some private methods that are part of abstract test classes (for example, the abstract class TableBase, method getStreamFields). If I’m allowed to make them protected, the number of test classes could be significantly reduced. Clickhouse has its unique create statement - that's why it was a problem

Its ok to bump some versions and is ok also change some test methods from private to protected if you need to override them..

[Biasqo]

Ive refactored tests but cannot use click house driver version 0.7+ since click house testcontainers support 0.6.2.
Clickhouse driver dependency is only needed for tests