Support JDBC driver for iSeries DB2

[V3lop5]

I found this framework recently and want to use it in combination with an iSeries / AS400 DB2 database.
Unfortunately, I couldn't get it to work with the required JDBC driver jt400.

What have I done?
I used the jt400 driver with Exposed Spring Starter. The error message Unsupported driver AS / 400 Toolbox for Java JDBC Driver detected appeared during the first transaction.

 <!-- https://mvnrepository.com/artifact/net.sf.jt400/jt400 -->
    <dependency>
      <groupId>net.sf.jt400</groupId>
      <artifactId>jt400-jdk8</artifactId>
      <version>10.3</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.jetbrains.exposed/exposed-spring-boot-starter -->
    <dependency>
      <groupId>org.jetbrains.exposed</groupId>
      <artifactId>exposed-spring-boot-starter</artifactId>
      <version>0.25.1</version>
    </dependency>

For this reason, I created a PULL request that supports the JDBC driver jt400 and at the same time adds the DB2 dialect.

[Tapac]

Could you please add db2 into TestDB to check that dialect works correctly?

[V3lop5]

Hello Tapac,
thanks for your reply.

Currently I'm working on my bachelor thesis and running low on time.
I'll finish the tests later on.

[V3lop5]

I'm still alive! Currently I'm trying to get the db2 tests running.

There are two main versions of db2 out there: LUW and as400 (or called "i series" in modern references. But it's an ibm product so "modern" does not apply)
Originally my PR targeted the second one.
But testing the second one is really hard because you need such a midrange server.

So i decided to add LUW support to. The dialect is as far as i know the same. (But all system functions and tables are named differently for extra fun when searching/reading the docs.) The required jdbc driver can be found here (i guess).

Currently I ran into this jdbc connection problem. I tested multiple jdbc drivers but no one seems working out of the box.

I will pick up my work later on but for now i pushed my half working version of db2 tests. Maybe somebody finds a solution and can fix this. 🐧

[Tapac]

@V3lop5 , I was able to run db2 tests but most of them fail. Please apply my patch and then try to fix them as I don't know the DB2 syntax.

[sola1tmy]

I'd like to add DB2 implementation based on the newly found db2 driver. However, this PR is exist now but hasn't been reviewed or merge for a long time. Shall I open a new PR or create a PR in @V3lop5 fork?

[V3lop5]

Hi @sola1tmy, I'm still alive but got no time to finish my work here.

This PR is not merged due to failing tests.

[sola1tmy]

@V3lop5 So maybe I should create a pull request in your fork.
Now I'v fix some tests but there are still about 30 failed tests.Unluckily I won't have time to fix them this week.
Emm.Something more deserve to say is that a group_concat test failed seems to be a db2 bug, it may can't be fixed in exposed.

[sola1tmy]

And, the right driver should be com.ibm.db2:jcc:11.5.60

[V3lop5]

@V3lop5 So maybe I should create a pull request in your fork. Now I'v fix some tests but there are still about 30 failed tests.Unluckily I won't have time to fix them this week. Emm.Something more deserve to say is that a group_concat test failed seems to be a db2 bug, it may can't be fixed in exposed.

Great! I missed your message and merged the JetBrains-master into my fork.
Hopefully that works for you?

And, the right driver should be com.ibm.db2:jcc:11.5.60

The latest version I see is 11.5.7.0.

Now you should noew be able to run db2 tests using ./gradlew db2Test in root folder.

Console output:

[...]
24 tests completed, 21 failed, 3 skipped

> Task :exposed-java-time:db2Test FAILED

FAILURE: Build failed with an exception.

I'm sorry for that many failing tests.
I originally created this PR with the intention to support data query language for DB2 AS/400. A frozen clone of my fork is still in use. I suppose.

I'll await your fixes and might be able to resolve the other failing tests next week.