Feature Request : Configuration Change for Auto-generation Target Tables(with Postgres)

[Naka Sho]

While there is an option to release a custom plugin to resolve issues specific to Postgres, I believe it would be more likely to be used if it was included in the main body.

Currently, it requires the following steps:
1. Automatically generate config.xml
2. Delete from the automatically generated file

So I think a plugin would be a better solution.

I have created the following.
If there are no problems, please consider introducing it in the next version.

https://github.com/mybatis/generator/issues/1353

# Description

Adds SkipPartitionedWithPostgresTablesPlugin, a MyBatis Generator (MBG) plugin that skips generating artifacts (model classes, mappers, dynamic SQL support) for PostgreSQL partition child tables. It discovers all non-partition-child tables plus views (excluding pg_catalog and information_schema) and only generates code for those. Optionally writes the allowlist to a file. Supports case-insensitive matching.

# Background

PostgreSQL declarative partitioning creates a physical table for every partition. Generating MyBatis artifacts for each child partition leads to:
 - A large number of nearly identical classes/mappers
 - Churn when time-based partitions rotate
 - Redundant code when logic works at the parent level or routing is external

This plugin:

 - Queries PostgreSQL system catalogs (pg_inherits, pg_class, pg_tables, pg_views)
 - Excludes partition child tables
 - Keeps normal tables, partition parent tables, and views
 - Fails fast (throws RuntimeException) if discovery or writing the allowlist fails

# Usage
Add the plugin inside an MBG <context> that has a PostgreSQL connection (either jdbcConnection or connectionFactory).

 - Available properties:
   - allowlistFile (optional): file path to write the discovered (sorted) table/view names
   - caseInsensitive (optional, default false): perform case-insensitive matching

Example:
```xml
<context id="PostgresContext" targetRuntime="MyBatis3">
  <jdbcConnection driverClass="org.postgresql.Driver"
                  connectionURL="jdbc:postgresql://localhost:5432/appdb"
                  userId="app"
                  password="secret"/>

  <plugin type="org.mybatis.generator.plugins.SkipPartitionedWithPostgresTablesPlugin">
    <property name="allowlistFile" value="build/mbg/allowlist.txt"/>
    <property name="caseInsensitive" value="true"/>
  </plugin>

  <!-- Optional <table> elements. If omitted, MBG introspects all; the plugin filters afterward. -->
</context>
```

# Behavior summary:
 - Discovers non-partition-child tables (excludes system schemas)
 - Adds views (non-system schemas)
 - Builds in-memory allowlist (+ optional file write) -
 - Skips generation for anything not in the allowlist
 - Runtime exception on any discovery or write failure

# Limitations / Notes:
 - Partition parent tables are still included
 - No custom schema include/exclude yet (only system schemas excluded)