tiflash: MySQL compatibility about decimal insert through jdbc

[ChangRui-Ryan]

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• This PR is translated from:tiflash: MySQL compatibility about decimal insert through jdbc docs-cn#20786
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• Delete files
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[pingcap-cla-assistant]

All committers have signed the CLA.

[gemini-code-assist]

Summary of Changes

Hello @ChangRui-Ryan, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the documentation for TiDB's JDBC application guide by clarifying its compatibility with MySQL regarding DECIMAL data type insertions. The update provides important information on how TiDB handles DECIMAL values with excessive precision, ensuring users understand the consistent truncation behavior introduced in recent versions to match MySQL's functionality.

Highlights

• Documentation Update for MySQL Compatibility: A new section titled "MySQL compatibility" has been added to the develop/dev-guide-sample-application-java-jdbc.md file. This section details how TiDB handles DECIMAL type data insertions when the number of decimal places exceeds the field's defined limit. It specifically highlights that, starting from TiDB v8.1.3, the system's behavior now aligns with MySQL, performing a truncation and successful insertion regardless of the excess decimal places.

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[gemini-code-assist]

Code Review

This pull request adds documentation about a MySQL compatibility change related to DECIMAL type insertion. The explanation is clear, but I have provided one suggestion to improve the wording and formatting to better align with the documentation style guide. Specifically, my suggestion uses the second person, adds backticks for code elements, and improves clarity.

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[APPROVALNOTIFIER] This PR is NOT APPROVED

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[ChangRui-Ryan]

/test pull-verify

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-08-29 01:21:10.034779023 +0000 UTC m=+489561.912609977: ☑️ agreed by hfxsd.