How to Enable Data Truncation in MySQL without Generating Errors?

MySQL Data Truncation and Error Handling

In MySQL, handling data that exceeds column length limits can vary between instances. In some cases, excessive data is truncated without generating errors, while in others, an error is raised. This question explores the MySQL setting that enables data truncation in specific scenarios.

Problem Statement:

Two MySQL instances exhibit different behavior when inserting data that exceeds the allowed length: one truncates the data, while the other raises an error. The question seeks a solution to modify the errant instance to truncate the data as well.

Solution:

To enable automatic truncation of long strings during data insertion, MySQL offers the following settings:

• STRICT_TRANS_TABLES: Controls truncation behavior within a transaction.
• STRICT_ALL_TABLES: Controls truncation behavior across all tables.

Disabling these settings allows MySQL to automatically truncate inserted strings, resolving the behavior difference between the two instances.

MySQL Documentation Excerpt:

"Strict mode controls how MySQL handles invalid or missing values in data-change statements such as INSERT or UPDATE...A value can be invalid for several reasons. For example, it might have the wrong data type for the column, or it might be out of range. A value is missing when a new row to be inserted does not contain a value for a non-NULL column that has no explicit DEFAULT clause in its definition."

Reference:

• [MySQL Server SQL Modes](https://dev.mysql.com/doc/refman/8.0/en/sql-mode.html)

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