Error
Error Code:
3939
MySQL Error 3939: Duplicate Constraint Names
Description
This MySQL error indicates that you are attempting to create or modify a table in a way that would result in multiple constraints (such as PRIMARY KEY, UNIQUE, FOREIGN KEY, or CHECK constraints) sharing the exact same name within that table. MySQL requires all constraint names within a single table to be unique for proper management and identification.
Error Message
Table has multiple constraints with the name '%s'. Please use constraint specific '%s' clause.
Known Causes
4 known causesExplicit Duplicate Constraint Definition
Attempting to define two or more constraints (e.g., PRIMARY KEY, UNIQUE, FOREIGN KEY) with identical names within a single CREATE TABLE or ALTER TABLE statement.
Repeated DDL Script Execution
Executing data definition language (DDL) scripts multiple times without proper cleanup, leading to attempts to re-create constraints that already exist or would result in name collisions.
Copy-Paste DDL Errors
Copying and pasting DDL statements for different constraints and inadvertently failing to update the constraint names, leading to unintended duplicates.
Schema Migration Tool Conflict
Automated schema migration tools or scripts might inadvertently generate or apply DDL that results in duplicate constraint names if not configured correctly or if existing schema conflicts.
Solutions
Coming SoonDetailed step-by-step solutions for this error are being prepared. In the meantime, try these general troubleshooting tips:
General Troubleshooting Tips
- Check the error message carefully for specific details
- Review recent changes that might have caused the error
- Search for the exact error code in the official documentation
- Check log files for additional context
- Try restarting the application or service