Error
Error Code:
1391
MariaDB Error 1391: Invalid Key Part Length
Description
Error 1391 indicates that a key component, often a column prefix within an index or a part of a foreign key, has been defined with a length of zero. This typically occurs during `CREATE TABLE` or `ALTER TABLE` operations when defining indexes, particularly on `TEXT` or `BLOB` columns, or when specifying foreign key constraints.
Error Message
Key part '%s' length cannot be 0
Known Causes
3 known causesExplicit Zero Length in Index
A `CREATE INDEX` or `ALTER TABLE` statement explicitly specifies a column prefix length of `0` for a key part, which is invalid.
Missing or Invalid Prefix Length
When creating an index on `TEXT` or `BLOB` columns, a required prefix length was omitted or incorrectly formatted, leading to an implied zero length.
Foreign Key Definition Error
Defining a `FOREIGN KEY` constraint where the referenced or referencing column part implicitly or explicitly has a zero length, which is not permitted.
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