Why Does My MySQL LOAD_FILE Function Fail to Load Blobs?

Troubleshooting LOAD_FILE for MySQL Blob Loading

Attempts to utilize LOAD_FILE to load a file into a MySQL blob may encounter issues, as demonstrated in the following query:

INSERT INTO MyTable VALUES('7', LOAD_FILE('Dev:MonDoc.odt'))

While no error is apparent, the file fails to load into the blob. To resolve this issue, it is crucial to adhere to the conditions outlined in the MySQL documentation:

• File Location: The file must reside on the server host, and its full path must be specified.
• File Permissions: The file must be readable by all, and its size must be less than max_allowed_packet bytes.
• System Variable Setting: If the secure_file_priv system variable is configured with a nonempty directory name, the file must be situated within that directory.
• File Existence: If the file does not exist or is inaccessible due to permission issues, the function will return NULL.
• Usage Example: The correct syntax, as provided in the manual, should be as follows:

UPDATE t
SET blob_col=LOAD_FILE('/tmp/picture')
WHERE>

To troubleshoot the issue in your specific case, consider the following:

• Ensure you are providing the complete file path, including all necessary directory levels.
• Verify that appropriate permissions are granted to allow file access.
• Examine the function's return value; a NULL result indicates an issue with file access or availability.
• Attempt the query provided in the manual to determine if other factors may be influencing the behavior.

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