Duplicate Keys: Ignore or Update?

Overcoming Duplicate Key Errors: Ignoring or Updating?

When working with unique keys, it's common to encounter situations where duplicate entries may arise. If you want to handle these duplicates gracefully, you may consider using either INSERT IGNORE or ON DUPLICATE KEY UPDATE.

If your goal is to simply ignore duplicate tags and continue inserting subsequent ones, using INSERT IGNORE may seem like a suitable option. However, it's worth noting that INSERT IGNORE disregards all errors, which may lead to potential data integrity issues.

A more recommended approach is to employ ON DUPLICATE KEY UPDATE together with the unique key. In your case, tag is the unique key. The following query demonstrates how to achieve this:

INSERT INTO table_tags (tag) VALUES ('tag_a'),('tab_b'),('tag_c')
ON DUPLICATE KEY UPDATE tag=tag;

By using this approach, the database will update the existing tag with the new value, preventing duplicate entries. Upon successful execution, you should receive a query output similar to:

Query OK, 0 rows affected (0.07 sec)

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