How to Handle Duplicate Keys in SQL Inserts: INSERT IGNORE vs. ON DUPLICATE KEY UPDATE?

Avoid INSERT IGNORE for Duplicate Key Handling

To prevent duplicate tags from interfering with data insertion, it's essential to implement proper error handling strategies. While the temptation to use INSERT IGNORE may arise, it's critical to understand its limitations.

Drawbacks of INSERT IGNORE

INSERT IGNORE ignores errors indiscriminately, which can lead to data integrity issues. This behavior is inappropriate for scenarios where duplicate keys should be considered.

Preferred Approach

Instead of using INSERT IGNORE, consider utilizing ON DUPLICATE KEY UPDATE. This approach allows you to specify actions to be taken when a duplicate key is encountered. In the case of unique tags, you can update the existing tag value.

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

Example Output

This query will insert new tags or update existing ones, depending on whether the tag is unique or not:

Query OK, 0 rows affected (0.07 sec)

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