mysqldump --replace flag

The mysqldump command has a --replace flag that can be used to generate REPLACE INTO statements instead of INSERT INTO statements in the SQL script.

REPLACE INTO statements are similar to INSERT INTO statements, but if a row already exists with the same primary key or unique index, the REPLACE INTO statement will delete the old row and insert a new one in its place. If the row does not exist, it will be inserted as a new row.

Here is an example of how to use the --replace flag:

mysqldump my_app --replace > my_backup.sql

This will create a my_backup.sql SQL file with REPLACE INTO statements instead of INSERT INTO.

When to use the --replace flag?

The --replace flag can be useful if you want to update existing rows with new data.