Hey everyone! I’m working on a project where I need to upload data from Excel to a MySQL database. The tricky part is that I need to check for duplicates before inserting new records. The main table already has about 2.5 million rows, so it needs to be super fast.
I thought about adding a hashcode field to the table. When inserting new records, I’d calculate a hashcode for each row. Then, to check for duplicates, I’d just compare the hashcodes. If a hashcode already exists in the main table, it’s a duplicate. If not, it’s unique.
But I’m not sure if this is the best way to do it. Does anyone know if MySQL has any built-in features or tricks to handle this kind of thing more efficiently? I’m pretty new to MySQL, so I’d love to hear about any clever solutions you might have!
Thanks for your help!
Having dealt with similar scenarios, I can suggest a few efficient approaches. Firstly, consider using a composite unique index on the columns that define uniqueness. This allows MySQL to quickly identify duplicates during insertion. Alternatively, you could implement a staging table strategy. Load new data into a temporary table, then use SQL to identify and insert only unique records into the main table. This method is particularly effective for bulk operations. Lastly, if you’re dealing with frequent, smaller updates, look into using INSERT … ON DUPLICATE KEY UPDATE statements. This allows MySQL to handle duplicates in a single query, significantly improving performance for large datasets.
Ooh, interesting problem! Have you thought about using a temporary table for new data? You could compare it with the main table using JOIN operations. might be faster than individual checks. What kind of data are you dealing with? Any specific fields that usually indicate uniqueness?
hey ryan, ur hashcode idea ain’t bad but it might cause collisions. have u tried using a unique index on the important columns? it’s pretty fast and mysql handles it natively. also, u could do batch inserts with IGNORE to skip dupes. just make sure ur index covers the right fields!