I noticed that in MySQL, both VARCHAR and TEXT offer variable-sized data. Well, VARCHAR is a bit more efficient in data storage, but still, TEXT MEDIUMTEXT and LONGTEXT offer a lot more potential. So, what are the real uses of VARCHAR?
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First of all, you should read the 10.4. String Types section of the MySQL's manual : it'll give you all the informations you are looking for :
A couple of important differences :
- Difference in the amount of text those can contain :
- varchar have a quite small size limit ; with the newest versions of MySQL, it's 64 KB, for the total of all varchar columns of a row -- which is not that much.
- TEXT have virtually no limit, as they can contain something like 2^32 bytes.
- There are differences in indexing and sorting, if I'm not mistake ; quoting the page about TEXT :
- About sorting : "Only the first
max_sort_lengthbytes of the column are used when sorting." - And, about performances : "Instances of BLOB or TEXT columns in the result of a query that is processed using a temporary table causes the server to use a table on disk rather than in memory"
- About sorting : "Only the first
Considering these informations, if you are sure that your strings will not be too long, and that you'll always be able to store them in a varchar, I would use a varchar.
