大型 VARCHAR vs. TEXT？

Question

I've got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserted into the db as longer than this.

Is there a rationale for going with either VARCHAR(3000) or TEXT? There's something about just writing VARCHAR(3000) that feels somewhat counter-intuitive. I've been through other similar posts on Stack Overflow but would be good to get views specific to this type of common message storing.

转载于:https://stackoverflow.com/questions/2023481/mysql-large-varchar-vs-text

Answer 1

• TEXT and BLOB is stored off the table with the table just having a pointer to the location of the actual storage.

• VARCHAR is stored inline with the table. VARCHAR is faster when the size is reasonable, the tradeoff of which would be faster depends upon your data and your hardware, you'd want to benchmark a realworld scenario with your data.

Update Whether VARCHAR or TEXT is stored inline, or off-record depends on data size, columns size, row_format, and MySQL version. It does not depend on "text" vs "varchar".