Shulou(Shulou.com)06/01 Report--

I. Description

How to choose the data type of channel number, two choices, one is char(), the other is varchar(). In the system to see what has been used, there is no rule, there is no way out of the need to develop a specification, disable char().

II. Reasons

1. Char expansion will cause table locks, which will affect business.

Varchar extension does not rebuild tables within 255, nor does it generate lock tables, which does not affect business.

3, especially similar to channel (3) channel number must use varchar data type.

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