On Mon, 14 Jun 2010, Michael Dykman wrote:
11 characters of display allow for any int of any size, signed or
unsigned. When you do not specify a length attribute in a
declaration, MySQL uses 11 as the default.
As an astrophysicist, I've always considered a flaw the fact that mysql
(or SQL in general ?) mix up things like the number of bytes taken by a
quantity, and the number of digits recommended for display.
In our parliance (e.g. the FITS data format used by the International
Astronomical Union for data exchange) this is mixing up TTYPE (e.g. 8- 16-
or 32- bit integers, 32- or 64-bit floats) and TDISP (the Fortran-like
format suggested for display).
In mysql I always use the generic type (int or float or double, rarely
things like bigint or tinyint) for numeric quantities, without any
number-of-digit indication.
For floats they are not just used for display, but sometime affect also
comparison and that's very annoying if you work usually with numbers like
1.43E-12 !
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