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manual.texi Added note about retrieving ENUM or SET column values

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manual.texi	as numbers by adding +0 to the column name.


Docs/manual.texi:
  Added note about retrieving ENUM or SET column values
  as numbers by adding +0 to the column name.
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unknown 2000-10-13 17:25:51 -05:00
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@ -14145,11 +14145,18 @@ Lettercase is irrelevant when you assign values to an @code{ENUM} column.
However, values retrieved from the column later have lettercase matching the
values that were used to specify the allowable values at table creation time.
If you retrieve an @code{ENUM} in a numeric context, the column value's index
is returned. If you store a number into an @code{ENUM}, the number is
treated as an index, and the value stored is the enumeration member with
that index. (However, this will not work with @code{LOAD DATA}, which treats
all input as strings.)
If you retrieve an @code{ENUM} in a numeric context, the column value's
index is returned. For example, you can retrieve numeric values from
an @code{ENUM} column like this:
@example
mysql> SELECT enum_col+0 FROM tbl_name;
@end example
If you store a number into an @code{ENUM}, the number is treated as an
index, and the value stored is the enumeration member with that index.
(However, this will not work with @code{LOAD DATA}, which treats all
input as strings.)
@code{ENUM} values are sorted according to the order in which the enumeration
members were listed in the column specification. (In other words,
@ -14189,11 +14196,18 @@ A @code{SET} can have a maximum of 64 different members.
@strong{MySQL} stores @code{SET} values numerically, with the low-order bit
of the stored value corresponding to the first set member. If you retrieve a
@code{SET} value in a numeric context, the value retrieved has bits set
corresponding to the set members that make up the column value. If a number
is stored into a @code{SET} column, the bits that are set in the binary
representation of the number determine the set members in the column value.
Suppose a column is specified as @code{SET("a","b","c","d")}. Then the
members have the following bit values:
corresponding to the set members that make up the column value. For example,
you can retrieve numeric values from a @code{SET} column like this:
@example
mysql> SELECT set_col+0 FROM tbl_name;
@end example
If a number is stored into a @code{SET} column, the bits that
are set in the binary representation of the number determine the
set members in the column value. Suppose a column is specified as
@code{SET("a","b","c","d")}. Then the members have the following bit
values:
@multitable @columnfractions .2 .2 .6
@item @code{SET} @strong{member} @tab @strong{Decimal value} @tab @strong{Binary value}