MySQL does not have a boolean type. For yes/no or true/false information, I
usually use an enumerator (enum) and define the "false" value first and the
"true" second. (So "no" would be first and "yes" second.) Then, when I
query for the value in that field, I can ask for it minus one, and I get a
numerical value that can be translated more easily into a boolean value,
where "false" is 0 and "true" is 1. MySQL assigns the value of 1 to the
first element of the enumerator and reserves 0 for errors, so that's why you
have to subtract. If you simply query for the value of the field, you will
get "false," "true," "no," "yes," or whatever -- but, if you put any
arithmetic operator into your SQL statement, MySQL will send you the results
of calculation using the numerical internal representation instead.
create table boolean_table(boolean enum("false","true"));
insert into boolean_table values("true"));
<?php
$sql = "select boolean - 1 from boolean table";
$r = mysql_query($sql, $link) or die("Cannot get result");
$row = mysql_fetch_assoc($r);
if ($row["boolean"])
print "The value is true.\n";
?>
If I am working in C or PHP or another language that treats 0 as false and 1
as true, I can do this sort of test with the results -- or the reverse --
(this example is in C) --
if (!row[0])
puts("The value is false.");
Amittai Aviram
[EMAIL PROTECTED]
----- Original Message -----
From: "Angelo Carmo" <[EMAIL PROTECTED]>
aTo: <[EMAIL PROTECTED]>
Sent: Tuesday, October 29, 2002 8:36 PM
Subject: access2mysql data types
>
> Hi people,
>
> what is the best type to substitute the boolean type of msaccess tables.
> Or mysql databases support the boolean type?
>
> Angelo.
>
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