sqlite_udf_decode_binary
(PHP 5)
sqlite_udf_decode_binary -- Decode binary data passed as parameters to an UDF
说明
string
sqlite_udf_decode_binary ( string data )
sqlite_udf_decode_binary() decodes the binary encoding
that was applied to the parameter by either
sqlite_udf_encode_binary() or
sqlite_escape_string().
You must call this function on parameters passed to your UDF if you need
them to handle binary data, as the binary encoding employed by PHP will
obscure the content and of the parameter in its natural, non-coded form.
PHP does not perform this encode/decode operation automatically as it would
severely impact performance if it did.
例
例子 1. binary-safe max_length aggregation function example
<?php
$data = array(
'one',
'two',
'three',
'four',
'five',
'six',
'seven',
'eight',
'nine',
'ten',
);
$db = sqlite_open(':memory:');
sqlite_query($db, "CREATE TABLE strings(a)");
foreach ($data as $str) {
$str = sqlite_escape_string($str);
sqlite_query($db, "INSERT INTO strings VALUES ('$str')");
}
function max_len_step(&$context, $string)
{
$string = sqlite_udf_decode_binary($string);
if (strlen($string) > $context) {
$context = strlen($string);
}
}
function max_len_finalize(&$context)
{
return $context;
}
sqlite_create_aggregate($db, 'max_len', 'max_len_step', 'max_len_finalize');
var_dump(sqlite_array_query($db, 'SELECT max_len(a) from strings'));
?>
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