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sqlite_udf_decode_binary

(no version information, might be only in CVS)

sqlite_udf_decode_binary -- Decode binary data passed as parameters to an UDF.

Description

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'));

?>

See also sqlite_udf_encode_binary(), sqlite_create_function() and sqlite_create_aggregate().



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