PHP and MySQL blobs

hey /prog/, I'm trying to update a mysql table, here is the column that is giving me issues:

document_content - mediumblob

How can I take a plain ol' string from PHP and update this column with a string? The column keeps updating to 0 and Google hasn't been much help.

>>14
$string  = "<enterpriseXMLtoSaveAsBlob>";
$string .= "omg hax}';DELETE FROM stupidTable;SELECT from stupidTable";
$string .= "</enterpriseXMLtoSaveAsBlob>";