PHP MySQL更新blob

Question

New to PHP/mySql and having trouble inserting and retrieving binary data. I have a mySql table called usr_pressdata. The field 'BinDat' is of type mediumblob.

$dat = $this->parseOverview($sql);
    // $dat is now a binary string

$datsql = "Update usr_pressdata Set BinDat = " . $dat;
$datresult = mysql_query($datsql, $this -> conn) or die(mysql_error());

$getdat = "Select * from usr_pressdata";
$getdatresult = mysql_query($getdat, $this -> conn) or die(mysql_error());
$row = mysql_fetch_array( $getdatresult );
   $retval = $row['BinDat'];

In this example my goal is that $retval == $dat but it does not. I suspect that my query string $datsql is incorrect. Can someone correct this example code? Thank you.

Answer 1

When inserting values in a table (or more generally, when including a value in an SQL request):

1. the string must be enclosed between quotes ('...')
2. the string must be “escaped” using mysql_real_escape_string so as to prevent SQL injection .

So you need to write something like:

$request = "UPDATE usr_pressdata SET bindat= '" . mysql_real_escape_string($dat) . "';";

I suspect you may want to add a WHERE someColumn = someCondition clause at the end, because as it is now, it would affect all the rows in the table.