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Posted by Andy Hassall on 11/14/09 11:26
On 10 Sep 2005 10:36:06 -0700, "sime" <get_simon_hobbs@hotmail.com> wrote:
>I have a blob field in a mysql database table. I want to copy a blob
>from one record to another. I am having trouble transferring the data
>via a php variable. Maybe I need to addslashes or convert to Hex or
>something. I've tried a few things but can't quite get it. Here is
>simplified code.
>
> mysql_select_db($dbname, $connection);
You've said you are "having trouble", yet you have not described what
"trouble" you're having, you've only posted some code.
> mysql_query ($query, $connection);
>
>I would love any advice I can get.
MySQL and PHP can give you advice for starters; make sure error_reporting is
set to E_ALL, and check the result code of every mysql_* call; if it returns
false, use mysql_error() to print a full error message.
> $query = "UPDATE mytable
> SET blobthing = ".$varblobthing.",
> WHERE id = 2;";
You're missing quotes around the value, escaping using mysql_escape_string,
and what's that comma at the end of the second line for?
Or, an alternative approach:
(http://dev.mysql.com/doc/mysql/en/example-user-variables.html)
mysql> create table t (id int, b blob);
Query OK, 0 rows affected (0.09 sec)
mysql> insert into t values (1, 'one');
Query OK, 1 row affected (0.06 sec)
mysql> select * from t;
+------+------+
| id | b |
+------+------+
| 1 | one |
| 2 | two |
+------+------+
2 rows in set (0.00 sec)
mysql> insert into t values (2, 'two');
Query OK, 1 row affected (0.00 sec)
mysql> select @b:=b from t where id=1;
+-------+
| @b:=b |
+-------+
| one |
+-------+
1 row in set (0.08 sec)
mysql> update t set b=@b where id=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from t;
+------+------+
| id | b |
+------+------+
| 1 | one |
| 2 | one |
+------+------+
2 rows in set (0.00 sec)
--
Andy Hassall :: andy@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool
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