Changing Table Structures - Mastering phpMyAdmin 3.1 for Effective MySQL Management - page 99

First, we add a BLOB field and cover_photo to our book table. If we now browse the
table, we can see the field length information, [BLOB - 0 B] , for each BLOB field.
This is because the Show BLOB display option (do you remember the Options
slider?) has no check mark by default. So, it blocks the display of BLOB contents in
Browse mode. This behavior is intentional. Usually, we cannot do anything with
binary data represented in plain text.
Binary content uploads
If we edit one row, we see the Binary - do not edit warning and a Browse… button.
The exact caption on this button depends on the browser. Even though editing is not
allowed, we can easily upload a text or binary file's contents into this BLOB column.
Let's choose an image file using the Browse button—for example, the logo_left.
png file in a test copy of the phpMyAdmin/themes/original/img directory located
on our client workstation. We now click Go .
We need to keep in mind some limits for the upload size. Firstly, the BLOB field size
is limited to 64K. Hence, phpMyAdmin reminds us of this limit with the Max: 65,536
Bytes warning. Also, there could be limits inherent to PHP itself (see Chapter 8 for
more details). We have now uploaded an image inside this field for a specific row.