Databases Reference
In-Depth Information
If
$cfg['ShowBlob']
is set to
TRUE
, we see the following in the
BLOB
field:
To really
see
the image from within phpMyAdmin, refer to Chapter 16,
MIME-Based Transformations
.
The
$cfg['ProtectBinary']
parameter controls what can be done while editing
binary fields (
BLOB
s and any other field with the
binary
attribute). The default
value
'blob'
protects against the editing of
BLOB
fields but allows us to edit other
fields marked as
binary
by MySQL. A value of
'all'
would protect against editing
even
binary
fields. A value of
FALSE
would protect nothing, thus allowing us to edit
all fields. If we try the last choice, we see the following in the
Edit
panel for this row:
Chances are this is not our favorite image editor! In fact, data corruption may result
even if we save this row without touching the
BLOB
field. But the setting to remove
ProtectBinary
exists because some users put text in their
BLOB
fields and they
need to be able to modify this text.
MySQL
BLOB
data types are actually similar to their corresponding
TEXT
data
types, but we should keep in mind that a
BLOB
has no character set, whereas a
TEXT
column has a character set that impacts sorting and comparison. This is why
phpMyAdmin can be configured to allow editing of
BLOB
fields.
ENUM and SET
Both these field types are intended to represent a list of possible values; the difference
is that the user can choose only one value from a defined list of values with
ENUM
,
and more than one value with
SET
. With
SET
, the multiple values all go into one cell;
multiple values do not imply the creation of more than one row of data.
Search WWH ::
Custom Search