First Steps - Mastering phpMyAdmin 2.8 for Effective MySQL Management - page 58

The VARCHAR type is widely used when the field content is alphanumeric, because
the contents will occupy only the space needed for it. This type requires a maximum
length, which we specify. If we forget to do so, a small pop-up message reminds us
later when we save. For the page count and the author identification, we have chosen
INT type (integer), as depicted in the following screenshot:
There are other attributes for fields, but we will leave them empty in this short
example. You might notice the Add 1 Field(s) dialog at the bottom of the screen. We
can use it to add some fields to this table creation panel by entering the appropriate
value and hitting Go . The number of rows would change according to the new
number of fields, leaving intact the information already entered about the first four
Fields. Before saving the page, let's define some keys.
Choosing Keys
A table should normally have a primary key (a field with unique content that
represents each row). Having a primary key is recommended for row identification,
better performance, and possible cross-table relations. A good value here is the ISBN;
so we select Primary for the isbn field. As $cfg['PropertiesIconic'] is set to TRUE
by default, we see icons indicating the various index possibilities. Moving the mouse
over them or over the radio buttons reveals Primary , Index , Unique , and Full text .
Index management (also referred to as Key management)
can be done at initial table creation, or later in the Structure
sub-page of Table view.