Visual Tools
The
vast majority of modern database packages use visual tools for manipulation
of data. Examples are packages such as Microsoft Access, Delphi and Visual
Foxpro. We will concentrate on one of these packages Microsoft Access in
this section.
Amending the data types and
field sizes
· Use File & Open and open up a
database.
· Click on a table in the list.
· Click on Design in the
toolbar.
· To change a field name, click
into the field name cell and alter the field name.
· To alter the data type, click
on the data type cell besides the relevant field name. Click on the drop
down list and select the new data type. Take care in altering data types
when data is already in the table, as this data can be affected or even
deleted by selecting an incompatible data type.
· Field Size or field properties
can be changed from the first row in the General tab below. Again if you are
reducing a field size, take care as data can be deleted.
· A field can be set as a
Primary Key from this screen as well. A Primary Key must be unique and
Access will enforce this if the user attempts to enter identical data into
the primary key field in more than one record. |
