|
What Is A Subform?
A subform is a form that is placed in a parent form, called the
main form. Subforms are particularly useful to display data from
tables and queries that have one-to-many relationships. For example,
in the sample below, data on the main form is drawn from an item
information table while the subform contains all of the orders for
that item. The item record is the "one" part of this one-to-many
relationship while the orders are the "many" side of the relationship
since many orders can be placed for the one item.
![[Sample Subform]](Sumform_files/samplesubform.gif)
The remainder of this page explains three methods for creating
subforms and they
assume that the data tables and/or queries have already been created.
Create a Form and Subform at Once
Use this method if neither form has already been created. A main
form and subform
can be created automatically using the form wizard if table
relationships are set
properly or if a query involving multiple tables is selected.
For example, a relationship
can be set between a table containing customer information and
one listing customer orders so the orders for each customer are
displayed together using a main form and subform. Follow these
steps to create a subform within a form:
- Double-click Create form by using wizard on the database
window.
- From the Tables/Queries drop-down menu, select the
first table or query from which the main form will display its
data. Select the fields that should appear
on the form by highlighting the field names in the Available
Fields list on the
left and clicking the single arrow > button or click
the double arrows >> to
choose all of the fields.
- From the same window, select another table or query from the
Tables/Queries
drop-down menu and choose the fields that should appear on the
form.
Click Next to continue after all fields have been selected.
- Choose an arrangement for the forms by selecting form with
subform(s) if the
forms should appear on the same page or Linked forms
if there are many
controls on the main form and a subform will not fit. Click
Next to proceed to
the next page of options.
- Select a tabular or datasheet layout for the form and click
Next.
- Select a style for the form and click Next.
- Enter the names for the main form and subform. Click Finish
to create the
forms.
- New records can be added to both tables or queries at once
by using the new combination form.
Subform Wizard
If the main form or both forms already exist, the Subform Wizard
can be used to
combine the forms. Follow these steps to use the Subform Wizard:
- Open the main form in Design View and make sure the
Control Wizard button
on the
toolbox is pressed in.
- Click the Subform/Subreport icon
on the toolbox and draw the outline of
the subform on the main form. The Subform Wizard dialog box
will appear when the mouse button is released.
- If the subform has not been created yet, select "Use existing
Tables and Queries". Otherwise, select the existing form that
will become the subform.
Click Next to continue.
- The next dialog window will display table relationships assumed
by Access. Select one of these relationships or define your
own and click Next.
- On the final dialog box, enter the name of the subform and
click Finish.
Drag-and-Drop Method
Use this method to create subforms from two forms that already
exist. Make sure
that the table relationships have already been set before proceeding
with these steps.
- Open the main form in Design View and select Window|Tile
Vertically to display both the database window and the form
side-by-side.
- Drag the form icon beside the name of the subform onto the
detail section of the
main form design.
|