Database Reference
In-Depth Information
10
In the message box, click
No
to cancel the deletion. Two discontinued records cannot
be deleted because they have entries in the
Order Details
table. If this were a real
database, you would need to decide whether to set the
Discontinued
field of these
products to
No
(clear their check boxes) or to delete the entries from the
Order
Details
table before allowing the query to delete the product records.
Suppose you are concerned that someone might accidentally run this delete query
and destroy records you aren't ready to destroy. Let's change the query back to a
select query before saving it.
11
On the
Design
tool tab, in the
Query Type
group, click the
Select
button. Notice that
in the query design grid, the
Delete
row has disappeared and the
Sort
and
Show
rows are now displayed.
12
Save the query with the name
Delete Discontinued Products
.
TIP
If you want to delete obsolete records in the future, open the select query in
Design view, convert it to a delete query, and then run it.
CLEAN UP
Close the query, and then close the GardenCompany07 database.
7
Key points
▪
Create a query to display specific fields from specific records from one or more tables.
You can save the query for later use.
▪
You can use wizards or create queries manually in the Query Designer.
▪
Queries can use aggregate functions such as Sum and Avg to summarize data, and
they can perform calculations on matched data.
▪
An update query performs an updating action on its results, such as replacing the
contents of a field.
▪
A delete query deletes records that meet specific criteria. Use caution with this type
of query; the effects can be far reaching, and you can't recover deleted records.
