Microsoft Office Tutorials and References
In Depth Information
Section 7: Modifying data using queries
7
Modifying data
using queries
In this section:
The queries described in this section are a special type called action
que■ Creating a table by using a Make
Table query
Adding data to an existing table with
an Append query
Changing data in an existing table
with an Update query
Deleting data in tables with a Delete
query
Adding only new data that is not
already in a table
Updating a column based on an
expression
Resetting an AutoNumber with an
Append query
ries, which differ from the select queries previously discussed in that
they are used to change data in the database. For example, rather than
doing a search and replace, you can create a query to do that work for
you. However, the power of these queries is greater than a simple search
and replace because action queries can be based on data that you have in
other tables in your database.
An example of a great use for action queries is when, after importing data
from other systems into Access, you need to reorganize the data into
existing or new tables. A Make Table query would enable you to create
and add data to a new table and can be used to create new lookup lists of
choices, or improve a design by splitting data into several new tables.
If you have a complex set of processing steps, then a Delete query could
be used to empty tables, and then an Append query to repopulate the
data, or an Update query used to modify data.
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