User`s guide

Replacing Existing Database Data with Exported Data
6-21
Replacing Existing Database Data with Exported Data
This example updates the Month field that you previously imported (“Exporting
Data to New Record in Database” on page 6-18) into the yearlySales table of the
dbtoolboxdemo data source using the following Database Toolbox functions:
• close
• update
For details about these functions, see matlab\toolbox\database\dbdemos
\dbupdatedemo.m.
1
Change the month in yearlySales table from March to March2010. Assign the
new month value to the newdata cell array.
colnames = {'Month'};
newdata = {'March2010'}
newdata =
'March2010'
2
Specify the record to update in the database by defining an SQL WHERE statement
and assigning it to the variable whereclause. The record to update is the record
whose Month is March. Because the date string is within a string, it is embedded
within two single quotation marks rather than one.
whereclause = 'where Month = ''March'''
whereclause =
where Month = 'March'
3
Export the data, replacing the record whose Month is March.
update(conn,'yearlySales',colnames,newdata,whereclause)
4
In Microsoft Access, view the yearlySales table to verify the results.
5
Disconnect from the database.
close(conn);