Deleting Records in a Back-end Database

Description

To delete records into a back-end database, you use the SQL DELETE command. The general syntax of the DELETE command is:

DELETE FROM tablename WHERE Column_Expression = Value

Before proceeding, start Access, open Alphasports.mdb, copy the customer table, and name the copy customer_copy.

Let us delete a record from the Customer_Copy table. First, we will query the table and prove that it contains a specific record. In the Interactive window create the variables we will need.

dim conn as SQL::Connection
dim query_cmd as C
dim delete_cmd as C

Open the connection.

? conn.open("{A5API=Access,FileName='C:\Program Files\A5V8\MDBFiles\Alphasports.mdb',UserName='Admin'}")
= .T.

Find the records where the firstname field begins with "Y". This requires the use of a Portable SQL function named SubString(). First, we must enable Portable SQL by setting the conn.PortableSQLEnabled property to TRUE.

conn.PortableSQLEnabled = .t.
query_cmd = "select * from customer_copy where substring(firstname,1,1) = 'Y'"

Now, retrieve and preview the data.

? conn.execute(query_cmd)
= .T.
sql_resultset_preview(conn.ResultSet)

Now delete the record.

delete_cmd = "DELETE FROM Customer WHERE substring(firstname,1,1) = 'Y'"
? conn.execute(delete_cmd)
= .T.

Now, look at the results.

conn.execute(query_cmd)
SQL_ResultSet_Preview(conn.resultset)

There are no records that match this filter.

conn.close()

Limitations

Desktop Applications Only