Visual Basic 6 Black Book:Working With Database Objects In Code
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RDO: Moving To The First Record In A Result Set
To move to the first record in an RDO result set, you can use the rdoResultset method MoveFirst. Let’s see an example. In this case, we’ll move to the first record in the result set named resultset that we’ve opened in our RDO code example, the rdocode project (see “A Full-Scale RDO Example” earlier in this chapter), when the user clicks the appropriate button:


Private Sub cmdFirst_Click()
On Error GoTo ErrLabel
resultset.MoveFirst
...
Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


After moving to the new record, we display the data in that record’s fields in the program’s text boxes, Text1 and Text2:


Private Sub cmdFirst_Click()
On Error GoTo ErrLabel

resultset.MoveFirst
Text1.Text = resultset("Name")
Text2.Text = resultset("Grade")

Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


RDO: Moving To The Last Record In A Result Set
To move to the last record in an RDO result set, you can use the rdoResultset method MoveLast. Let’s see an example. In this case, we’ll move to the last record in the result set named resultset that we’ve opened in our RDO code example, the rdocode project (see “A Full-Scale RDO Example” earlier in this chapter), when the user clicks the appropriate button:


Private Sub cmdLast_Click()
On Error GoTo ErrLabel

resultset.MoveLast
...
Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


After moving to the new record, we display the data in that record’s fields in the program’s text boxes, Text1 and Text2:


Private Sub cmdLast_Click()
On Error GoTo ErrLabel

resultset.MoveLast

Text1.Text = resultset("Name")
Text2.Text = resultset("Grade")

Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


RDO: Moving To The Next Record In A Result Set
To move to the next record in an RDO result set, you can use the rdoResultset method MoveNext. Let’s see an example. In this case, we’ll move to the next record in the result set named resultset that we’ve opened in our RDO code example, the rdocode project (see “A Full-Scale RDO Example” earlier in this chapter), when the user clicks the appropriate button. We check to make sure we’re not trying to move past the end of the record set with the EOF property, and if so, we make sure to move to the last record instead:


Private Sub cmdNext_Click()
On Error GoTo ErrLabel

If Not resultset.EOF Then resultset.MoveNext
If resultset.EOF And resultset.RowCount > 0 Then
resultset.MoveLast
End If
...
Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


After moving to the new record, we display the data in that record’s fields in the program’s text boxes, Text1 and Text2:


Private Sub cmdNext_Click()
On Error GoTo ErrLabel

If Not resultset.EOF Then resultset.MoveNext
If resultset.EOF And resultset.RowCount > 0 Then
resultset.MoveLast
End If

Text1.Text = resultset("Name")
Text2.Text = resultset("Grade")

Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


RDO: Moving To The Previous Record In A Result Set
To move to the previous record in an RDO result set, you can use the rdoResultset method MovePrevious. Let’s see an example. In this case, we’ll move to the previous record in the result set named resultset that we’ve opened in our RDO code example, the rdocode project (see “A Full-Scale RDO Example” earlier in this chapter), when the user clicks the appropriate button. We check to make sure we’re not trying to move past the beginning of the record set with the BOF property, and if so, we make sure to move to the first record instead:


Private Sub cmdPrevious_Click()
On Error GoTo ErrLabel

If Not resultset.BOF Then resultset.MovePrevious
If resultset.BOF And resultset.RowCount > 0 Then
resultset.MoveFirst
End If

Text1.Text = resultset("Name")
Text2.Text = resultset("Grade")

Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


After moving to the new record, we display the data in that record’s fields in the program’s text boxes, Text1 and Text2:


Private Sub cmdPrevious_Click()
On Error GoTo ErrLabel

If Not resultset.BOF Then resultset.MovePrevious
If resultset.BOF And resultset.RowCount > 0 Then
resultset.MoveFirst
End If

Text1.Text = resultset("Name")
Text2.Text = resultset("Grade")

Exit Sub

ErrLabel:
MsgBox Err.Description
End Sub


RDO: Executing SQL
You can execute SQL statements with RDO objects when you open a result set, as we saw in “RDO: Creating A Result Set” in this chapter. You can also execute an SQL statement with the rdoConnection object’s Execute statements like this:


SQLSel = "Select * from students"
rdoConnection.Execute SQLSel


A Full-Scale ADO Example
To illustrate ADO data handling in code, we’ll build an ADO project—the adocode project. This application lets you open the db.mdb file we built in the previous chapter using ADO objects to edit records, add records, and even delete records. You can also move through the database using the arrow buttons you see in Figure 25.5.


Figure 25.5  The adocode project at work.
To edit a record, just type the new value(s) into the text box(es) and click the Update button. To add a record, use the Add button, type the new value(s) into the text box(es), and click the Update button. That’s all there is to it—your changes will be reflected in the original database. For reference, the code for this example is located in the adocode folder on this book’s accompanying CD-ROM.




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