1. DEALING WITH MORE THAN ONE TABLE
RELATIONAL DATABASE

2. 1. Setting up Objects
Dim objConnection As New OleDb.OleDbConnection( _
Set up the objects
"Provider=Microsoft.Ace.OLEDB.12.0;Data Source
=C:DataBase.accdb")
Dim objTableDA As New _
OleDb.OleDbDataAdapter("Select * from Table", _
objConnection)
Dim objTableCB As New _
OleDb.OleDbCommandBuilder(objTableDA)
Dim objDataSet As New DataSet()

3. 2. Filling the DataSet
objDataSet.Clear()
objTableDA.FillSchema(objDataSet, _
SchemaType.Source, “Table")
objTableDA.Fill(objDataSet, “Table")

4. 3. Displaying Data on Form
Dim objRow As DataRow
objRow = _ objDataSet.Tables(“Table").Rows.Find _
(Insert Code for Primary Key Here)
lblField1Text = objRow.Item(“Field1")
txtField2.Text = objRow.Item(“Field2")
txtField3.Text = objRow.Item(“Field3")
End Sub

5. Column 0
Row 0
Row 1
Row 2
Row 3

6. 4.Storing Details
Public Sub StoreDetails()
Dim objRow As DataRow
objRow = _
objDataSet.Tables(“Table").Rows.Find(PrimaryKey)
objRow.Item(“Field1") = txtField1.Text
objRow.Item(“Field2") = txtField2.Text
End Sub

7. 5. Update Changes to DataSet
 In the previous slide we updated our
database but…
objTableDA.Update(objDataSet, “Table”)

8. 6.Add a New Row to DataSet
Dim objRow As DataRow
objRow = objDataSet.Tables(“Table”).NewRow
objRow.Item(“Field1”) = InputBox(“Field1?”)
objRow.Item(“Field2”) = InputBox(“Field2?”)
objRow.Item(“Field3”) = InputBox(“Field3?”)
objDataSet.Tables(“Table”).Rows.Add(objRow)
objTableDA.Update(objDataSet, “Table”)

9. 7. Deleting a Row
Dim objRow As DataRow
objRow =
objDataSet.Tables(“Tables").Rows.Find(PrimaryKey)
objRow.Delete()
objTableDA.Update(objDataSet, “Table")
Retrieve()

11. 1.Setting up Objects
Dim objConnection As New OleDb.OleDbConnection( _
"Provider=Microsoft.ACE.OLEDB.12.0;Data Source _
=surgery.accdb")
Dim objOwnerDA As New
OleDb.OleDbDataAdapter("Select * from Owners", _
objConnection)
Dim objOwnerCB As New
OleDb.OleDbCommandBuilder(objOwnerDA)
Dim objDS As New DataSet()

12. 2.Fill the Data Set
objDS.Clear()
objOwnerDA.FillSchema(objDS, _
SchemaType.Source, "Owners")
objOwnerDA.Fill(objDataSet, "Owners")

13. Row 0
Row 1
Row 2
Row 3

14. Row 0
Row 1
Row 2
Row 3
„objDS.Tables("Owners").Rows.Count = 4
„For i = 0 to 4 would cause a problem
„There is no row 4!

15. 3.Populate ComboBox
cboOwners.Items.Clear()
Dim i As Integer, strCurrentID As String
For i = 0 To objDS.Tables("Owners").Rows.Count - 1
strCurrentID = _
objDS.Tables("Owners").Rows(i).Item("OwnerID")
cboOwners.Items.Add(strCurrentID)
Next
cboOwners.SelectedIndex = 0

16. 4.Display a Record
Public Sub FillOwnersDetails()
Dim objRow As DataRow
objRow = _
objDS.Tables("Owners").Rows.Find _
(cboOwners.SelectedItem.ToString)
lblOwnerID.Text = _
objRow.Item("OwnerID")
txtName.Text = objRow.Item("Name")
txtAddress.Text =
objRow.Item("Address")
End Sub

17. 5.Storing Details
Public Sub StoreOwnerDetails()
Dim objRow As DataRow
If lblOwnerID.Text = "" Then Exit Sub
objRow = _
objDS.Tables("Owners").Rows.Find _
(lblOwnerID.Text)
objRow.Item("Name") = txtName.Text
objRow.Item("Address") = _
txtAddress.Text
End Sub

18. 6.ImplementProcedures
 Call the Fill Owner Details behind the Combo Box

19. 7.Persisting Changes
 Code to be placed behind the save button
 If the user has made changes to a field we want
to store the changes to the dataset and then
persist those changes to the DB
1. Call the StoreOwnerDetails()
2. objOwnerDA.Update(objDS, “Owners”)

20. 8.Add Row to our DataSet
Dim objRow As DataRow
objRow = objDS.Tables(“Owners”).NewRow
objRow.Item(“OwnerID”) = InputBox(“Owner ID?”)
objRow.Item(“Name”) = InputBox(“Name?”)
objRow.Item(“Address”) = InputBox(“Address?”)
objDS.Tables(“Owners”).Rows.Add(objRow)
StoreOwnerDetails()
objOwnerDA.Update(objDS, “Owners”)
 Remember to loop through records again !

21. 9.Deleting a Row
Dim objRow As DataRow
objRow = _
objDS.Tables("Owners")._
Rows.Find(cboOwners.SelectedItem.ToString)
objRow.Delete()
objOwnerDA.Update(objDS, "Owners")
Retrieve()

22. 10.Creating Relationships
 We have created two tables owners and pets.
 What if we want to use both tables on our
form?
 Pull data from both tables into our dataset
 Then set up an OwnerID relationship between
the two.

24. 11.Set up more Objects
Dim objPetDA as New _
OleDbDataAdapter(“Select * from Pets”,_
, objConnection)
Dim objPetCB As New _
OleDbCommandBuilder(objPetDA)

25. lstPets

26. Filling in Pet Details
 Add the following code to your Retrieve button code or
Retrieve Method
 It should go in after you have filled the dataset with
Owners data
objPetDA.FillSchema(objDataSet, _
SchemaType.Source, "Pets")
objPetDA.Fill(objDS, "Pets")
'Setup our Relationship
objDS.Relations.Clear()
objDS.Relations.Add("Owners2Pets", _
objDS.Tables("Owners").Columns("OwnerID"), _
objDS.Tables("Pets").Columns("OwnerID"))

27. FillPetDetails()
Public Sub FillPetDetails()
Dim objOwner As DataRow, objPet As _
DataRow
Dim strPetEntry As String
lstPets.Items.Clear()
objOwner = objDS.Tables(“Owners”)._
Rows.Find(cboOwners.SelectedItem.ToString)

28. Loop through records
For Each objPet in
objOwner.GetChildRows(“Owners2Pets”)
strPetEntry = objItem(“PetID”) & “, “ ” & _
objPet.Item(“PetName”) & “, “ &
objPet.Item(“Type”)
lstPets.Items.Add(strPetEntry)
Next
End Sub

29. Finishing Touches
 To end of your retrieve records code add the
following line:
FillPetDetails()
 Add the following code to the
SelectedIndexChanged event of our combo
box:
FillPetDetails()