1. ADO Recordsets

2. Recordset Objects Similar to Tables and Queries: data Using VBA/VBScript you… –Open a recordset, –Locate a record –Update or add a record –Close

3. Controls on Forms I: Recordsets The usual job of forms: showing data from tables/queries With recordsets, you must use VBA/VBScript to show data in controls You fill listboxes, textboxes, etc The form doesn't fill them for you This is not "bound forms"

4. Controls on Forms II: Recordsets Another job of forms: taking data from controls into tables/queries With recordsets, you must use VBA/VBScript to take form data from the controls and save it The listboxes, textboxes, etc are the source of tabled data But, the form doesn't update the table for you This is not "bound forms"

5. Bound forms vs. Recordsets Use standard forms for input and output Use recordset programming to… –Read data from tables/queries –Fill controls on forms with this data –Read data in controls on forms –Update the tables/queries with user changes to the form data But, do not use recordset programming instead of binding forms to tables/queries. Use it to augment forms.

6. Opening with Recordset Cursors The cursor element controls: record navigation updatability of data visibility of changes by other users speed of application

7. Types of Cursors Static Dynamic KeySet ForwardOnly

8. Static Cursor A static copy of a set of records that you can use to find data or generate reports Additions, changes, or deletions by other users are not visible Bookmarks are supported MovePrevious is available RecordCount property is available Supports batch updates (SQL Server)

9. Opening Static Tables ' our textbook opens static-cursor recordsets like this Dim cnn As adodb.Connection Dim rst As New adodb.Recordset Set cnn = CurrentProject.Connection rst.Open "tblPeople",cnn, adOpenStatic ' … records are processed as needed ' and then the table is closed safely rst.Close Set rst = Nothing

10. Dynamic Cursor Additions, changes, and deletions by other users are visible all types of movement through the recordset are allowed Not a fast cursor MovePrevious is available Bookmarks not supported RecordCount property is not available Does not support batch updates

11. Opening Dynamic Tables ' our textbook opens table-recordsets like this Dim cnn As adodb.Connection Dim rst As New adodb.Recordset Set cnn = CurrentProject.Connection rst.Open "tblPeople",cnn,adOpenDynamic,, adCmdTable ' … records are processed as needed ' and then the table is closed safely rst.Close Set rst = Nothing

12. Opening Dynamic SQL ' SQL recordsets can restrict and order the records as follows Dim strSQL As String strSQL = "SELECT * From tblEmployee " & _ "WHERE HireDate < #01/01/90# " & _ "ORDER BY HireDate" Dim cnn As adodb.Connection Dim rst As New adodb.Recordset Set cnn = CurrentProject.Connection rst.Open strSQL, cnn, adOpenDynamic,,adCmdText ' … process as needed … rst.Close Set rst = Nothing

13. KeySet Cursor Like a dynamic cursor, but faster Bookmarks are supported, unlike dynamic Data changes by other users are visible Deleted recs by other users are inaccessible Can't see records that other users add: –Until you refresh the cursor with rst.Resync Supports batch updates (SQL Server)

14. Static/Dynamic/Keyset Cursor Recordsets (finding numbers) Locate records, not just one record Should open with SQL for speedier finds rst.MoveFirst Rst.Find "pkPeopleID=" & cboNavigation If rst.EOF or rst.BOF = True then MsgBox "Failed to find " Endif

15. Static/Dynamic/Keyset Cursor Recordsets (finding dates) Locate records, not just one record Should open with SQL for speedier finds dteHire=#01/03/01# strFind="HireDate=" & "#" & dteHire & "#" rst.MoveLast rst.Find strFind,, adSearchBackward If rst.BOF = True then MsgBox "Failed to find " Endif

16. Static/Dynamic/Keyset Cursor Recordsets (finding strings) Locate records, not just one record Should open with SQL for speedier finds strName="Poynor" strCriteria="LastName=" & "'" & strName & "'" rst.MoveFirst rst.Find strCriteria,, adSearchForward If rst.EOF = True then MsgBox "Failed to find " Endif

17. Static/Dynamic/Keyset Cursor Recordsets (seeking strings) rst.Index = "LastNameIndex" ' this index MUST be hard coded in the table!! rst.Open "tblPeople", cnn, adOpenStatic, adLockOptimistic, adCmdTableDirect strWhich = "first: " ' strWhich is used below strName = InputBox("Enter a last name") rst.Seek strName, adSeekFirstEQ Do Until strName <> rst!LastName ' loop works bc rst is ordered by last name Debug.Print "Sought " & strWhich & rst!FirstName & " " & rst!LastName rst.MoveNext strWhich = "next: " Loop Locate records fast based on a table index

18. ForwardOnly Cursor This is the default Cursor You only scroll forward through records Improves performance when you make only one pass through a recordset Bookmarks not supported Update, AddNew are not available MovePrevious, Find are not available RecordCount property is not available Does not support batch updates

19. Moving in Recordset (BOF) rst.MovePrevious If rst.BOF = True Then…. ' true if you tried to go before the first record rst.MoveNext If rst.EOF = True Then…. ' true if you tried to go after the last record Moving in Recordset (EOF)

20. ' here is how to store a recordset into an array Dim varArray() as Variant rst.MoveFirst varArray = rst.GetRows rst.Close ' how many records and fields were stored? (Chap. 8) intRecordCount = UBound(varArray, 2) + 1 intFieldCount = UBound(varArray, 1) + 1 'stored as varArray(Fields, Records) Arrays created from Recordsets

21. rst!FirstName = "Carrie" rst(1) = "Carrie" rst("FirstName") = "Carrie" rst.Fields.Item(1).Value = "Carrie" rst!LastName = "Ohn" Recordsets Syntax for Fields

22. rst.Open "tblPeople", CurrentProject.Connection, adOpenStatic, adLockOptimistic ' necessary to write rst.Find "pkPeopleID=" & 8 If not rst.EOF then rst!Salary = 62000 rst.Update 'save changes rst.CancelUpdate 'OR cancel the update Editing Recordsets

23. rst.Open "tblPeople", CurrentProject.Connection, adOpenStatic, adLockOptimistic ' necessary to write rst.AddNew ' add a blank record ' optional to add values to fields rst!Salary = 52000 rst!Sex = "F" rst!FirstName="Sammin" rst!MiddleName="Janet" rst!LastName="Evening" rst.Update 'save changes rst.CancelUpdate 'OR cancel the new record Adding to Recordsets (two-step process)

24. rst.Delete ' that's all folks Deleting from Recordsets

25. Dim varBookmark As Variant varBookmark = rst.Bookmark ' remember position rst.MoveFirst ' start at first position Do While Not rst.EOF ' calculate something you need rst.MoveNext ' move to next position Loop rst.Bookmark = varBookmark ' restore position ' this will throw an error for dynamic and forward cursors. To prevent the error message (but live with no bookmarks) use this logic: If rs.Supports(adBookmark) Then… Keeping track of record position in recordsets