Data object's navigation methods

Select

Opens a database connection and selects a record set using using the scope defined by the scope object and sorted according to the sort object.  This method should be called before calls are made to any navigation methods and most of the data access methods. The current position is set to the top record if the method succeeds and there are records in the resulting record set.

Function Select( param (optional ) )

Parameters:

string param - set param to "append" to request fast record insertion, append only can be done in this mode(write only record set).

Return value:

boolean - true: the record set was opened successfully and there are records in the record set; false: the record set was opened successfully, but the record set is empty.

An exception is thrown in case of errors.

VB Sample

' Sample 1

Dim val

If DB.Select() Then

   Do

      val = DB.GetCellVaue( "Field1" )

   Loop While( DB.GoNext() )

End If

' Sample 2

DB.Select( "append" )

For I = 1 To 1000

   DB.AppendStart()

   DB.SetCellVaue "Field1", I

   DB.AppendFinish()

Next 

GoTop

Moves the current record position to the first record. Select must be called before this method is used.

Function GoTop()

Parameters:

none

Return value:

boolean - true: operation succeeded; false: no records in the record set.

An exception is thrown in case of errors.

VB Sample

Dim first_val, last_val

If DB.Select() Then

   DB.GoBottom()

   last_val = DB.GetCellVaue( "Field1" )

   DB.GoTop()

   first_val = DB.GetCellVaue( "Field1" )

End If 

GoNext

Moves the current record position to the next record. Returns false if there is no record to move to. Select must be called before this method is used. 

Function GoNext()

Parameters:

none

Return value:

boolean - true: operation succeeded; false: no records in the record set or the current position is the last record.

An exception is thrown in case of errors.

VB Sample Dim val

If DB.Select() Then

   Do

      val = DB.GetCellVaue( "Field1" )

   Loop While( DB.GoNext() )

End If  

GoPrevious

Moves the current record position to the previous record. Returns false if there is no record to move to. Select must be called before this method is used.

Function GoPrevious()

Parameters:

none

Return value:

boolean - true: operation succeeded; false: no records in the record set or the current position is at the first record.

An exception is thrown in case of errors.

VB Sample

Dim val

If DB.Select() Then

   DB.GoBottom()

   Do

      val = DB.GetCellVaue( "Field1" )

   Loop While( DB.GoPrevious() )

End If   

GoBottom

Moves the current record position to the last record in the record set. Select must be called before this method is used.

Function GoBottom()

Parameters:

none

Return value:

boolean - true: operation succeeded; false: no records in the record set.

An exception is thrown in case of errors.

VB Sample

Dim first_val, last_val

If DB.Select() Then

   DB.GoBottom()

   last_val = DB.GetCellVaue( "Field1" )

   DB.GoTop()

   first_val = DB.GetCellVaue( "Field1" )

End If 

GoRandom

Moves the current record position to the record identified by the record number that is passed to GoRandom as a parameter. Returns false if the record number parameter is less than 0 or greater than GetRecordCount - 1. Select should be called prior to this method.

Function GoBottom( rec_num )

Parameters:

integer rec_num - a zero-based record position to set the current record position to; range: from 0 to GetRecordCount - 1

Return value:

boolean - true: operation succeeded; false: no records in the record set.

An exception is thrown in case of errors.

VB Sample

If DB.Select() Then

   For I = 0 To 999

      DB.GoRandom( I )

      DB.GetCellVaue( "Field1" )

   Next 

End If