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Manage() provides data management functionality for your application and/or process.
Below is the code for Manage():
'
' Manage()
'
' This function performs record adds and updates using locking
'
Sub Manage()
Console.WriteLine("MANAGE")
' populate the table with data
Add_CustomerMaster_Records()
' display contents of table
Display_Records()
' update a record under locking control
Update_CustomerMaster_Record()
' display again after update and effects of lock
Display_Records()
End Sub
'
' Add_CustomerMaster_Records()
'
' This function adds records to table CustomerMaster from an
' array of strings
'
Public Structure CUSTOMER_DATA
' struct members
Public number, zipcode, state, rating, name, address, city As String
' struct constructor
Public Sub New(ByVal number As String, ByVal zipcode As String, ByVal state As String, ByVal rating As String, ByVal name As String, ByVal address As String, ByVal city As String)
Me.number = number
Me.zipcode = zipcode
Me.state = state
Me.rating = rating
Me.name = name
Me.address = address
Me.city = city
End Sub
End Structure
Sub Add_CustomerMaster_Records()
Dim data(3) As CUSTOMER_DATA
data(0) = New CUSTOMER_DATA("1000", "92867", "CA", "1", "Bryan Williams", "2999 Regency", "Orange")
data(1) = New CUSTOMER_DATA("1001", "61434", "CT", "1", "Michael Jordan", "13 Main", "Harford")
data(2) = New CUSTOMER_DATA("1002", "73677", "GA", "1", "Joshua Brown", "4356 Cambridge", "Atlanta")
data(3) = New CUSTOMER_DATA("1003", "10034", "MO", "1", "Keyon Dooling", "19771 Park Avenue", "Columbia")
Dim nRecords As Integer = data.Length
Delete_Records(MyRecord)
Console.WriteLine(ControlChars.Tab + "Add records...")
Try
Dim i As Integer
For i = 0 To nRecords - 1
MyRecord.Clear()
' populate record buffer with data
MyRecord.SetFieldAsString(0, data(i).number)
MyRecord.SetFieldAsString(1, data(i).zipcode)
MyRecord.SetFieldAsString(2, data(i).state)
MyRecord.SetFieldAsString(3, data(i).rating)
MyRecord.SetFieldAsString(4, data(i).name)
MyRecord.SetFieldAsString(5, data(i).address)
MyRecord.SetFieldAsString(6, data(i).city)
' add record
MyRecord.Write()
Next
Catch E As CTException
Handle_Exception(E)
End Try
End Sub
'
' Delete_Records()
'
' This function deletes all the records in the table
'
Sub Delete_Records(ByVal record As CTRecord)
Dim found As Boolean
Console.WriteLine(ControlChars.Tab + "Delete records...")
Try
' enable session-wide lock flag
MySession.Lock(LOCK_MODE.WRITE_BLOCK_LOCK)
' read first record
found = record.First()
While (found) ' while records are found
' delete record
record.Delete()
' read next record
found = record.Next()
End While
' reset session-wide locks
MySession.Unlock()
Catch E As CTException
Handle_Exception(E)
End Try
End Sub
'
' Display_Records()
'
' This function displays the contents of a table. First() and Next()
' fetch the record. Then each field is parsed and displayed
'
Sub Display_Records()
Dim found As Boolean
Dim custnumb As String
Dim custname As String
Console.Write(ControlChars.Tab + "Display records...")
Try
' read first record
found = MyRecord.First()
While (found)
custnumb = MyRecord.GetFieldAsString(0)
custname = MyRecord.GetFieldAsString(4)
Console.WriteLine(ControlChars.NewLine + ControlChars.Tab + ControlChars.Tab + "{0,-8}{1,-20}", custnumb, custname)
' read next record
found = MyRecord.Next()
End While
Catch E As CTException
Handle_Exception(E)
End Try
End Sub
'
' Update_CustomerMaster_Records()
'
' Update one record under locking control to demonstrate the effects
' of locking
'
Sub Update_CustomerMaster_Record()
Console.WriteLine(ControlChars.Tab + "Update Record...")
Try
' enable session-wide lock flag
MySession.Lock(LOCK_MODE.WRITE_BLOCK_LOCK)
MyRecord.Clear()
MyRecord.SetFieldAsString(0, "1003")
' find record by customer number
If (MyRecord.Find(FIND_MODE.EQ)) Then
MyRecord.SetFieldAsString(4, "KEYON DOOLING")
' rewrite record
MyRecord.Write()
Console.WriteLine(ControlChars.Tab + "Press <ENTER> key to unlock")
Console.ReadLine()
End If
' reset session-wide locks
MySession.Unlock()
Catch E As CTException
Handle_Exception(E)
End Try
End Sub
