SQL transaction statement in vb.net - sql

Question

I'm making a project that is linked to Microsoft SQLServer, used to enter, remove, edit data about customers and orders. The full system works, however I've been advised to use transactions rather than regular SQL statements to add/remove/edit data etc.
The trouble is, I've not used these before and from my research over the last few hours, I can't work out how to even begin them.
Can anybody advise me how to turn the following code into a transaction?
Public Shared Function SaveNewPerson(ByVal firstName As String, lastName As String, ByVal age As Integer, ByVal postcode As String, m_cn As OleDbConnection)
Dim Dc As New OleDbCommand
Dc.Connection = m_cn
m_cn.Open()
Dc.CommandText = "INSERT INTO tblPerson([firstName], [lastName], [age], [postcode]) VALUES('" & firstName & "', '" & lastName & "', '" & age & "', '" & postcode & "')"
Dc.ExecuteNonQuery()
Dim personID As Integer
Dc.CommandText = "SELECT ##IDENTITY"
Dc.CommandType = CommandType.Text
personID = CType(Dc.ExecuteScalar(), Integer)
m_cn.Close()
End Function

Answer 1

I've just been learning TSQL, see if this sort of code will work for you (note that you need to Dim tr (with a different variable name, if you like) and use it in multiple places, but unlike in some languages you don't need to set up objects for the different methods.
Public Shared Function SaveNewIncident(ByVal clientName As String, dateStart As Date, dateEnd As Date, ByVal incidentProblem As String, ByVal timeStart As String, ByVal timeEnd As String,
ByVal incidentSolved As Boolean, ByVal incidentSolution As String, _con As OleDbConnection)
Dim tr As OleDbTransaction = Nothing
Try
Dim Dc As New OleDbCommand
Dc.Connection = _con
tr = _con.BeginTransaction()
Dc.CommandType = CommandType.Text
Dc.CommandText = "INSERT INTO dbo.tblIncidents VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?)"
Dc.Transaction = tr
Dc.Parameters.Add("#clientName", OleDbType.VarChar).Value = clientName
Dc.Parameters.Add("#dateStart", OleDbType.Date).Value = dateStart
Dc.Parameters.Add("#dateEnd", OleDbType.Date).Value = dateEnd
Dc.Parameters.Add("#incidentProblem", OleDbType.LongVarChar).Value = incidentProblem
Dc.Parameters.Add("#timeStart", OleDbType.VarChar).Value = timeStart
Dc.Parameters.Add("#timeEnd", OleDbType.VarChar).Value = timeEnd
Dc.Parameters.Add("#incidentSolved", OleDbType.Boolean).Value = incidentSolved
Dc.Parameters.Add("#incidentSolution", OleDbType.LongVarChar).Value = incidentSolution
Dim personID As Integer
Dc.CommandText = "SELECT SCOPE_IDENTITY() AS personID"
Dc.CommandType = CommandType.Text
personID = CType(Dc.ExecuteScalar(), Integer)
tr.Commit()
Catch ex As Exception
tr.Rollback()
Throw
End Try
End Function