On Error GoTo exectuesql_error
    stokens = Split(sql)
    If InStr("INSER,DELETE,UPDATE", UCase(stokens(0))) Then
        mycon.Execute sql
    Else
        Set rst = New ADODB.Recordset
        rst.Open Trim(sql), mycon, adOpenKeyset, adLockOptimistic
        Set ExecuteSQL = rst
    End If
exectuesql_exit:
    Set rst = Nothing
    Set mycon = Nothing
    Exit Function
exectuesql_error:
    Resume exectuesql_exit
End Function
请教各位大侠，错误跳转语句的解释，可否帮忙逐句解释下，最近分少，但请帮帮忙啊，谢谢了

可否详细说明下stokens = Split(sql)
    If InStr("INSER,DELETE,UPDATE", UCase(stokens(0))) Then
        mycon.Execute sql
    Else
        Set rst = New ADODB.Recordset
        rst.Open Trim(sql), mycon, adOpenKeyset, adLockOptimistic
        Set ExecuteSQL = rst
    End If
这几个语段的意思，谢谢