我需要执行四个查询,然后如果成功则必须返回 true,否则返回 false。
查询影响数据库,但函数返回 false
Private Function save_to_data()
Dim success As Boolean = False
Dim conn As OleDbConnection = GetDbConnection()
Dim total_due As Decimal = sanitize(txt_total_due.Text)
Dim amount_paid As Decimal = sanitize(txt_due.Text)
Dim discount As Decimal = sanitize(txt_discount.Text)
Dim balance As Decimal = sanitize(txt_balance.Text)
Dim cmdfoods As New OleDbCommand("UPDATE foods SET status='billed' WHERE customer_id = " & lbl_id.Text & "", conn)
Dim cmdservices As New OleDbCommand("UPDATE services SET status = 'billed' WHERE customer_id = " & lbl_id.Text & "", conn)
Dim cmdreservations As New OleDbCommand("UPDATE reservations SET nights = 4 WHERE customerid = " & lbl_id.Text & "", conn)
Dim bill As New OleDbCommand("INSERT INTO bills(customer_id, accomendation, food, service, total_due, amount_paid, discount, balance, transaction_date) VALUES " & _
"(" & lbl_id.Text & ", " & accomendation_total & ", " & food_total & ", " & service_total & ", " & total_due & ", " & amount_paid & " " & _
", " & discount & ", " & balance & ", '" & Date.Now & "')", conn)
conn.Open()
If cmdfoods.ExecuteNonQuery And cmdservices.ExecuteNonQuery And cmdreservations.ExecuteNonQuery And bill.ExecuteNonQuery Then
success = True
Else
success = False
End If
conn.Close()
Return success
End Function
最佳答案
代码还有许多其他问题(sql 注入(inject)、在多个命令之间共享连接),但这是朝着正确方向迈出的一步:
Try
conn.Open()
cmdfoods.ExecuteNonQuery()
cmdservices.ExecuteNonQuery()
cmdreservations.ExecuteNonQuery()
bill.ExecuteNonQuery()
success = True
Catch
success = False
Finally
conn.Close()
End Try
更完整的解决方案:
Private Function save_to_data()
Dim sql As String = _
"UPDATE foods SET status='billed' WHERE customer_id = ? ;" & _
"UPDATE services SET status = 'billed' WHERE customer_id = ? ;" & _
"UPDATE reservations SET nights = 4 WHERE customerid = ? ;"
"INSERT INTO bills(" & _
"customer_id, accomendation, food, service, total_due, amount_paid, discount, balance, transaction_date" & _
") VALUES ( ?, ?, ?, ?, ?, ?, ?, ?, ?);"
Using conn As OleDbConnection = GetDbConnection(), _
cmd As New OleDbCommand(sql, conn)
cmd.Parameters.Add("food_customer_id", OleDbType.Integer).Value = lbl_id.Text
cmd.Parameters.Add("serv_customer_id", OleDbType.Integer).Value = lbl_id.Text
cmd.Parameters.Add("res_customer_id", OleDbType.Integer).Value = lbl_id.Text
cmd.Parameters.Add("bill_customer_id", OleDbType.Integer).Value = lbl_id.Text
cmd.Parameters.Add("accomendataion", OleDbType.VarChar).Value = accomendation_total
cmd.Parameters.Add("food_total", OleDbType.Decimal).Value = food_total
cmd.Parameters.Add("service_total", OleDbType.Decimal).Value = service_total
cmd.Parameters.Add("total_due", OleDbType.Decimal).Value = total_due
cmd.Parameters.Add("amount_paid", OleDbType.Decimal).Value = amount_paid
cmd.Parameters.Add("discount", OleDbType.Decimal).Value = discount
cmd.Parameters.Add("balance", OleDbType.Decimal).Value = balance
cmd.Parameters.Add("transaction_date", OleDbType.Date).Value = Date.Now
conn.Open()
Return (cmd.ExecuteNonQuery() > 0)
End Using
End Function
关于vb.net - 如何一次执行四个查询然后检查成功或失败?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30848456/