我有一个appointments表，其中有一个[personid]和一个[appdate]数据类型的datetime(2)列。我想添加一个约束，以防止任何personid在任何一天都获得多个约会。
我尝试过，但是没有用
ALTER TABLE dbo.tblappointments
ADD CONSTRAINT SingleApp UNIQUE (PersonID, CAST(Appdate AS DATE))
谢谢。
答案 0 :(得分：2)
我想您可以创建一个计算列并将其用作索引。
add-symbol-file如果您不使用["status": "1",
"error": false,
"data": [
{
"order_id": "11",
"order_unique_id": "ORDR-1001",
"store_name": "24X7",
"otp_store": "781103",
"product": [
"Product One",
"Product Two"
],
"qty": [
"1",
"3"
],
"user_details": {
"name": "test",
"number": "98145314586",
"landmark": "test",
"area": "Bow East",
"pincode": "E3 9EG",
"place": "Home"
},
"status": "2",
"date": "2018-12-13",
"time": "14:37:57"
}]
struct RunnerStatus: Decodable {
var status: String
var error: Bool
var data: [Runner]
}
struct Runner: Decodable {
var order_id: String
var order_unique_id: String
var store_name: String
var otp_store: String
var product: [Product]
var qty: [Quantity]
var user_details: [UserDetails]
var status: String
var date: String
var time: String
}
struct Product: Decodable {
var ProductName: String
}
struct Quantity: Decodable {
var qty: String
}
struct UserDetails: Decodable {
var name: String
var number: String
var landmark: String
var area: String
var pincode: String
var place: String
}
，则每次访问该列时都会计算该值