Question

我有两张桌子：

create table Clients
(
     id_client int not null identity(1,1) Primary Key,
     name_client varchar(10) not null,
     phone_client int not null
)

create table Sales
(
     id_sale int not null identity(1,1) Primary Key,
     date_sale date not null, 
     total_sale float not null
     id_clients int not null identity(1,1) Foreign Key references Clients
)

因此，让我们插入客户端（＆＃39; Ralph＆＃39; 00000000），id_client将为1（显然）。问题是：我如何将1插入销售？

Answer 1

首先 - 您无法在任何表格中将两列定义为identity - 您将收到错误

Msg 2744，Level 16，State 2，Line 1
为表＆＃39; Sales＆＃39;指定了多个标识列。每个表只允许一个标识列。

因此，您将无法实际创建该Sales表。

id_clients表中的Sales列引用 identity列 - 但本身应该不定义作为身份 - 它可以获得客户的任何价值。

create table Sales
(
     id_sale int not null identity(1,1) Primary Key,
     date_sale date not null, 
     total_sale float not null
     id_clients int not null foreign key references clients(id_client)
)

-- insert a new client - this will create an "id_client" for that entry
insert into dbo.Clients(name_client, phone_client)
values('John Doe', '+44 44 444 4444')

-- get that newly created "id_client" from the INSERT operation
declare @clientID INT = SCOPE_IDENTITY()

-- insert the new "id_client" into your sales table along with other values
insert into dbo.Sales(......, id_clients)
values( ......., @clientID)

如何将标识值插入另一个表

1 个答案: