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[英]Get an identity value in a controller for INSERT (Execute Insert command and return inserted Id in Sql)
[英]Execute Insert command and return inserted Id in Sql
我在 MVC 4 中使用 C# 將一些值插入到 SQL 表中。實際上,我想插入值並返回最后插入記錄的“ID”。 我使用以下代碼。
public class MemberBasicData
{
public int Id { get; set; }
public string Mem_NA { get; set; }
public string Mem_Occ { get; set; }
}
插入時 ID 在數據庫中自動遞增。
public int CreateNewMember(string Mem_NA, string Mem_Occ )
{
using (SqlConnection con=new SqlConnection(Config.ConnectionString))
{
using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) VALUES(@na,@occ)",con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
int modified = cmd.ExecuteNonQuery();
if (con.State == System.Data.ConnectionState.Open) con.Close();
return modified;
}
}
}
我知道ExecuteNonQuery
表示影響行的數字。 而不是我使用
int modified = (int)cmd.ExecuteScalar();
但它不起作用。 請幫我解決這個問題。 是否有像cmd.ExecuteInsertAndGetID()
這樣的代碼(不適用於我的代碼)。
以下解決方案適用於 sql server 2005 及更高版本。 您可以使用輸出來獲取必填字段。 代替 id,您可以編寫要返回的密鑰。 像這樣做
FOR SQL SERVER 2005 及以上
using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) output INSERTED.ID VALUES(@na,@occ)",con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
int modified =(int)cmd.ExecuteScalar();
if (con.State == System.Data.ConnectionState.Open)
con.Close();
return modified;
}
}
對於以前的版本
using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) VALUES(@na,@occ);SELECT SCOPE_IDENTITY();",con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
int modified = Convert.ToInt32(cmd.ExecuteScalar());
if (con.State == System.Data.ConnectionState.Open) con.Close();
return modified;
}
}
將查詢更改為
"INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) VALUES(@na,@occ); SELECT SCOPE_IDENTITY()"
這將返回最后插入的 ID,然后您可以使用ExecuteScalar
SQL Server 存儲過程:
CREATE PROCEDURE [dbo].[INS_MEM_BASIC]
@na varchar(50),
@occ varchar(50),
@New_MEM_BASIC_ID int OUTPUT
AS
BEGIN
SET NOCOUNT ON;
INSERT INTO Mem_Basic
VALUES (@na, @occ)
SELECT @New_MEM_BASIC_ID = SCOPE_IDENTITY()
END
C#代碼:
public int CreateNewMember(string Mem_NA, string Mem_Occ )
{
// values 0 --> -99 are SQL reserved.
int new_MEM_BASIC_ID = -1971;
SqlConnection SQLconn = new SqlConnection(Config.ConnectionString);
SqlCommand cmd = new SqlCommand("INS_MEM_BASIC", SQLconn);
cmd.CommandType = CommandType.StoredProcedure;
SqlParameter outPutVal = new SqlParameter("@New_MEM_BASIC_ID", SqlDbType.Int);
outPutVal.Direction = ParameterDirection.Output;
cmd.Parameters.Add(outPutVal);
cmd.Parameters.Add("@na", SqlDbType.Int).Value = Mem_NA;
cmd.Parameters.Add("@occ", SqlDbType.Int).Value = Mem_Occ;
SQLconn.Open();
cmd.ExecuteNonQuery();
SQLconn.Close();
if (outPutVal.Value != DBNull.Value) new_MEM_BASIC_ID = Convert.ToInt32(outPutVal.Value);
return new_MEM_BASIC_ID;
}
我希望這些對你有幫助......
如果你願意,你也可以使用它......
public int CreateNewMember(string Mem_NA, string Mem_Occ )
{
using (SqlConnection con=new SqlConnection(Config.ConnectionString))
{
int newID;
var cmd = "INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) VALUES(@na,@occ);SELECT CAST(scope_identity() AS int)";
using(SqlCommand cmd=new SqlCommand(cmd, con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
newID = (int)insertCommand.ExecuteScalar();
if (con.State == System.Data.ConnectionState.Open) con.Close();
return newID;
}
}
}
USE AdventureWorks2012;
GO
IF OBJECT_ID(N't6', N'U') IS NOT NULL
DROP TABLE t6;
GO
IF OBJECT_ID(N't7', N'U') IS NOT NULL
DROP TABLE t7;
GO
CREATE TABLE t6(id int IDENTITY);
CREATE TABLE t7(id int IDENTITY(100,1));
GO
CREATE TRIGGER t6ins ON t6 FOR INSERT
AS
BEGIN
INSERT t7 DEFAULT VALUES
END;
GO
--End of trigger definition
SELECT id FROM t6;
--IDs empty.
SELECT id FROM t7;
--ID is empty.
--Do the following in Session 1
INSERT t6 DEFAULT VALUES;
SELECT @@IDENTITY;
/*Returns the value 100. This was inserted by the trigger.*/
SELECT SCOPE_IDENTITY();
/* Returns the value 1. This was inserted by the
INSERT statement two statements before this query.*/
SELECT IDENT_CURRENT('t7');
/* Returns value inserted into t7, that is in the trigger.*/
SELECT IDENT_CURRENT('t6');
/* Returns value inserted into t6. This was the INSERT statement four statements before this query.*/
-- Do the following in Session 2.
SELECT @@IDENTITY;
/* Returns NULL because there has been no INSERT action
up to this point in this session.*/
SELECT SCOPE_IDENTITY();
/* Returns NULL because there has been no INSERT action
up to this point in this scope in this session.*/
SELECT IDENT_CURRENT('t7');
/* Returns the last value inserted into t7.*/
SELECT SCOPE_IDENTITY() AS 'Identity'
這將返回僅在當前范圍內插入的標識值
SELECT @@IDENTITY AS 'Identity';
這不限於特定范圍因此這將返回標識列的最新值,而不一定是來自同一范圍的標識值。
如果您使用 EF:
Class Person{
public int Id {get;set;}
public string Name {get;set;}
}
您設置名稱值:
Person p = new Person(){
Name = "James"
};
DbContext.Persons.Add(p);
DbContext.SaveChanges();
//p.Id = new Id from database
//p.Name = James
您只需保存它,您就會從數據庫中獲得 Id。
可以在 Insert 查詢鏈接中使用OUTPUT Inserted.Id
:
INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) OUTPUT INSERTED.Id VALUES(@na,@occ);
將響應存儲在結果變量中,然后讀取 result[0].Id,或者可以使用 ExecuteSingle 並直接讀取 result.Id 以訪問插入的 id 或任何其他 col 數據。
using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) " +
"VALUES(@na,@occ);SELECT SCOPE_IDENTITY();",con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
int modified = cmd.ExecuteNonQuery();
if (con.State == System.Data.ConnectionState.Open) con.Close();
return modified;
}
SCOPE_IDENTITY :返回插入到同一范圍內的標識列中的最后一個標識值。 有關更多詳細信息,請訪問http://technet.microsoft.com/en-us/library/ms190315.aspx
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