[英]Catch Id (INT AUTO INCREMENT) of a Record after INSERT INTO Statement
[英]Retrieve Auto Increment ID from SQL Database after Insert Statement
下面是我在將數據插入數據庫后檢索自動增量 ID 的代碼。
但是,在將數據插入數據庫之前,我獲得了自動增量 ID。
插入數據庫后如何獲得自動增量ID?
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
RetrievePRReqID();
}
}
//獲取ID方法
private void RetrievePRReqID()
{
try
{
string query = "Select IDENT_CURRENT('tblPRRequest')";
if (sqlCon.State == ConnectionState.Closed)
{
sqlCon.Open();
}
SqlCommand cmd = new SqlCommand(query, sqlCon);
SqlDataReader reader = cmd.ExecuteReader();
while(reader.Read())
{
int value = int.Parse(reader[0].ToString()) ;
txt_PRNO.Text = value.ToString();
}
}
catch(Exception)
{
throw;
}
finally
{
if(con.State == ConnectionState.Open)
{
con.Close();
}
}
}
//請求按鈕方法
protected void btn_Request(object sender, EventArgs e)
{
string insertCmd = "INSERT INTO tblPRRequest (RequestTo,RequestFrom,RequestedByName) " +
"VALUES (@RequestTo,@RequestFrom,@RequestedByName)";
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
using (SqlCommand sqlcmd = new SqlCommand(insertCmd, conn))
{
sqlcmd.Parameters.Clear();
SqlCommand sqlCmd = new SqlCommand(insertCmd, sqlCon);
sqlcmd.Parameters.AddWithValue("@RequestTo", lblPurchasingDept.Text);
sqlcmd.Parameters.AddWithValue("@RequestFrom", ddlDept.SelectedItem.Text);
sqlcmd.Parameters.AddWithValue("@RequestedByName", SUserName.Text);
sqlcmd.ExecuteNonQuery();
}
}
***//After Insert into the table, I want to retrieve latest generated Auto Increment ID in here.***
}
嘗試這個:
protected void btn_Request(object sender, EventArgs e)
{
string insertCmd = "INSERT INTO tblPRRequest (RequestTo,RequestFrom,RequestedByName) " +
"VALUES (@RequestTo,@RequestFrom,@RequestedByName)";
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
using (SqlCommand sqlcmd = new SqlCommand(insertCmd, conn))
{
sqlcmd.Parameters.Clear();
SqlCommand sqlCmd = new SqlCommand(insertCmd, sqlCon);
sqlcmd.Parameters.AddWithValue("@RequestTo", lblPurchasingDept.Text);
sqlcmd.Parameters.AddWithValue("@RequestFrom", ddlDept.SelectedItem.Text);
sqlcmd.Parameters.AddWithValue("@RequestedByName", SUserName.Text);
sqlcmd.Parameters.Add("@ID", SqlDbType.Int).Direction = ParameterDirection.Output;
sqlcmd.ExecuteNonQuery();
}
}
***//After Insert into the table, I want to retrieve latest generated Auto Increment ID in here.***
sqlcmd.Parameters["@ID"].value; // Access it like this
}
如果您可以將ExecuteNonQuery
為ExecuteScalar
,那么它會更容易: ExecuteScalar、ExecuteReader 和 ExecuteNonQuery 之間有什么區別?
如 SQL Server 文檔中所述https://docs.microsoft.com/en-us/sql/t-sql/queries/output-clause-transact-sql?view=sql-server-ver15
OUTPUT 子句可用於在 INSERT 或 UPDATE 操作后檢索標識或計算列的值。
你必須改變你的 SQL 語句
INSERT INTO tblPRRequest (RequestTo,RequestFrom,RequestedByName)
OUTOUT inserted.ID
-------^^^^^^^^_^^
VALUES (@RequestTo,@RequestFrom,@RequestedByName)
現在您可以使用 ExecuteScalar 來獲取插入的值
protected void btn_Request(object sender, EventArgs e)
{
int id= 0;
string insertCmd = "INSERT INTO tblPRRequest (RequestTo,RequestFrom,RequestedByName) " +
"output inserted.ID" +
"VALUES (@RequestTo,@RequestFrom,@RequestedByName)";
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
using (SqlCommand sqlcmd = new SqlCommand(insertCmd, conn))
{
sqlcmd.Parameters.AddWithValue("@RequestTo", lblPurchasingDept.Text);
sqlcmd.Parameters.AddWithValue("@RequestFrom", ddlDept.SelectedItem.Text);
sqlcmd.Parameters.AddWithValue("@RequestedByName", SUserName.Text);
id = (int)sqlcmd.ExecuteScalar(); //the result is of Object type, cast it safely
}
}
Debug.WriteLine(id.ToString()); // Access it like this
}
通過參考@Mx.Wolf 的示例答案,我做了一些修改以獲得正確的答案,下面是有效的代碼:
protected void btn_Request(object sender, EventArgs e)
{
object id ;
string insertCmd = "INSERT INTO tblPRRequest (RequestTo,RequestFrom,RequestedByName) " +
"output inserted.PRReqID " +
"VALUES (@RequestTo,@RequestFrom,@RequestedByName)";
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
using (SqlCommand sqlcmd = new SqlCommand(insertCmd, conn))
{
sqlcmd.Parameters.AddWithValue("@RequestTo", lblPurchasingDept.Text);
sqlcmd.Parameters.AddWithValue("@RequestFrom", ddlDept.SelectedItem.Text);
sqlcmd.Parameters.AddWithValue("@RequestedByName", SUserName.Text);
id = sqlcmd.ExecuteScalar(); //the result is of Object type, cast it safely
}
}
Debug.WriteLine(id.ToString()); // Access it like this
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