如何在单个 SQL 连接中运行多个 SQL 命令?

How to run multiple SQL commands in a single SQL connection?(如何在单个 SQL 连接中运行多个 SQL 命令?)

问题描述

我正在创建一个项目，我需要在单个 SQL 连接中运行 2-3 个 SQL 命令.这是我写的代码:

I am creating a project in which I need to run 2-3 SQL commands in a single SQL connection. Here is the code I have written:

SqlConnection con = new SqlConnection(@"Data Source=(LocalDB)v11.0;AttachDbFilename=|DataDirectory|project.mdf;Integrated Security=True");
con.Open();
SqlCommand cmd = new SqlCommand("select *  from " + mytags.Text + " ", con);
SqlDataReader rd = cmd.ExecuteReader();
if (rd.Read())
{
    con.Close();
    con.Open();
    SqlCommand cmd1 = new SqlCommand("insert into " + mytags.Text + " values ('fname.lname@gmail.com','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','"+mytags.Text+"')", con);
    cmd1.ExecuteNonQuery();
    label.Visible = true;
    label.Text = "Date read and inserted";
}
else
{
    con.Close();
    con.Open();
    SqlCommand cmd2 = new SqlCommand("create table " + mytags.Text + " ( session VARCHAR(MAX) , Price int , Description VARCHAR(MAX), Date VARCHAR(20),tag VARCHAR(10))", con);
    cmd2.ExecuteNonQuery();
    con.Close();
    con.Open();
    SqlCommand cmd3 = new SqlCommand("insert into " + mytags.Text + " values ('" + Session + "','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','" + mytags.Text + "')", con);
    cmd3.ExecuteNonQuery();
    label.Visible = true;
    label.Text = "tabel created";
    con.Close();
}

我已尝试消除错误，但我发现连接不会进入其他状态.请检查代码并建议是否有任何错误或任何其他解决方案.

I have tried to remove the error and I got that the connection is not going to else condition. Please review the code and suggest if there is any mistake or any other solution for this.

推荐答案

只需更改SqlCommand.CommandText，而不是每次都创建一个新的SqlCommand.无需关闭并重新打开连接.

Just change the SqlCommand.CommandText instead of creating a new SqlCommand every time. There is no need to close and reopen the connection.

// Create the first command and execute
var command = new SqlCommand("<SQL Command>", myConnection);
var reader = command.ExecuteReader();

// Change the SQL Command and execute
command.CommandText = "<New SQL Command>";
command.ExecuteNonQuery();

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