如何使用 C# 运行 .sql 脚本，还需要为 .sql 文件中声明的参数传递值？

Question

Lets say I have following in my MyScript.Sql file

declare @city char(10)

set @city = 'Berlin'

If EXISTS( SELECT * FROM Customer where city = @city)
begin
 ---some stuff to do with the record---
end

using following code, i'm able to run above .sql file.

string sqlConnectionString = @"MyCS";

    FileInfo file = new FileInfo(@"(location of .sql file");

    string script = file.OpenText().ReadToEnd();

    SqlConnection conn = new SqlConnection(sqlConnectionString);

    Server server = new Server(new ServerConnection(conn));

    server.ConnectionContext.ExecuteNonQuery(script);
    file.OpenText().Close();

Now, I want to be able to dynamically pass the value of @city from my C# code to the .sql script instead of setting it's value in .sql file itself. How can I do that? Thanks!

Answer 1

I'm assuming there is some reason you're not just using a stored procedure for this and instead loading this from a file each time? That's really the way to do this if you're going to keep calling the same bit of code since you can pass the city as a parameter.

Anyway, you could just modify the SQL file and replace 'Berlin' with '{0}', then just do this:

string value = "Berlin"
script = string.Format(script, value); 

Or, just use the .Replace method:

script = script.Replace("Berlin", "New Value");

To add/use it as a stored procedure, you'd run a script in something like SQL Server Management Studio that looks like this:

CREATE PROCEDURE AddStuffIfCityExists
   @city char(10)
AS
BEGIN
   SET NOCOUNT ON;
   IF EXISTS( SELECT * FROM Customer where city = @city)
   BEGIN
       --some stuff to do with the record---
   END
END
GO

You can call it from your code like this:

using (SqlConnection conn = new SqlConnection(sqlConnectionString))
{
    using (var cmd = new SqlCommand("AddStuffIfCityExists", conn))
    {
        cmd.CommandType = System.Data.CommandType.StoredProcedure;
        cmd.Parameters.Add(new SqlParameter("@city", "Berlin"));
        cmd.ExecuteNonQuery();
    }
}

Answer 2

Here is how I got it to work. I have the SQL statement in a file, then have a WinForm that prompts the user for a value, runs the SQL and renders the results.

Here is the content of the sql script (note the @pM parameter):

SELECT 
    [computerName]
    ,[principleName]
    ,[appStarted]
    ,[appEnded]
    ,[appStatus]
    ,[appExecName]
    ,[appPID]
FROM 
    [dbo].[AppActivity]
WHERE
    [principleName] LIKE '%' + @pM + '%' AND
    [appStatus] = 'ACTIVE'

Here is the class:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Printing
{
    public partial class RunDBScript : Form
    {
        DataTable Dt = new DataTable();
        string strITSupportDB = Properties.Settings.Default.ITSupportDB;
        string strActiveAppSessions = Properties.Settings.Default.ActiveAppSessions;
        string SQLString;
        public RunDBScript()
        {
            InitializeComponent();
            FileInfo file = new FileInfo(@strActiveAppSessions);
            SQLString = file.OpenText().ReadToEnd();
        }

        private void RunDBScript_Load(object sender, EventArgs e)
        {

        }
        private void btnGetActiveSessions_Click(object sender, EventArgs e)
        {
            btnGetActiveSessions.Visible = false;
            try { Dt.Clear(); } catch { };
            try
            {
                using (SqlConnection connection = new SqlConnection(strITSupportDB))
                {
                    connection.Open();
                    SqlCommand command = new SqlCommand(SQLString, connection);
                    command.Parameters.Add("@pM", SqlDbType.NVarChar);
                    command.Parameters["@pM"].Value = txtUserName.Text.Trim();
                    SqlDataReader Dr = command.ExecuteReader();
                    Dt.Load(Dr);
                }
            }
            catch(Exception ex) { MessageBox.Show(ex.GetBaseException().ToString().Trim(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); }
            if(Dt.Rows.Count > 0) { dgvActiveSessions.DataSource = Dt; } else { dgvActiveSessions.DataSource = null; };
            btnGetActiveSessions.Visible = true;
        }
        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Close();
        }


    }
}