SQL Server 连接字符串中的“初始目录”有何意义

SQL Server 连接字符串中的“初始目录”有何意义？

csharp
using System;
using System.Data.SqlClient;
class Program
{
    static void Main()
    {
        string connectionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password";
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            try
            {
                connection.Open();
                Console.WriteLine("成功连接到数据库！");
            }
            catch (Exception ex)
            {
                Console.WriteLine("连接数据库失败：{0}", ex.Message);
            }
        }
    }
}