Update demo

Src/Asp.Net/MySqlTest/UserTestCases/Cases/Demo9_EntityMain.cs

@@ -0,0 +1,46 @@
+using SqlSugar;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OrmTest
+{
+    public class Demo9_EntityMain
+    {
+        public static void Init()
+        {
+            Console.WriteLine("");
+            Console.WriteLine("#### EntityMain Start ####");
+
+            SqlSugarClient db = new SqlSugarClient(new ConnectionConfig()
+            {
+                DbType = DbType.MySql,
+                ConnectionString = Config.ConnectionString,
+                InitKeyType = InitKeyType.Attribute,
+                IsAutoCloseConnection = true,
+                AopEvents = new AopEvents
+                {
+                    OnLogExecuting = (sql, p) =>
+                    {
+                        Console.WriteLine(sql);
+                        Console.WriteLine(string.Join(",", p?.Select(it => it.ParameterName + ":" + it.Value)));
+                    }
+                }
+            });
+            var entityInfo = db.EntityMaintenance.GetEntityInfo<Order>();
+            foreach (var column in entityInfo.Columns)
+            {
+                Console.WriteLine(column.DbColumnName);
+            }
+
+            var dbColumnsName = db.EntityMaintenance.GetDbColumnName<EntityMapper>("Name");
+
+            var dbTableName = db.EntityMaintenance.GetTableName<EntityMapper>();
+
+            //more https://github.com/sunkaixuan/SqlSugar/wiki/9.EntityMain
+            Console.WriteLine("#### EntityMain End ####");
+        }
+    }
+}