通过属性的方法设置别名表和别名字段

   //通过属性的方法设置别名表和别名字段（主键和自添列都无需设置 SQLSUGAR会帮你自动处理）
    //注意:【属性映射和 (SetMappingTables、SetMappingColumns)方式映射 2种选其中一，不清楚底层缓存机质不建议同时使用】
    public class AttributesMapping : IDemos
    {
        public void Init()
        {
            Console.WriteLine("启动AttributesMapping.Init");
            using (var db = DBManager.GetInstance())
            {
                //查询
                var list = db.Queryable<TestStudent>()
                    .Where(it => it.className.Contains("小")).OrderBy(it => it.classSchoolId).Select<V_Student>(it => new V_Student() { id = it.classId, name = it.className }).ToList();
                var list2 = db.Queryable<TestStudent>()
                    .JoinTable<TestSchool>((s1, s2) => s1.classSchoolId == s2.classId)
                    .OrderBy<TestSchool>((s1, s2) => s1.classId)
                    .Select<TestStudent, TestSchool, V_Student>((s1, s2) => new V_Student() { id = s1.classId, name = s1.className, SchoolName = s2.className }).ToList();
                //添加
                TestStudent s = new TestStudent();
                s.className = "属性名";
                s.classSchoolId = 1;
                var id = db.Insert(s);
                s.classId = id.ObjToInt();

                db.SqlBulkCopy(new List<TestStudent>() { s });

                //更新
                db.Update(s);
                db.Update<TestStudent, int>(s, 100);
                db.Update<TestStudent>(s, it => it.classId == 100);
                db.SqlBulkReplace(new List<TestStudent>() { s });
                //删除
                db.Delete<TestStudent>(it => it.classId == 100);
                //根据实体赋值实体一定要有主键，并且要有值。
                db.Delete(new TestStudent() {  classId = 200 });
            }
        }
        /// <summary>
        /// 属性只作为初始化映射，SetMappingTables和SetMappingColumns可以覆盖
        /// </summary>
        [SugarMapping(TableName = "Student")]
        public class TestStudent
        {
            [SugarMapping(ColumnName = "id")]
            public int classId { get; set; }
            [SugarMapping(ColumnName = "name")]
            public string className { get; set; }
            [SugarMapping(ColumnName = "sch_id")]
            public int classSchoolId { get; set; }
            public int isOk { get; set; }
            /// <summary>
            /// 数据库并没有这一列
            /// </summary>
            public string errorField { get; set; }
        }
 
        [SugarMapping(TableName = "School")]
        public class TestSchool
        {
            [SugarMapping(ColumnName = "id")]
            public int classId { get; set; }
            [SugarMapping(ColumnName = "name")]
            public string className { get; set; }
            public int AreaId = 1;
        }
    }
    public class DBManager
    {
        public static SqlSugarClient GetInstance()
        {
            var db = new SqlSugarClient(SugarDao.ConnectionString);
            db.IsEnableAttributeMapping = true;//启用属性映射
            db.IsIgnoreErrorColumns = true;//忽略非数据库列
            db.IsEnableLogEvent = true;//启用日志事件
            db.LogEventStarting = (sql, par) => { Console.WriteLine(sql + " " + par + "\r\n"); };

            return db;
        }
    }