sqlSugar的使用---入门
Posted yxcn
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了sqlSugar的使用---入门相关的知识,希望对你有一定的参考价值。
一,新建.net core web项目
二. 项目引入包:sqlSugarCore
三.创建两个表:user, department
四. 新建model(不一定需要与table相同,使用[SugarTable("tableName")]进行model与table的绑定)
namespace SqlSugarTest01.Models { [SugarTable("user")] public class UserModel { [SugarColumn(IsPrimaryKey =true,IsIdentity =true)]//如果是主键,此处必须指定,否则会引发InSingle(id)方法异常。 public int id { get; set; } public string userName { get; set; } public string userPassword { get; set; } public int age { get; set; } public DateTime regTime { get; set; } public int departmentId { get; set; } } }
5.编写代码进行数据库操作,此处为了简便,我书写在HomeController中,开辟了一个方法区,在Index的return view()之前调用,以便进行调试。
(1)查询语句
public void SqlConnection() { //创建连接实体对象 SqlSugarClient db = new SqlSugarClient( new ConnectionConfig() { ConnectionString = "server=localhost;port=3307;uid=root;pwd=root;database=testsqlsugar", DbType = DbType.mysql,//设置数据库类型 IsAutoCloseConnection = true,//自动释放数据库,如果存在事务,在事务结束之后释放。 InitKeyType = InitKeyType.Attribute//从实体特性中读取主键自增列信息 }); //aop监听sql,此段会在每一个"操作语句"执行时都进入....eg:getbyWhere这里会执行两次 db.Aop.OnLogExecuting = (sql, pars) => { string sqlStempt = sql + "参数值:" + db.Utilities.SerializeObject(pars.ToDictionary(it => it.ParameterName, it => it.Value)); }; /*查询---单表*/ var list = db.Queryable<UserModel>().ToList();//查询所有 var getById = db.Queryable<UserModel>().InSingle(1);//根据主键查询(model中必须同步标识主键[SugarColumn(IsPrimaryKey =true,IsIdentity =true)]) var total = 0; var getbyWhere = db.Queryable<UserModel>().Where(it => it.age == 18).ToPageList(1, 2, ref total);//根据条件查询/分页. /*查询---多表*/ var list0 = db.Queryable<UserModel, DepartmentModel>((user, dep) => new object[] { JoinType.Left,user.departmentId == dep.id}).Select((user, dep) => new { Id = user.id, depId = user.departmentId, name = user.userName }).ToList(); //生成的sql: SELECT `user`.`id` AS `Id` , `user`.`departmentId` AS `depId` , `user`.`userName` AS `name` FROM `user` user Left JOIN `department` dep ON( `user`.`departmentId` = `dep`.`id` ) //可用预先定义好的dto类自动填充select结果集,自动填充会比较依赖字段取名规则 List<userDepDto> list1 = db.Queryable<UserModel, DepartmentModel>((user, dep) => new object[] { JoinType.Left, user.departmentId == dep.id }).Select<userDepDto>().ToList(); List<userDepDto> list2 = db.Queryable<UserModel, DepartmentModel>((user, dep) => new object[] { JoinType.Left, user.departmentId == dep.id }).Select((user, dep) => new userDepDto { Id = dep.id, userName = user.userName, regTime = user.regTime, name = dep.name }).ToList(); //三表查询,返回完整的三表对象。 var list3 = db.Queryable<UserModel, DepartmentModel, UserInfoModel>((user, dep, userinfo) => new object[] { JoinType.Left, user.departmentId == dep.id, JoinType.Left, user.id == userinfo.UserId }).Where((user, dep, userinfo) => user.age == 18 || dep.id == 1 || userinfo.Sex == "男") .OrderBy((user) => user.id).OrderBy((user, dep) => dep.id, OrderByType.Desc).Select((user, dep, userInfo) => new { user = user, dep = dep, userInfo = userInfo }).ToList(); //多表查询分页 var list4 = db.Queryable<UserModel, DepartmentModel>((user, dep) => new object[] { JoinType.Left, user.departmentId == dep.id }).Select((user, dep) => new userDepDto { Id = user.id, userName = user.userName, regTime = user.regTime, name = dep.name }).ToPageList(2, 2); //两个Queryable的join var q1 = db.Queryable<UserModel, DepartmentModel>((user, dep) => new object[] { JoinType.Left, user.departmentId == dep.id }).Select((user,dep)=>new userDepDto() { Id=user.id,userName=user.userName,regTime=user.regTime,name=dep.name}); var q2 = db.Queryable<UserModel>(); // inner join var innerJoinList = db.Queryable(q1, q2, (j1, j2) => j1.Id == j2.id).Select((j1, j2) => j1).ToList(); //left join var leftJoinList = db.Queryable(q1, q2, JoinType.Left, (j1, j2) => j1.Id == j2.id).Select((j1,j2)=>j1).ToList(); }
以上是关于sqlSugar的使用---入门的主要内容,如果未能解决你的问题,请参考以下文章