初学SqlHelper - 实现增删改查
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1 //数据库连接字符串 2 public static readonly string constr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString; 3 4 //打开数据库 5 public static SqlConnection OpenConnection() 6 { 7 SqlConnection conn = new SqlConnection(constr); 8 conn.Open(); 9 return conn; 10 } 11 12 //执行不返回结果的sql，用于插入和更新，删除 13 public static int ExecuteNonQuery(string cmdText, params SqlParameter[] parameters) 14 { 15 using (SqlConnection conn = new SqlConnection(constr)) 16 { 17 conn.Open(); 18 return ExecuteNonQuery(conn, cmdText, parameters); 19 } 20 } 21 22 //上面方法的重载方法 23 public static int ExecuteNonQuery(SqlConnection conn, string cmdText, params SqlParameter[] parameters) 24 { 25 using (SqlCommand cmd = conn.CreateCommand()) 26 { 27 cmd.CommandText = cmdText; 28 cmd.Parameters.AddRange(parameters); 29 return cmd.ExecuteNonQuery(); 30 } 31 } 32 33 //返回对象类型的sql查询，对象单个数据记录的中的某个值，或者count(*)计算的结果，在分页中会经常用到。 34 public static object ExecuteScalar(string cmdText, params SqlParameter[] parameters) 35 { 36 using (SqlConnection conn = new SqlConnection(constr)) 37 { 38 conn.Open(); 39 return ExecuteScalar(conn, cmdText, parameters); 40 } 41 } 42 43 //以上方法的重载方法 44 public static object ExecuteScalar(SqlConnection conn, string cmdText, params SqlParameter[] parameters) 45 { 46 using (SqlCommand cmd = conn.CreateCommand()) 47 { 48 cmd.CommandText = cmdText; 49 cmd.Parameters.AddRange(parameters); 50 return cmd.ExecuteScalar(); 51 } 52 } 53 54 //获得数据表格的查询 55 public static DataTable ExecuteDataTable(string cmdText, params SqlParameter[] parameters) 56 { 57 using (SqlConnection conn = new SqlConnection(constr)) 58 { 59 conn.Open(); 60 return ExecuteDataTable(conn, cmdText, parameters); 61 } 62 } 63 64 //以上方法的重载 65 public static DataTable ExecuteDataTable(SqlConnection conn, string cmdText, params SqlParameter[] parameters) 66 { 67 using (SqlCommand cmd = conn.CreateCommand()) 68 { 69 cmd.CommandText = cmdText; 70 cmd.Parameters.AddRange(parameters); 71 using (SqlDataAdapter adapter = new SqlDataAdapter(cmd)) 72 { 73 DataTable dt = new DataTable(); 74 adapter.Fill(dt); 75 return dt; 76 } 77 } 78 }
1 /// <summary> 2 /// 查询表中总记录 3 /// </summary> 4 /// <param name="data"></param> 5 /// <returns></returns> 6 public async Task<ActionResult> ScalarData(ContactModel data) 7 { 8 string sql = "select count(*) from Contact"; 9 var DataSource = SqlHelper.ExecuteScalar(sql); 10 return ReturnJson(new ResponseModel("0000", "成功", "共有记录"+DataSource.ToString()+"条")); 11 } 12 /// <summary> 13 /// 分页查询表中数据 14 /// </summary> 15 /// <param name="data"></param> 16 /// <returns></returns> 17 public async Task<ActionResult> SelectPageData(ContactModel data) 18 { 19 int pageindex = data.pageindex; 20 int pagesize = data.pagesize; 21 string sql = "select top " + pagesize + " * from Contact where id not in (select top (" + pagesize * (pageindex - 1) + ") id from Contact)"; 22 var DataSource = SqlHelper.ExecuteDataTable(sql); 23 string JsonString = string.Empty; 24 JsonString = JsonConvert.SerializeObject(DataSource); 25 return ReturnJson(new ResponseModel("0000", "成功", JsonString)); 26 } 27 /// <summary> 28 /// 查询表中所有数据 29 /// </summary> 30 /// <param name="data"></param> 31 /// <returns></returns> 32 public async Task<ActionResult> SelectData(ContactModel data) 33 { 34 string sql = "select * from Contact"; 35 //string sql = "select * from Contact where Name=ISNULL(‘" + data.name + "‘,Name)"; 36 var DataSource = SqlHelper.ExecuteDataTable(sql); 37 38 //string sql = "select * from Contact where Name=ISNULL(@Name,Name)"; 39 //var DataSource = SqlHelper.ExecuteDataTable(sql, new SqlParameter("@Name", data.name)); 40 string JsonString = string.Empty; 41 JsonString = JsonConvert.SerializeObject(DataSource); 42 return ReturnJson(new ResponseModel("0000","成功", JsonString)); 43 } 44 /// <summary> 45 /// 在表中插入一条新的数据 46 /// </summary> 47 /// <param name="data"></param> 48 /// <returns></returns> 49 public async Task<ActionResult> InsertData(ContactModel data) 50 { 51 //string sql = "INSERT INTO Contact VALUES (‘"+ data.name+"‘,‘"+data.enrollmentDate+"‘)"; 52 string sql = "INSERT INTO Contact VALUES (@name, @enrollmentDate)"; 53 SqlParameter[] param = new SqlParameter[] { 54 new SqlParameter("@name",data.name), 55 new SqlParameter("@enrollmentDate",data.enrollmentDate), 56 }; 57 var DataSource = SqlHelper.ExecuteNonQuery(sql, param); 58 if (DataSource == 1) 59 { 60 return ReturnJson(new ResponseModel("0000", "成功", "")); 61 } 62 return ReturnJson(new ResponseModel("9999", "处理失败", "")); 63 } 64 /// <summary> 65 /// 根据id修改表中的数据 66 /// </summary> 67 /// <param name="data"></param> 68 /// <returns></returns> 69 public async Task<ActionResult> UpdateData(ContactModel data) 70 { 71 if (data.id == null) 72 { 73 return new HttpStatusCodeResult(HttpStatusCode.BadRequest); 74 } 75 //string sql = "UPDATE Contact SET Name = ‘"+ data.name + "‘,EnrollmentDate = ‘" + data.enrollmentDate + "‘ WHERE ID = " + data.id; 76 string sql = "UPDATE Contact SET Name = @name , EnrollmentDate = @enrollmentDate WHERE ID = @id"; 77 SqlParameter[] param = new SqlParameter[] { 78 new SqlParameter("@id",data.id), 79 new SqlParameter("@name",data.name), 80 new SqlParameter("@enrollmentDate",data.enrollmentDate), 81 }; 82 var DataSource = SqlHelper.ExecuteNonQuery(sql, param); 83 if (DataSource == 1) 84 { 85 return ReturnJson(new ResponseModel("0000", "成功", "")); 86 } 87 return ReturnJson(new ResponseModel("9999", "处理失败", "")); 88 } 89 /// <summary> 90 /// 根据id删除表中的数据 91 /// </summary> 92 /// <param name="data"></param> 93 /// <returns></returns> 94 public async Task<ActionResult> DeleteData(ContactModel data) 95 { 96 string sql = "DELETE FROM Contact WHERE ID = @id"; 97 SqlParameter[] param = new SqlParameter[] { 98 new SqlParameter("@id",data.id) 99 }; 100 var DataSource = SqlHelper.ExecuteNonQuery(sql, param); 101 if (DataSource == 1) 102 { 103 return ReturnJson(new ResponseModel("0000", "成功", "")); 104 } 105 return ReturnJson(new ResponseModel("9999", "处理失败", "")); 106 } 107 108 public JsonResult ReturnJson(ResponseModel response) 109 { 110 return this.Json(response, JsonRequestBehavior.AllowGet); 111 }
1 public class ContactModel 2 { 3 public int id { get; set; } 4 public string name { get; set; } 5 public string enrollmentDate { get; set; } 6 public int pageindex { get; set; } 7 public int pagesize { get; set; } 8 }
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