C# MySQL Dapper insert delete select update data from table
Install dapper
using Dapper; using MySql.Data.MySqlClient; namespace ConsoleApp87 { internal class Program { static string connStr = @"Server=servernamevalue;user id=usernamevalue;password=passwordvalue;database=databasenamevalue;"; static void Main(string[] args) { DapperDeleteData(); Console.ReadLine(); } static void DapperDeleteData() { using (MySqlConnection conn = new MySqlConnection(connStr)) { conn.Open(); Console.WriteLine(conn.State); string selectStr = "select * from t1 order by id desc limit 1;"; var bk = conn.Query<Book>(selectStr).FirstOrDefault(); Console.WriteLine(bk.ToString()); string deleteSQL = "delete from t1 where id=@id"; int deleteResult = conn.Execute(deleteSQL, bk); Console.WriteLine($"DeleteResult:{deleteResult}"); bk = conn.Query<Book>(selectStr).FirstOrDefault(); Console.WriteLine(bk.ToString()); } } static void DapperUpdateData() { using (MySqlConnection conn = new MySqlConnection(connStr)) { conn.Open(); Console.WriteLine(conn.State); string selectStr = "select * from t1 order by id desc limit 1"; Book bk = conn.Query<Book>(selectStr).FirstOrDefault(); Console.WriteLine(bk.ToString()); bk.FirstName = $"{bk.FirstName}_Max"; bk.LastName = $"{bk.LastName}_Max"; string updateSQL = "update t1 set firstname=@firstname,lastname=@lastname where id=@id"; int updatedResult = conn.Execute(updateSQL, bk); Console.WriteLine($"UpdatedResult:{updatedResult}"); bk = conn.Query<Book>(selectStr).FirstOrDefault(); Console.WriteLine(bk.ToString()); } } static void DapperInsertData() { using (MySqlConnection conn = new MySqlConnection(connStr)) { conn.Open(); Console.WriteLine(conn.State); string selectStr = "select id from t1 order by id desc limit 1"; int maxId = conn.Query<int>(selectStr).FirstOrDefault(); Console.WriteLine($"Old maxId:{maxId}"); int newId = maxId + 1; Book bk = new Book() { FirstName=$"FirstName_{newId}", LastName=$"LastName_{newId}" }; string insertSql = "insert into t1 (firstname,lastname) values (@firstname,@lastname)"; int insertedResult= conn.Execute(insertSql, bk); Console.WriteLine($"Inserted Result:{insertedResult}"); maxId = conn.Query<int>(selectStr).FirstOrDefault(); Console.WriteLine($"New MaxId:{maxId}"); } } static void DapperReadData() { using (MySqlConnection conn = new MySqlConnection(connStr)) { conn.Open(); Console.WriteLine(conn.State); string selectStr = "select * from t1 where id in (1,2,3);"; List<Book> booksList = conn.Query<Book>(selectStr).ToList(); if (booksList != null && booksList.Any()) { foreach (var bk in booksList) { Console.WriteLine(bk.ToString()); } } } } public class Book { public int Id { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public override string ToString() { return $"Id:{Id},FirstName:{FirstName},LastName:{LastName}"; } } } }
use mydb; select * from t1 order by id desc limit 1;
分类:
MySQL
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2020-09-27 dapper .IDbConnection.Query<T>(selectSQL);