C#应用程序与数据库的集成几种方法

using Microsoft.Data.SqlClient;
using System.Xml;


namespace Fountain.WinConsole.OtherDemo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            // 创建 Connection 对象
            using (SqlConnection sqlConnection = new SqlConnection())
            {
                // 通过 ConnectionString 属性连接数据库
                sqlConnection.ConnectionString = "server=127.0.0.1,1433;Enlist=true;Pooling=true; uid=sa;pwd=sa123456;connection Timeout=30;database=CRMS;Max Pool Size=600";
                // 创建一个 SqlCommand 对象
                SqlCommand sqlCommand = sqlConnection.CreateCommand();
                // 命令的类型为Text
                sqlCommand.CommandType = System.Data.CommandType.Text;
                // 执行命令SQL语句
                sqlCommand.CommandText = "select * from user";
                // 执行命令返回 DataReader
                SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();
                // 输出标题
                Console.WriteLine($"|{"编号",-20}|{"名称",20}|");
                while (sqlDataReader.Read())
                {
                    // 输出行结果
                    Console.WriteLine($"|{sqlDataReader["Code"],-20}|{sqlDataReader["Name"],20}|");
                }
            }
        }
    }
}

using Microsoft.EntityFrameworkCore;
using System.Xml;


namespace Fountain.WinConsole.OtherDemo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            using (var context = new UserDbContext())
            {
                var entity = new UserEntity { Name = "admin" };
                context.UserEntities.Add(entity);
                context.SaveChanges();
            }
        }
    }
    /// <summary>
    /// 用户实体
    /// </summary>
    public class UserEntity
    {
        /// <summary>
        /// 编码
        /// </summary>
        public int Code { get; set; }
        /// <summary>
        /// 名称
        /// </summary>
        public string Name { get; set; }=string.Empty;
    }
    /// <summary>
    /// 
    /// </summary>    
    public class UserDbContext : DbContext
    {
        public DbSet<UserEntity> UserEntities { get; set; }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="options"></param>
        protected override void OnConfiguring(DbContextOptionsBuilder options)
        {
            string connectionString = "Server=127.0.0.1;Database=CRMS;User Id=sa;Password=sa123456;";
            options.UseSqlServer(connectionString);
        }
    }
}

using Dapper;
using System;
using System.Data;
using System.Data.SqlClient;


namespace Fountain.WinConsole.OtherDemo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string connectionString = "Server=127.0.0.1;Database=CRMS;User Id=sa;Password=pwd123456;";
            using (IDbConnection connection = new SqlConnection(connectionString))
            {
                var result = connection.Query<UserEntity>("select * from user");
                foreach (var entity in result)
                {
                    Console.WriteLine($"{entity.Code}, {entity.Name}");
                }
            }
        }
    }
    /// <summary>
    /// 用户实体
    /// </summary>
    public class UserEntity
    {
        /// <summary>
        /// 编码
        /// </summary>
        public int Code { get; set; }
        /// <summary>
        /// 名称
        /// </summary>
        public string Name { get; set; }
    }
}

using SqlSugar;
using System.Data;
using System.Xml;
using static System.Net.Mime.MediaTypeNames;


namespace Fountain.WinConsole.OtherDemo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //数据库链接
            var db = new SqlSugarClient(new ConnectionConfig()
            {
                ConnectionString = "Server=127.0.0.1;Database=CRMS;User Id=sa;Password=sa123456;",
                //指定数据库类型
                DbType = SqlSugar.DbType.SqlServer,
                //链接使用完后是否自动释放
                IsAutoCloseConnection = true,
            });
            // 获取
            UserEntity userEntity= db.Queryable<UserEntity>().First();
            // 输出
            Console.WriteLine($"{userEntity.Code}, {userEntity.Name}");
            // 按任意键推出
            Console.ReadLine();
        }
    }
    /// <summary>
    /// 用户实体
    /// </summary>
    public class UserEntity
    {
        /// <summary>
        /// 编码
        /// </summary>
        public int Code { get; set; }
        /// <summary>
        /// 名称
        /// </summary>
        public string Name { get; set; }=string.Empty;
    }
}