backup: sqlHelper --cSharp

用在只有一两个表操作也极为简单的小玩具里。

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Text;

namespace Simple.SqlHelpers
{
    internal class SqlHelper
    {

        /// <summary>
        /// 数据库连接字符串
        /// </summary>
        internal string ConnectionString { get; set; } 


        public SqlHelper()
        {
        }

        
        internal List<T> Query<T>(string sql, Func<SqlDataReader, T> convert, params SqlParameter[] sqlParams)
        {
            List<T> result = new List<T>();

            using (var conn = new SqlConnection(ConnectionString))
            {
                using (var command = new SqlCommand(sql, conn))
                {
                    command.Parameters.AddRange(sqlParams);

                    conn.Open();
                    using (var reader = command.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            result.Add(convert(reader));
                        }
                    }
                }
            }
            return result;
        }

        internal void Update(string sql, params SqlParameter[] sqlParams)
        {
            using (var conn = new SqlConnection(ConnectionString))
            {
                using (var command = new SqlCommand(sql, conn))
                {
                    command.Parameters.AddRange(sqlParams);

                    conn.Open();
                    command.ExecuteNonQuery();
                }
            }
        }

        internal void ActionUpdate(Action<SqlConnection> action)
        {
            using (var conn = new SqlConnection(ConnectionString))
            {
                action(conn);
            }
        }

    } // class
}

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Simple.SqlHelpers
{
    internal class SqlDataReaderUtil
    {
        public static string ReadString(SqlDataReader reader, string name, string defaultVal)
        {
            int ordinal = reader.GetOrdinal(name);
            return reader.IsDBNull(ordinal)
                ? defaultVal
                : reader.GetValue(ordinal).ToString();
        }

        public static int ReadInt(SqlDataReader reader, string name, int defaultVal)
        {
            int ordinal = reader.GetOrdinal(name);
            if (reader.IsDBNull(ordinal))
            {
                return defaultVal;
            }

            return Convert.ToInt32(reader.GetValue(ordinal));
        }

        public static long ReadLong(SqlDataReader reader, string name, long defaultVal)
        {
            int ordinal = reader.GetOrdinal(name);
            if (reader.IsDBNull(ordinal))
            {
                return defaultVal;
            }

            return Convert.ToInt64(reader.GetValue(ordinal));
        }

        public static double ReadDouble(SqlDataReader reader, string name, double defaultVal)
        {
            int ordinal = reader.GetOrdinal(name);
            if (reader.IsDBNull(ordinal))
            {
                return defaultVal;
            }

            return Convert.ToDouble(reader.GetValue(ordinal));
        }


    }
}

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