Developer Help BLOG

using System;
using System.Collections.Generic;
using System.Text;

namespace Math1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Math메소드로 소수점 처리 방법");
            decimal pf = Math.Floor(1.7m);
            Console.WriteLine(pf);

            decimal pc = Math.Ceiling(1.7m);
            Console.WriteLine(pc);
        }
    }
} 

namespace Math2
{
    class Program
    {
        static void Main(string[] args)
        {
            decimal v = 1.34m;

            v *= 10;
            Console.WriteLine("1.34m *= 10 = {0}", v);

            v = Math.Floor(v);
            v /= 10;
            Console.WriteLine("Result = {0}", v);
        }
    }
} 

1. ///Get the sub-domain from the provided URL
2. /// </summary>
3. /// <param name="url">URL to retrieve sub-domain from</param>
4. /// <returns></returns>
5. public static string RetrieveSubDomain(Uri url)
6. {
7.     string subDomain = "";
8.     if (url.HostNameType == UriHostNameType.Dns && (!(url.HostNameType == UriHostNameType.Unknown)))
9.     {
10.         string host = url.Host;
11.         int length = host.Split('.').Length;
12.         if (length > 2)
13.         {
14.             int last = host.LastIndexOf(".");
15.             int idx = host.LastIndexOf(".", last - 1);
16.             subDomain = host.Substring(0, idx);
17.         }
18.     }
19.  
20.     return subDomain;
21. }
    
    
    

///Get the sub-domain from the provided URL
/// </summary>
/// <param name="url">URL to retrieve sub-domain from</param>
/// <returns></returns>
public static string RetrieveSubDomain(Uri url)
{
    string subDomain = "";
    if (url.HostNameType == UriHostNameType.Dns && (!(url.HostNameType == UriHostNameType.Unknown)))
    {
        string host = url.Host;
        int length = host.Split('.').Length;
        if (length > 2)
        {
            int last = host.LastIndexOf(".");
            int idx = host.LastIndexOf(".", last - 1);
            subDomain = host.Substring(0, idx);
        }
    }

    return subDomain;
}

            connection.ConnectionString = connectionString;

            try
            {

                string commandStirng = "select * from test";

                MySqlDataAdapter DBAdapter = new MySqlDataAdapter(commandStirng, connection);
                DataSet DS = new DataSet();
                DBAdapter.Fill(DS, "test");

                dataGridView1.DataSource = DS.Tables["test"].DefaultView;
                //MessageBox.Show("연결됨");

            }
            catch (Exception E)
            {
                MessageBox.Show(E.ToString());
            }
            finally
            {
                connection.Close();
            }
}

기본 골격이고 신경써야 할 부분은 형광색 부분입니다.
1. 127.0.0.1 : Mysql이 설치된 원격지의 데이터베이스 IP어드레스 입니다.
2. MY_DB : 사용할 데이터베이스명
3. MY_ID : 데이터베이스 사용 ID
4. MY_PW : 데이터베이스 사용 PASSWORD
5. select * from test : 데이터베이스에 질의할 쿼리(본 예제는 Select로만 응용가능합니다)
예) select * from test where field1 = 1;
     select * from test order by field2 desc;
6. test : DBAdapter와 DS.Tables에 쿼리에 질의한 테이블 명을 적어 줍니다.
예) select * from angpang; //테이블 명이 angpang 입니다.
    .............................
    string commandStirng = "select * from angpang";

                MySqlDataAdapter DBAdapter = new MySqlDataAdapter(commandStirng,         connection);
                DataSet DS = new DataSet();
                DBAdapter.Fill(DS, "angpang");

                dataGridView1.DataSource = DS.Tables["angpang"].DefaultView;
                //MessageBox.Show("연결됨");
    .............................

7. dataGridView1 : 주로 결과값은 데이터그리드 뷰 컨트롤과 많이 사용합니다. 데이터그리드 뷰를 추가하여 Name 속성을 맞춰주면 결과값이 보여질 것입니다.

시간나면 Update 쿼리 응용법, Insert 쿼리 응용법, 데이터그리드뷰를 효율적으로 쓰는방법,
데이터베이스에 이미지를 2진코드로 저장하여 활용하는법 등을 기술해 보겠습니다.
감사합니다 ^^

간단한 C# 디비연결....ㅎㅎㅎㅎ

ADO.NET
     Contents

Object Model
　
기본  Data Access
C#

- 연결 설정
　
using System.Data;
using System.Data.SqlClient;
 // ...
public void Openning()
{

string ConnectionString = "server=localhost;database=dbTest;uid=sa;pwd=sa";
SqlConnection Connect = new SqlConnection(ConnectionString);
Connect.Open();
Connect.Close();

}　

- Update　
// ExecuteNonQuery
public void Updating()
{

string ConnectionString = "server=localhost;database=dbTest;uid=sa;pwd=sa";
SqlConnection Connect = new SqlConnection(ConnectionString);
string strInsertSQL = "Insert Into tblTest( Id, col2) Values(1,11)";
SqlCommand Command = new SqlCommand(strInsertSQL, Connect);
Connect.Open();
Command.ExecuteNonQuery();
Connect.Close();

}
　

- Query 1　
// ExecuteScalar

public void Quering1()

{

string ConnectionString = "server=localhost;database=dbTest;uid=sa;pwd=sa";
SqlConnection Connect = new SqlConnection(ConnectionString);
string strSelectSQL = "Select count(tblTest.Id) From tblTest";
SqlCommand Command = new SqlCommand(strSelectSQL, Connect);
Connect.Open();
int count = (int)Command.ExecuteScalar();
Connect.Close();
// ...

}

- Query 2　
// ExecuteReader // forward-only stream
public void Quering2()
{

string ConnectionString = "server=localhost;database=dbTest;uid=sa;pwd=sa";
SqlConnection Connect = new SqlConnection(ConnectionString);
string strSelectSQL = "Select tblTest.Id, tblTest.col2 From tblTest";
SqlCommand Command = new SqlCommand(strSelectSQL, Connect);
Connect.Open();
SqlDataReader Reader= Command.ExecuteReader();// forward-only stream

while(Reader.Read())
{

string strId = Reader["Id"].ToString();
string strcol2 = Reader["col2"].ToString();
Console.WriteLine("{0}:{1}", strId, strcol2);

}

Connect.Close();

}

- 예외 처리　

- 기타　

DataSet 과 DataAdapter
- 비 연결성 Data 조작 제공

- Query 3　
// SqlDataAdapter  &  DataSet

public void Quering3()

{

 string ConnectionString = "server=localhost;database=dbTest;uid=sa;pwd=sa";
 SqlConnection Connect = new SqlConnection(ConnectionString);
 string strSelectSQL = "Select tblTest.Id, tblTest.col2 From tblTest";
 SqlCommand Command = new SqlCommand(strSelectSQL, Connect);
 DataSet ds = new DataSet();
 SqlDataAdapter aDataAdapter = new SqlDataAdapter(strSelectSQL,Connect);
 Connect.Open();
 aDataAdapter.Fill(ds);
 Connect.Close();

 foreach(DataTable aTable in ds.Tables)
 {
  foreach(DataRow aRow in aTable.Rows)
  {
   string strId = aRow["Id"].ToString().Trim();
   string strcol2 = aRow["col2"].ToString().Trim();
   Console.WriteLine("{0}:{1}", strId, strcol2);
  }
 }
}