C# 数据库的操作

一：数据库连接代码： 
SqlConnection objSqlConnection = new SqlConnection ("server = 127.0.0.1;uid = sa; pwd =;database =test"); 
objSqlConnection.Open(); 
二：数据库的添加记录代码：             int i = 0; 
          string s1 = "", s2 = ""; 
          i = Convert.ToInt16(textBox1.Text);               s1 = textBox2.Text;           s2 = textBox3.Text; 
            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test"); 
            objSqlConnection.Open();              
            MessageBox.Show("数据库连接成功", "好");                try                { 
                  SqlCommand sqlcom = new SqlCommand("insert into info(id,name,sex) values( " + i + ",'" + s1 + "','" + s2 + "')", objSqlConnection);                   sqlcom.ExecuteNonQuery(); 
                   MessageBox.Show("添加成功！", "啊");                } 
              catch (Exception a)                { 
                   MessageBox.Show(a.ToString());                } 
            MessageBox.Show("添加成功！", "啊"); }  
三：数据库的修改代码：             int i = 0; 
            string s1 = "", s2 = "";             s1 = textBox2.Text;             s2 = textBox3.Text; 
            if (textBox1.Text.Length == 0)                 i = 0;             else 
                i = Convert.ToInt32(textBox1.Text); 
            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test"); 

 
 
            objSqlConnection.Open(); 
            MessageBox.Show("数据库连接成功", "好");             try             { 
                SqlCommand 
sqlcom = new SqlCommand("update info set 
name='"+s1+"',sex='"+s2+"'"+"where id=" + i, objSqlConnection);                 sqlcom.ExecuteNonQuery(); 
                MessageBox.Show("修改成功！", "啊");                 objSqlConnection.Close();             } 
            catch (Exception a)             { 
                MessageBox.Show(a.ToString());             } 
四：数据库的删除代码：             int i = 0; 
            string s1 = "", s2 = "";             s1 = textBox2.Text;             s2 = textBox3.Text;             if(textBox1.Text.Length==0)                 i=0; 
            else 
                 i = Convert.ToInt16(textBox1.Text); 
            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");             
            objSqlConnection.Open(); 
            MessageBox.Show("数据库连接成功", "好"); 
            try             { 
                SqlCommand sqlcom = new SqlCommand("delete from info where id="+i, objSqlConnection); 
                sqlcom.ExecuteNonQuery(); 
                MessageBox.Show("删除成功！", "啊");                 objSqlConnection.Close();             } 
            catch (Exception a)             { 
                MessageBox.Show(a.ToString());             } 
五：数据库的查询代码：             1.类开始： 
                  DataTable dt1 = new DataTable(); 
                  SqlDataAdapter da1 = new SqlDataAdapter();             2.按钮代码： 

 
 
            int i = 0,n=0; 
            string s1 = "", s2 = "";             s1 = textBox2.Text;             s2 = textBox3.Text; 
           if (textBox1.Text.Length == 0)                 i = 0;             else 
                i = Convert.ToInt32(textBox1.Text); 
            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test"); 
            objSqlConnection.Open(); 
            MessageBox.Show("数据库连接成功", "好");             string query = "SELECT * from info where id="+i;             DataSet objDataSet = new DataSet(); 
            SqlDataAdapter obj = new SqlDataAdapter();            
            obj.SelectCommand = new SqlCommand(query, objSqlConnection);             obj.Fill(objDataSet, "info");         
            SqlCommand objSqlCommand = new SqlCommand(query, objSqlConnection);             SqlDataReader objSqlReader = objSqlCommand.ExecuteReader();              while (objSqlReader.Read()) 
                { 
                    n += 1; 
                    MessageBox.Show("编号: " + objSqlReader.Getvalue(0) + "  姓名:" + objSqlReader.Getvalue(1) + "  性别" + objSqlReader.Getvalue(2));                 } 
                if (n == 0) 
                    MessageBox.Show("数据库中没有这样的记录！"); 六：数据库的查询代码：        int i = 0; 
           // int n = 0; 
            string s1 = "", s2 = "";             string sql; 
            s1 = textBox2.Text; 
            s2 = textBox3.Text; 
            if (textBox1.Text.Length == 0)             {                 i = 0;                              }             else 
                i = Convert.ToInt32(textBox1.Text); 
           SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");           

 
 
            objSqlConnection.Open(); 
            MessageBox.Show("数据库连接成功", "好");             string query = "SELECT * from info where id="+i;             if(i==0) 
                  sql = "select * from info ";             else 
                  sql = "select * from info where id=" + i;             da1 = new SqlDataAdapter(sql, objSqlConnection);  
            dt1.Clear(); 
            da1.Fill(dt1); 
            dataGridView1.DataSource = dt1;  
数据库的封装类代码： class DBClass     { 
        public void dbclass(string  sql)         {             try             { 
                SqlConnection sqlcon = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test"); 
                sqlcon.Open();              
                SqlTransaction objt = sqlcon.BeginTransaction();  //事物开始                
                SqlCommand sqlcom = new SqlCommand(sql, sqlcon); 
                 
                sqlcom.Transaction = objt; //将Command 对象设置为事物处理的对象              
                sqlcom.ExecuteNonQuery();                 objt.Commit();         //提交事物                 sqlcon.Close();             } 
            catch (Exception a)             { 
                MessageBox.Show(a.ToString());             }                    }     } 
   
--db2 数据库连接代码：    
string strcon = "Provider = IBMDADB2; Data Source=hfzd;User 

 
 
Id=db2admin;Password=db2admin"; 
            //string sql = "select * from ADMINISTRATOR.HFZD";            
            string sql = "delete from ADMINISTRATOR.HFZD where ID=1";             OleDbConnection olecon = new OleDbConnection(strcon);             olecon.Open(); 
            MessageBox.Show("数据库已连接上");              dt.Clear(); 
            da = new OleDbDataAdapter(sql, olecon);             da.Fill(dt); 
            dataGridView1.DataSource = dt;             olecon.Close();