C#中oracle数据库的连接方法

C#中oracle数据库的连接方法

一、关于数据库的操作
1.数据库连接
     有2种:
     第一种:古老的方法(较为死板,不利于灵活操作),即用OracleConnection的类来连接
             string
mysqlstr ="user id = xal;data source = xal;password = xal";
            
OracleConnection mycnn = new OracleConnection(mysqlstr);
            
mycnn.open();
     第二种:新式的方法(使用较为灵活),即利用OracleConnectoinStringBuilder类来连接
            
OracleConnectionStringBuilder OcnnStrB = new OracleConnectionStringBuilder;
            
OCnnStrB.DataSource = "xal";
            
OCnnStrB.UserID = "xal";
            
OCnnStrB.Password = "xal";
             myCnn
= new OracleConnection(OCnnStrB.ConnectionString);
            
myCnn.open();

2.事务操作
 myConn.open();
      OracleCommand insertComm = new OracleCommand();
               
insertComm.Connection = myCnn;
               
insertComm.Transaction = myCnn.BeginTransaction();
 try
     {
  事务操作语句;
   insertComm.Transaction.Commit();
     }
 catch(exption ex)
     {
  insertComm.Transaction.Rollback();
  MessageBox(ex.Message);
     }
 finally
     {
  myConn.close();
     }

3.创建命令参数
        private OracleParameter
CreateOraParam(string ParamName, object ParamValue)
        {
           
OracleParameter Result = new OracleParameter();
           
Result.ParameterName = ParamName;
            if
(ParamValue != null)
            {
               
Result.Value = ParamValue;
            }
            else
            {
               
Result.Value = DBNull.Value;
            }
            return
Result;
        }
       这样的话,当要对数据库操作时就可以:
            
insertComm.CommandText = "insert into TESTADODOTNET (ID, NAME, AGE, PIC)
values (:pID, :pName, :pAge, :pPic)";
            
insertComm.Parameters.Add(CreateOraParam("pID", (txtID.Text.Trim() !=
"") ? txtID.Text.Trim() : null));
            
insertComm.Parameters.Add(CreateOraParam("pName",
(txtName.Text.Trim() != "") ? txtName.Text.Trim() : null));
            
insertComm.Parameters.Add(CreateOraParam("pAge", (txtAge.Text.Trim()
!= "") ? txtAge.Text.Trim() : null));

4.数据集的浏览(例:将结果显示在comboBox1中)
             
OracleDataAdapter oda = new OracleDataAdapter(selectCommand);
             
DataTable newtable = new DataTable();
             
oda.Fill(newtable);
       foreach (DataRow dr in
newtable.Rows)  //共有newtable.rows.count条记录
               
{
      comboBox1.Items.Add(dr[0].ToString());
      }

5.设置输入只能是数字(例:现在往textBox1中输入。如只能输入字母的方法类似)
 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)//属性中的事件
         {
           
      e.Handled = !((Char.IsNumber(e.KeyChar)) ||
((Keys)e.KeyChar == Keys.Back));
         }

6.Form窗口关闭时引发的事件:弹出一个确定退出的对话框
  private void form1_FormClosing(object sender, FormClosingEventArgs
e)
         {
          if
(MessageBox.Show("是否退出系统?", "确认", MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
DialogResult.Yes)
            {
                 
e.Cancel = false;
            }
          else
            {
              
   e.Cancel = true;
            }
        }

7.OracleParameter的用法
        第一步:先创建命令参数
        private OracleParameter CreateOraParam(string
ParamName, object ParamValue)
        {
           
OracleParameter Result = new OracleParameter();
           
Result.ParameterName = ParamName;
            if
(ParamValue != null)
            {
               
Result.Value = ParamValue;
            }
            else
            {
               
Result.Value = DBNull.Value;
            }
            return
Result;
        }
       第二步:写SQL语句,并调用第一步的参数(例如::pID是个参数,代表调用insertComm.Parameters.Add中的pID的值)
        insertComm.CommandText = "insert
into TESTADODOTNET (ID, NAME, AGE, PIC) values (:pID, :pName, :pAge,
:pPic)";
 insertComm.Parameters.Add(CreateOraParam("pID",
(txtID.Text.Trim() != "") ? txtID.Text.Trim() : null));
       
insertComm.Parameters.Add(CreateOraParam("pName", (txtName.Text.Trim()
!= "") ? txtName.Text.Trim() : null));
       
insertComm.Parameters.Add(CreateOraParam("pAge", (txtAge.Text.Trim()
!= "") ? txtAge.Text.Trim() : null));

第三步:添加pictureBox1图片的二进制流字段pAge
                
//创建字节数组用于给IMAGE字段赋值,fileLength是指所选的文件的大小
         byte[] tmpImage = new
byte[fileLength];
               
//根据字节数组创建内存流,之后对该流的操作将会影响字节数组的内容
         MemoryStream curStream = new
MemoryStream(tmpImage);
                
//把控件内显示的图形写入到流中,需强制指定格式
        
pictureBox1.Image.Save(curStream, curImageFormat);//curImageFormat前面指定的图片格式
        
insertComm.Parameters.Add(CreateOraParam("pPic", tmpImage));

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