Unable To establish an oracle connection from c# form Application - c#

Im trying to pass two parameters to my oracle package.
I can get the parameters, but it is not being passed into the database. Every time I run the application it fails to make a connection and goes straight to my try catch method.
Is there something I am doing wrong?
This is what I have so far:
using System.Data.OracleClient;
private void btnGetData_Click(object sender, EventArgs e)
{
GetOrders_OracleCon_GetData(Parameter1,Parameter2);
// when i output or add in a break i can see that the data does come into the Parameter values. However after that it doesnt go to my db
}
public void GetOrders_OracleCon_GetData(Int32 PM1, String PM2)
{
using (OracleConnection objConn = new OracleConnection("Data Source=" + dbcon + "; User ID=" + uid + "; Password=" + pass))
{
OracleCommand objCmd = new OracleCommand();
objCmd.Connection = objConn;
objCmd.CommandText = "PCK_Orders.get_data";
objCmd.CommandType = CommandType.StoredProcedure;
objCmd.Parameters.Add("pm1", OracleType.Number).Value = PM1;
objCmd.Parameters.Add("pm2", OracleType.VarChar).Value =PM2;
objCmd.Parameters.Add("selected_orders", OracleType.Cursor).Direction = ParameterDirection.Output;
try
{
objConn.Open();
OracleDataReader objReader = objCmd.ExecuteReader();
if (objReader.HasRows)
{
GetOrders_GetData(objReader);
btnCancel.Enabled = true;
}
else
{
Timer_ProgBar.Stop();
MessageBox.Show("Orders for this Datedoes not exist", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
GP_ClearAllFields("Y", "Y");
Timer_ProgBar_Initialize(0, "");
}
}
catch (Exception)
{
Timer_ProgBar.Stop();
MessageBox.Show("An error has occured");
// this is the error that i catch but im not sure what is causing it. am i missing something?
Timer_ProgBar_Initialize(0, "");
}
objConn.Close();
}
}

Related

How to fix save button

I wrote a code for my pleasure.
i have access data file "mdb" and i show him on gridview from gridview i select row and shown on text box.
i edit the textbox and try to press on Save button and show me error msg.
what i do wrong?
save button didnt save and show me error msg.
add pictures and my code:
Error msg
gridview+textbox
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.OleDb;
namespace Center image description hereDHW
{
public partial class Form2 : Form
{
private OleDbConnection connection = new OleDbConnection();
public Form2()
{
InitializeComponent();
connection.ConnectionString = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source = C:\Users\RBA\Desktop\123\users1.mdb;
Persist Security Info=False;";
}
private void button9_Click(object sender, EventArgs e)
{
this.Close();
Form1 f1 = new Form1();
f1.Show();
}
private void btn_save_Click(object sender, EventArgs e)
{
try
{
connection.Open();
OleDbCommand command = new OleDbCommand();
command.Connection = connection;
command.CommandText = "insert into GRL1 (NoBoard,Site,Group,Kind,Unit) values ('" + txt_noboard.Text + "','" + txt_site.Text + "','" + txt_group.Text + "','" + txt_kind.Text + "','" + txt_unit.Text + "',)";
command.ExecuteNonQuery();
MessageBox.Show("Data Saved");
}
catch (Exception ex)
{
MessageBox.Show("Error " + ex);
}
}
private void Form2_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'users1DataSet.GRL1' table. You can move, or remove it, as needed.
this.gRL1TableAdapter.Fill(this.users1DataSet.GRL1);
}
private void btn_loadGR_Click(object sender, EventArgs e)
{
try
{
connection.Open();
OleDbCommand command = new OleDbCommand();
command.Connection = connection;
string query = "select * from GRL1";
command.CommandText = query;
OleDbDataAdapter da = new OleDbDataAdapter(command);
DataTable dt = new DataTable();
da.Fill(dt);
dataGridView1.DataSource = dt;
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error " + ex);
}
}
private void button3_Click(object sender, EventArgs e)
{
try
{
connection.Open();
OleDbCommand command = new OleDbCommand();
command.Connection = connection;
string query = "select * from GRS1";
command.CommandText = query;
OleDbDataAdapter da = new OleDbDataAdapter(command);
DataTable dt = new DataTable();
da.Fill(dt);
dataGridView1.DataSource = dt;
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error " + ex);
}
}
private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
if (e.RowIndex >= 0)
{
DataGridViewRow row = this.dataGridView1.Rows[e.RowIndex];
txt_noboard.Text = row.Cells[0].Value.ToString();
txt_site.Text = row.Cells[1].Value.ToString();
txt_group.Text = row.Cells[2].Value.ToString();
txt_kind.Text = row.Cells[3].Value.ToString();
txt_unit.Text = row.Cells[4].Value.ToString();
txt_com.Text = row.Cells[5].Value.ToString();
}
}
}
}

You have a typo in your sql text. There is a comma before the close brace. But there is also an error caused by the usage of a reserved keyword in MS-Access (Group). You need to put square brackets around that name.
Finally, do not use string concatenation to build sql commands but always use parameters.
This avoid sql injection hacks and remove problem with parsing your inputs (for example if there is a single quote in your input text the whole query will fail again with a syntax error)
private void btn_save_Click(object sender, EventArgs e)
{
try
{
using(OleDbConnection connection = new OleDbConnection(....con string...))
{
connection.Open();
OleDbCommand command = new OleDbCommand();
command.Connection = connection;
// Notice how Group field is between square brackets.
// If you can I suggest to change the name of this field
string cmdText = #"insert into GRL1 (NoBoard,Site,[Group],Kind,Unit)
values (#nob, #sit, #grp, #knd, #uni)";
command.CommandText = cmdText;
// Is NoBoard an integer? If yes you should pass an integer not a string
command.Parameters.Add("#nob", OleDbType.Integer).Value = Convert.ToInt32(txt_noboard.Text);
command.Parameters.Add("#sit", OleDbType.VarWChar).Value = txt_site.Text;
command.Parameters.Add("#grp", OleDbType.VarWChar).Value = txt_group.Text;
command.Parameters.Add("#knd", OleDbType.VarWChar).Value = txt_kind.Text;
command.Parameters.Add("#uni", OleDbType.VarWChar).Value = txt_unit.Text;
command.ExecuteNonQuery();
MessageBox.Show("Data Saved");
}
}
catch (Exception ex)
{
MessageBox.Show("Error " + ex);
}
}
The parameters collection is filled with the values required by your query text. Notice that I don't know exactly the datatype of your columns in the database. The parameter OleDbType should exactly match the types expected to avoid Type Mismatch exceptions
Last tip. Connections should be created, opened and closed when needed. Do not keep a global connection object. You don't get much gain in performance because ADO.NET employs a technique called Connection Pooling

C# Syntax Error in INSERT INTO statement C#

if (txtUsername.Text != "")
{
string q = "insert into info(Username) values ('" + txtUsername.Text.ToString() + "')";
dosomething(q);
txtUsername.Text = "";
}
else
{
MessageBox.Show("Please Complete the neccessary information");
}
if (txtPassword.Text != "")
{
string a = "insert into info(Password) values ('" + txtPassword.Text.ToString() + "')";
dosomething(a);
txtUsername.Text = "";
}
else
{
MessageBox.Show("Please Complete the neccessary information");
}
private void dosomething(String q)
{
try
{
cn.Open();
cmd.CommandText = q;
cmd.ExecuteNonQuery();
cn.Close();
}
catch (Exception e)
{
cn.Close();
MessageBox.Show(e.Message.ToString());
}
}
Every time I run this it always show that error. I dont know how to fix it.
The code should record the data i put in a textbox to ms access database. plz helpp

Presumably, you've initialized cn somewhere by doing something like
cn = new SqlConnection();
You need to pass the connection string for the database to the constructor:
cn = new SqlConnection("your connection string here");
or set it sometime later, before you connect:
cn.ConnectionString = "your connection string here";

create a login page in vb.net by c# & mysql but it shows error message connection must be valid and open

private void admin_submit_button_Click(object sender, EventArgs e)
{
try
{
string myConnection = "datasource= localhost;port=3306;username=root;password=root";
MySqlConnection myConn = new MySqlConnection(myConnection);
MySqlCommand SelectCommand = new MySqlCommand("select * from mws.login_info where login_id='" + this.admin_id_textbox + "'and login_password1='" + this.admin_password_textbox1 + "' and login_password2='" + this.admin_password_textbox2 + "'");
MySqlDataReader myReader;
myConn.Open();
myReader = SelectCommand.ExecuteReader();
int count = 0;
while (myReader.Read())
{
count = count + 1;
}
if (count == 1)
{
MessageBox.Show("username and password is correct");
}
else
MessageBox.Show("username and password not correct");
myConn.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}

You have not associated the command with the connection. You code lacks of the following line
SelectCommand.Connection = myConn ;
Said that, imagine that I write in your admin_id_textbox the following text
' OR login_id like '%' --
what happen to your checks for the correct login?
It is called Sql Injection and it is a very dangerous situation for every kind of database access.
Use always a parameterized query to build sql commands, in particular when part of your command is built using user input text
private void admin_submit_button_Click(object sender, EventArgs e)
{
try
{
string cmdText = #"select * from mws.login_info
where login_id=#id and login_password1=#pwd
and login_password2=#pwd2";
string myConnection = "datasource= localhost;port=3306;username=root;password=root";
using(MySqlConnection myConn = new MySqlConnection(myConnection))
using(MySqlCommand SelectCommand = new MySqlCommand(cmdText, myConnection))
{
myConn.Open();
SelectCommand.Parameters.AddWithValue("#id", this.admin_id_textbox);
SelectCommand.Parameters.AddWithValue("#pwd",this.admin_password_textbox1);
SelectCommand.Parameters.AddWithValue("#pwd2",this.admin_password_textbox2);
using(MySqlDataReader myReader = SelectCommand.ExecuteReader())
{
if(myReader.HasRows)
MessageBox.Show("username and password is correct");
else
MessageBox.Show("username and password not correct");
}
}
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}

SQL Insert Query Using C#

I'm having an issue at the moment which I am trying to fix. I just tried to access a database and insert some values with the help of C#
The things I tried (worked)
String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES ('abc', 'abc', 'abc', 'abc')";
A new line was inserted and everything worked fine, now I tried to insert a row using variables:
String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (#id, #username, #password, #email)";
command.Parameters.AddWithValue("#id","abc")
command.Parameters.AddWithValue("#username","abc")
command.Parameters.AddWithValue("#password","abc")
command.Parameters.AddWithValue("#email","abc")
command.ExecuteNonQuery();
Didn't work, no values were inserted. I tried one more thing
command.Parameters.AddWithValue("#id", SqlDbType.NChar);
command.Parameters["#id"].Value = "abc";
command.Parameters.AddWithValue("#username", SqlDbType.NChar);
command.Parameters["#username"].Value = "abc";
command.Parameters.AddWithValue("#password", SqlDbType.NChar);
command.Parameters["#password"].Value = "abc";
command.Parameters.AddWithValue("#email", SqlDbType.NChar);
command.Parameters["#email"].Value = "abc";
command.ExecuteNonQuery();
May anyone tell me what I am doing wrong?
Kind regards
EDIT:
in one other line I was creating a new SQL-Command
var cmd = new SqlCommand(query, connection);
Still not working and I can't find anything wrong in the code above.

I assume you have a connection to your database and you can not do the insert parameters using c #.
You are not adding the parameters in your query. It should look like:
String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (#id,#username,#password, #email)";
SqlCommand command = new SqlCommand(query, db.Connection);
command.Parameters.Add("#id","abc");
command.Parameters.Add("#username","abc");
command.Parameters.Add("#password","abc");
command.Parameters.Add("#email","abc");
command.ExecuteNonQuery();
Updated:
using(SqlConnection connection = new SqlConnection(_connectionString))
{
String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (#id,#username,#password, #email)";
using(SqlCommand command = new SqlCommand(query, connection))
{
command.Parameters.AddWithValue("#id", "abc");
command.Parameters.AddWithValue("#username", "abc");
command.Parameters.AddWithValue("#password", "abc");
command.Parameters.AddWithValue("#email", "abc");
connection.Open();
int result = command.ExecuteNonQuery();
// Check Error
if(result < 0)
Console.WriteLine("Error inserting data into Database!");
}
}

Try
String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (#id,#username, #password, #email)";
using(SqlConnection connection = new SqlConnection(connectionString))
using(SqlCommand command = new SqlCommand(query, connection))
{
//a shorter syntax to adding parameters
command.Parameters.Add("#id", SqlDbType.NChar).Value = "abc";
command.Parameters.Add("#username", SqlDbType.NChar).Value = "abc";
//a longer syntax for adding parameters
command.Parameters.Add("#password", SqlDbType.NChar).Value = "abc";
command.Parameters.Add("#email", SqlDbType.NChar).Value = "abc";
//make sure you open and close(after executing) the connection
connection.Open();
command.ExecuteNonQuery();
}

The most common mistake (especially when using express) to the "my insert didn't happen" is : looking in the wrong file.
If you are using file-based express (rather than strongly attached), then the file in your project folder (say, c:\dev\myproject\mydb.mbd) is not the file that is used in your program. When you build, that file is copied - for example to c:\dev\myproject\bin\debug\mydb.mbd; your program executes in the context of c:\dev\myproject\bin\debug\, and so it is here that you need to look to see if the edit actually happened. To check for sure: query for the data inside the application (after inserting it).

static SqlConnection myConnection;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
myConnection = new SqlConnection("server=localhost;" +
"Trusted_Connection=true;" +
"database=zxc; " +
"connection timeout=30");
try
{
myConnection.Open();
label1.Text = "connect successful";
}
catch (SqlException ex)
{
label1.Text = "connect fail";
MessageBox.Show(ex.Message);
}
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
String st = "INSERT INTO supplier(supplier_id, supplier_name)VALUES(" + textBox1.Text + ", " + textBox2.Text + ")";
SqlCommand sqlcom = new SqlCommand(st, myConnection);
try
{
sqlcom.ExecuteNonQuery();
MessageBox.Show("insert successful");
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message);
}
}

private void button1_Click(object sender, EventArgs e)
{
String query = "INSERT INTO product (productid, productname,productdesc,productqty) VALUES (#txtitemid,#txtitemname,#txtitemdesc,#txtitemqty)";
try
{
using (SqlCommand command = new SqlCommand(query, con))
{
command.Parameters.AddWithValue("#txtitemid", txtitemid.Text);
command.Parameters.AddWithValue("#txtitemname", txtitemname.Text);
command.Parameters.AddWithValue("#txtitemdesc", txtitemdesc.Text);
command.Parameters.AddWithValue("#txtitemqty", txtitemqty.Text);
con.Open();
int result = command.ExecuteNonQuery();
// Check Error
if (result < 0)
MessageBox.Show("Error");
MessageBox.Show("Record...!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
con.Close();
loader();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
con.Close();
}
}

public static string textDataSource = "Data Source=localhost;Initial
Catalog=TEST_C;User ID=sa;Password=P#ssw0rd";
public static bool ExtSql(string sql) {
SqlConnection cnn;
SqlCommand cmd;
cnn = new SqlConnection(textDataSource);
cmd = new SqlCommand(sql, cnn);
try {
cnn.Open();
cmd.ExecuteNonQuery();
cnn.Close();
return true;
}
catch (Exception) {
return false;
}
finally {
cmd.Dispose();
cnn = null;
cmd = null;
}
}

I have just wrote a reusable method for that, there is no answer here with reusable method so why not to share...here is the code from my current project:
public static int ParametersCommand(string query,List<SqlParameter> parameters)
{
SqlConnection connection = new SqlConnection(ConnectionString);
try
{
using (SqlCommand cmd = new SqlCommand(query, connection))
{ // for cases where no parameters needed
if (parameters != null)
{
cmd.Parameters.AddRange(parameters.ToArray());
}
connection.Open();
int result = cmd.ExecuteNonQuery();
return result;
}
}
catch (Exception ex)
{
AddEventToEventLogTable("ERROR in DAL.DataBase.ParametersCommand() method: " + ex.Message, 1);
return 0;
throw;
}
finally
{
CloseConnection(ref connection);
}
}
private static void CloseConnection(ref SqlConnection conn)
{
if (conn.State != ConnectionState.Closed)
{
conn.Close();
conn.Dispose();
}
}

class Program
{
static void Main(string[] args)
{
string connetionString = null;
SqlConnection connection;
SqlCommand command;
string sql = null;
connetionString = "Data Source=Server Name;Initial Catalog=DataBaseName;User ID=UserID;Password=Password";
sql = "INSERT INTO LoanRequest(idLoanRequest,RequestDate,Pickupdate,ReturnDate,EventDescription,LocationOfEvent,ApprovalComments,Quantity,Approved,EquipmentAvailable,ModifyRequest,Equipment,Requester)VALUES('5','2016-1-1','2016-2-2','2016-3-3','DescP','Loca1','Appcoment','2','true','true','true','4','5')";
connection = new SqlConnection(connetionString);
try
{
connection.Open();
Console.WriteLine(" Connection Opened ");
command = new SqlCommand(sql, connection);
SqlDataReader dr1 = command.ExecuteReader();
connection.Close();
}
catch (Exception ex)
{
Console.WriteLine("Can not open connection ! ");
}
}
}

Update Query problem in asp.net c# and Mysql using odbc

when i specify values in my update query the query works fine and the database gets updated, but when i use parameters in my query the database does not update
here is the code i have written
try
{
OdbcConnection MyConnection = new OdbcConnection(ConfigurationManager.ConnectionStrings["myconn"].ConnectionString);
MyConnection.Open();
String MyString = "UPDATE orddetpabak SET jud1=#jud1,jud2=#jud2,jud3=#jud3,adv=#adv where fil_no=#fil_no AND orderdate=#orderdate";
OdbcCommand MyCmd = new OdbcCommand(MyString, MyConnection);
String j1=DropDownList4.SelectedValue;
String j2=DropDownList5.SelectedValue;
String j3=DropDownList6.SelectedValue;
String j4=TextBox4.Text;
String j5 = HiddenField1.Value;
String j6 = TextBox3.Text;
MyCmd.Parameters.AddWithValue("#jud1",j1);
MyCmd.Parameters.AddWithValue("#jud2",j2);
MyCmd.Parameters.AddWithValue("#jud3",j3);
MyCmd.Parameters.AddWithValue("#adv",j4);
MyCmd.Parameters.AddWithValue("#fil_no",j5);
MyCmd.Parameters.AddWithValue("#orderdate",j6);
Response.Write(DropDownList4.SelectedValue);
Response.Write(" " + DropDownList5.SelectedValue);
Response.Write(" " + DropDownList6.SelectedValue);
Response.Write(" " + TextBox4.Text);
Response.Write(" " + HiddenField1.Value);
Response.Write(" " + TextBox3.Text);
MyCmd.ExecuteNonQuery();
//MyConnection.Close();
}
catch(Exception epp)
{
Response.Write(epp);
}
Please Help

As far as I know you cannot use named parameters in MySQL. If you change your string to be
String MyString = "UPDATE orddetpabak SET jud1=?,jud2=?,jud3=?,adv=?
where fil_no=? AND orderdate=?";
and your parameters as:
MyCmd.Parameters.AddWithValue("",j1);
MyCmd.Parameters.AddWithValue("",j2);
MyCmd.Parameters.AddWithValue("",j3);
MyCmd.Parameters.AddWithValue("",j4);
MyCmd.Parameters.AddWithValue("",j5);
MyCmd.Parameters.AddWithValue("",j6);
Hope this helps.

It can be like the following: (I'm using the ADO.NET driver for MySQL version 6.3.7.0, latest one had some issues).
public bool UpdateCustomerIAR(IAR oIAR)
{
bool bRetVal = false;
try
{
MySqlConnection dbConnection = new MySqlConnection(APPSConn.ConnectionString);
MySqlCommand dbCommand = dbConnection.CreateCommand();
string szSQL = string.Empty;
szSQL = "UPDATE schema.table_name SET field_name_one=?field_name_one";
szSQL += " WHERE field_name_two=?field_name_two";
using (MySql.Data.MySqlClient.MySqlConnection conn = new
MySql.Data.MySqlClient.MySqlConnection(APPSConn.ConnectionString))
{
MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
cmd.Connection = conn;
cmd.CommandText = szSQL;
cmd.Parameters.AddWithValue("?field_name_one", oIAR.Title);
cmd.Parameters.AddWithValue("?field_name_two", oIAR.IARID.ToString());
conn.Open();
cmd.ExecuteNonQuery();
bRetVal = true;
}
return bRetVal;
}
catch (MySqlException ex)
{
ErrorHandler(ex.ToString());
return bRetVal;
}
catch (Exception ex)
{
ErrorHandler(ex.ToString());
return bRetVal;
}
}

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