Develop Reference

The type or namespace name 'OleDbConnection' could not be found (are you missing a using directive or an assembly reference?)

I am trying to parse from excel format to json.Below is the tried code I am getting problem with "OleDbConnection". I tried different solutions but nothing seems to work.
using System;
using System.Linq;
using System.Data;
using System.Data.OleDb;
using System.Data.Common;
using Newtonsoft.Json;
using System.IO;
namespace ResumeParsing
{
class Program
{
static void Main(string[] args)
{
var pathToExcel = #"C:\Users\Admin\Desktop\resumeexcelformat.xlsx";
var sheetName = "Sheet1";
var destinationPath = #"C:\path\to\save\json\file.json";
//Use this connection string if you have Office 2007+ drivers installed and
//your data is saved in a .xlsx file
var connectionString = $#"
Provider=Microsoft.ACE.OLEDB.12.0;
Data Source={pathToExcel};
Extended Properties=""Excel 12.0 Xml;HDR=YES""
";
//Creating and opening a data connection to the Excel sheet
using (var conn = new OleDbConnection(connectionString))
{
conn.Open();
var cmd = conn.CreateCommand();
cmd.CommandText = $"SELECT * FROM [{sheetName}$]";
using (var rdr = cmd.ExecuteReader())
{
//LINQ query - when executed will create anonymous objects for each row
var query = rdr.Cast<DbDataRecord>().Select(row => new {
Prefix = row[1],
FirstName = row[2],
MiddleName = row[3],
Surname = row[4]
});
//Generates JSON from the LINQ query
var json = JsonConvert.SerializeObject(query);
//Write the file to the destination path
File.WriteAllText(destinationPath, json);
}
}
}
}
}
Through google I tried to add reference but in my project there is no assembly option and it is showing "no items found" in that to check whether system.data is checked or not.See the image also. Can any please tell how to resolve this error?

Important is adding System.Data.dll, because OleDb needs it.
But in your code sample you are already doing it.
Please try to remove the nuget package, clean project, close VS, reinstall package and do a rebuild.

Executing Stored Procedure using C#

I have a procedure named as Get_Added_Request_ID and using this procedure I need to get returned the Request_ID value (VARCHAR2). I have referrd plenty of docs released by Oracle and Microsoft but still I could not find a good solution may be because I am a new learner for Oracle and ASp.NET. Please someone help me in this issue. Thanks in advance
-- Parameter Type Mode Default?
-- ATTR_ VARCHAR2 IN
-- REQUEST_ID VARCHAR2 OUT

Please view this link for the documentation on how to connect to oracle by using oracle data provider
You should use oracle data provider from this link for connecting oracle.
the example code for your scenario will be
Using System;
using System.Collections.Generic;
using System.Text;
using System.Data.OracleClient;
using System.Data;
namespace CallingOracleStoredProc
{
class Program
{
static void Main(string[] args)
{
using (OracleConnection objConn = new OracleConnection("Data Source=*your datasource*; User ID=*Your UserID*; Password=*Your Password*"))
{
OracleCommand objCmd = new OracleCommand();
objCmd.Connection = objConn;
objCmd.CommandText = "Get_Added_Request_ID";
objCmd.CommandType = CommandType.StoredProcedure;
objCmd.Parameters.Add("ATTR_", OracleType.NVarChar).Value = "test";
objCmd.Parameters.Add("REQUEST_ID", OracleType.NVarChar).Direction = ParameterDirection.Output;
try
{
objConn.Open();
objCmd.ExecuteNonQuery();
System.Console.WriteLine("The Request ID is {0}", objCmd.Parameters["REQUEST_ID"].Value);
}
catch (Exception ex)
{
System.Console.WriteLine("Exception: {0}",ex.ToString());
}
objConn.Close();
}
}
}
}

use execute scalar which return 1 row - 1 column value & store it in appropriate variable
For e.g :- SqlHelper.ExecuteScalar(_connectionString, CommandType.StoredProcedure, "Get_Added_Request_ID", null);
note :- ExecuteScalar is came from nuget Microsoft.Application Block

Strange behaviour of OracleDataReader in Read() method

Hi all Oracle experts,
I have a rather strange behaviour of a very very simple program only intended to test basic data acquisition from a remote Oracle database with C#.
I have created a simple C# program as follows:
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using Oracle.ManagedDataAccess.Client;
class Program
{
static void Main(string[] args)
{
var connectionString = "Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP) (HOST={{Server}})(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME={{DataSource}})));User Id={{Username}};Password={{Password}};";
connectionString = connectionString.Replace("{{DataSource}}", "Actual service name");
connectionString = connectionString.Replace("{{Server}}", "Actual Server IP");
connectionString = connectionString.Replace("{{Username}}", "Actual username");
connectionString = connectionString.Replace("{{Password}}", "Actual password");
using (connection = new OracleConnection {ConnectionString = connectionString})
{
connection.Open();
using ( var cmd = connection.CreateCommand() )
{
cmd.CommandText = "SELECT * FROM Table";
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
i++;
}
}
}
}
}
}
The table I am reading from has 220.000 entries, and the problem with the code is, that after an amount of "rows" the reader.Read() just stops. It is supposed to return "false" if there are no more records, and there are still records to come, but the Read() function is called and never returns. Even after letting it try for hours it does not come back.
Does anyone have had a similar experience?
I already heard not to use the Microsoft Oracle Data Driver, so I am using the one from oracle. But still the problem does not go away.
The amount of rows retrieved changes if you change the SQL Command, but also not in a very understandable way: I thought if this has to do with the network buffers I can reduce the columns to get more rows, but it works in the opposite direction. More columns result in more rows.
Any help is deeply appreciated.

Calling class from code behind

I am still new to ASP.net and I'm learning how to call classes. I've looked around for tutorials, but not all are specific to ASP.net 4.0 so I'm not sure if I should apply them.
Right now, I am trying to connect to my SQL database. My webconfig file has been set up with the connectionstring "dbConnectionString" and is working properly when I've tested it with GridViews. What I'd like to do now is access the database from code behind.
I've seen some ways to accomplish this, but I'd like the most efficient, resuable way. I've tried to adopt the answer listed here: How to create sql connection with c# code behind, access the sql server then conditionally redirect? however, I'm getting an error.
I am doing this with C# as a website, not a web application. Here is my code behind for Login.aspx.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using SqlComm; // Is this how I connect to my class from this page????
public partial class Login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
if (Page.IsValid)
{
//no code written yet
}
}
}
My class in the App_Code folder, file name SQLComm.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using System.Web;
/// <summary>
/// SQL Query class
/// </summary>
public class SqlComm
{
// Connection string
static string DatabaseConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["dbConnectionString"].ConnectionString;
// Execute sql command with no value to return
public static void SqlExecute(string sql)
{
using (SqlConnection conn = new SqlConnection(DatabaseConnectionString))
{
SqlCommand cmd = new SqlCommand(sql, conn);
cmd.Connection.Open();
cmd.ExecuteNonQuery();
}
}
// Execute SQL query and return a value
public static object SqlReturn(string sql)
{
using (SqlConnection conn = new SqlConnection(PjSql.dbcs()))
{
conn.Open();
SqlCommand cmd = new SqlCommand(sql, conn);
object result = (object)cmd.ExecuteScalar();
return result;
}
}
// Retrieve an entire table or part of it
public static DataTable SqlDataTable(string sql)
{
using (SqlConnection conn = new SqlConnection(DatabaseConnectionString))
{
SqlCommand cmd = new SqlCommand(sql, conn);
cmd.Connection.Open();
DataTable TempTable = new DataTable();
TempTable.Load(cmd.ExecuteReader());
return TempTable;
}
}
// Execute a stored procedure with 1 parameter
// Returning a value or just executing with no returns
public static object SqlStoredProcedure1Param(string StoredProcedure, string PrmName1, object Param1)
{
using (SqlConnection conn = new SqlConnection(DatabaseConnectionString))
{
SqlCommand cmd = new SqlCommand(StoredProcedure, conn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add(new SqlParameter(PrmName1, Param1.ToString()));
cmd.Connection.Open();
object obj = new object();
obj = cmd.ExecuteScalar();
return obj;
}
}
}
As you can see, I haven't written any code to actually use the class yet, but the "using SQLComm;" line itself is giving me this error:
Compiler Error Message: CS0246: The type or namespace name 'SqlComm' could not be found (are you missing a using directive or an assembly reference?)
As I'm still new, I'm unsure where to go from here. I seem to have included everything contained in the answer on the page I linked above. What else and I missing?
Edit: I read this post regarding a similar issue: asp.NET 2.0 Web Site Can't Access Classes in App_Code
Could this be because I am doing a website and not a web application, so the App_Code folder is being handled differently when I FTP the files over?

using SQLComm means you want to use the namespace SqlComm, which doesn't exist. I think what you want is (somewhere in your codebehind):
DataTable dt = SqlComm.SqlDataTable(...) // call one of the static methods.

You can call it directly.
Given your class has static methods only you'll call it like this:
SqlComm.SqlReturn("select * from table");

So I believe I figured it out. I had my App_Code folder within the subdirectory of my Aspx website, instead of in the root of the server. I moved the folder to the root and now it's working.
I'd be interested in hearing any answers to my edit to my original post though. Since I'm doing this as a website instead of a web application, are there any other issues I will need to keep in mind regarding using classes like this or other issues? I've looked around but haven't seen many differences.
Thanks to everyone for you help!

removing form from c# code?

I'm extremely new to C# and programming anything except for SQL. I've gotten the below code to happen on a Form and on a button click. If I wanted to just make this run on open, how would I do that? I'm very new to C# as you can tell (just started today learning it but its pretty exciting!)
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 Oracle.DataAccess.Client; // ODP.NET Oracle managed provider
using Oracle.DataAccess.Types;
namespace OraTrigger
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
string oradb = "Data Source=OMP1;User Id=user;Password=pass;";
OracleConnection conn = new OracleConnection(oradb); // C#
conn.Open();
OracleCommand cmd = new OracleCommand();
cmd.Connection = conn;
cmd.CommandText = "SELECT cast(Count(*) as varchar(20)) as trig FROM ZDMSN.TRIGGER_TEST";
//cmd.CommandType = CommandType.Text;
OracleDataReader dr = cmd.ExecuteReader();
dr.Read();
int cnt;
if (int.TryParse(dr.GetString(0), out cnt))
{
if (cnt > 0)
{
System.Diagnostics.Process.Start(#"C:\testfile.bat");
}
}
cmd.CommandText = "TRUNCATE TABLE ZDMSN.TRIGGER_TEST";
conn.Dispose();
}
}
}

If you need to run your code as a scheduled task then a command line application is more suitable.
Just create a new project and select Console Application.
Then move all of your button click code inside the Main method written for you by the Visual Studio IDE.
Rembember to set the references to the Oracle ODP.NET library and import the relevant using statements
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Oracle.DataAccess.Client; // ODP.NET Oracle managed provider
using Oracle.DataAccess.Types;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string oradb = "Data Source=OMP1;User Id=user;Password=pass;";
using(OracleConnection conn = new OracleConnection(oradb))
using(OracleCommand cmd = new OracleCommand("SELECT Count(*) as trig FROM ZDMSN.TRIGGER_TEST", conn))
{
conn.Open();
int cnt = (int)cmd.ExecuteScalar();
if (cnt > 0)
{
System.Diagnostics.Process.Start(#"C:\testfile.bat");
cmd.CommandText = "TRUNCATE TABLE ZDMSN.TRIGGER_TEST";
cmd.ExecuteNonQuery();
}
}
}
}
}
I have also revised your code to get a single value from the database. For this case is enough to use the Command.ExecuteScalar method that returns the first column of the first row obtained from your sql command text. Because the count(*) should Always return a single row you could easily cast the return value of ExecuteScalar to your record count variable.
EDIT I have added the logic to TRUNCATE the table involved. Please pay attention that you should use the code provided here. Your code will probably fail because you have an open DataReader and when a DataReader is open you cannot execute other commands (This is true for SqlServer without Multiple Active Result Sets enabled, I really don't know if this rules applies also to the Oracle NET Provider)

Subscribe to Shown or Load event of form and move your code to that event handler.
Form.Shown Event Occurs whenever the form is first displayed.
Form.Load Event Occurs before a form is displayed for the first time.
Also I suggest to extract your code to some Data Access related class, or at least to separate method. And call that method from event handler.