Develop Reference

"There is no row at position 0 how to fix it"

During find data between two days, getting error "there is no row at position 0"
MySqlConnection connection = new MySqlConnection(ConfigurationManager.ConnectionStrings["Demo"].ConnectionString.ToString());
string str = "select * from sample where name='" + Session["name"] + "' and date between '" + txtfirstdate.Text + "' and '" + txtenddate.Text + "'";
MySqlCommand cmd = new MySqlCommand(str, connection);
MySqlDataAdapter adapter = new MySqlDataAdapter(cmd);
DataSet set = new DataSet();
connection.Open();
adapter.Fill(set);
connection.Close();
//var table = set.Tables[0];
if (set != null)
{
lblname.Text = set.Tables[0].Rows[0]["name"].ToString();
lbldate.Text = set.Tables[0].Rows[0]["date"].ToString();
}

Read the Error Message. Your result set table has no rows.
Replace u r if Condition.
if (set.Tables[0].Rows.Count > 0) {
lblname.Text = set.Tables[0].Rows[0]["name"].ToString();
lbldate.Text = set.Tables[0].Rows[0]["date"].ToString();
}

syntax error (missing operator) in query expression

I'm using c# and this error is becoming headache for me. I do not know how to solve this error .
can anyone help me to solve this. Here is the code
try
{
string MyConnection2 = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\DELL\Documents\db1.mdb";
//Display query
string Query = "select riq_num , department, item_name , item_unit , no_of_stock_out , itemtype from outputdet1 where riq_num = " + textBox2.Text + " or department= '" + comboBox1.Text + " ' or item_name= '" + textBox4.Text + "' or item_unit= '" + comboBox2.Text + "' or no_of_stock_out = " + textBox6.Text + " or itemtype = '" + comboBox3.Text + "' ; ";
OleDbConnection MyConn2 = new OleDbConnection(MyConnection2);
OleDbCommand MyCommand2 = new OleDbCommand(Query, MyConn2);
MyConn2.Open();
//For offline connection we will use MySqlDataAdapter class.
OleDbDataAdapter MyAdapter = new OleDbDataAdapter();
MyAdapter.SelectCommand = MyCommand2;
DataTable dTable = new DataTable();
MyAdapter.Fill(dTable);
// here i have assign dTable object to the dataGridView1 object to display data.
dataGridView1.DataSource = dTable;
MyConn2.Close();
}
// OleDbCommand MyCommand2 = new OleDbCommand(Query, MyConn2);
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

I assumed that textBox2.Text & textBox6.Text return a string from textbox control, so that OleDbCommand will throwing exception when it contains empty value or any non-numeric string since it will form invalid SQL statement. Use parameterized query like this example:
string Query = #"select riq_num, department, item_name, item_unit, no_of_stock_out, itemtype
from outputdet1
where riq_num = #riq_num
or department= #department
or item_name= #item_name
or item_unit= #item_unit
or no_of_stock_out = #no_of_stock_out
or itemtype = #itemtype";
using (OleDbConnection MyConn2 = new OleDbConnection(MyConnection2))
{
using (OleDbCommand MyCommand2 = new OleDbCommand(Query, MyConn2))
{
MyConn2.Open();
MyCommand2.Parameters.Add("#riq_num", textBox2.Text);
MyCommand2.Parameters.Add("#department", comboBox1.Text);
MyCommand2.Parameters.Add("#item_name", textBox4.Text);
MyCommand2.Parameters.Add("#item_unit", comboBox2.Text);
MyCommand2.Parameters.Add("#no_of_stock_out", textBox6.Text);
MyCommand2.Parameters.Add("#itemtype", comboBox3.Text);
// execute the query here
}
}
Remember that using statements used to dispose OLEDB connection immediately after it has closed so that GC can free up resources.
Additional note:
OleDbParameter works with parameter order instead of named parameters, hence ensure that the parameters are declared in their proper order from first to last.

Read a sql query with C# [duplicate]

This question already has answers here:
ExecuteNonQuery: Connection property has not been initialized.
(7 answers)
Closed 7 years ago.
I tried to get my sql query read, but it does not really work. It is all working until it comes to the query part and then on the line:
rst = query.ExecuteReader();
It gets an error:
Connection property has not been initialized.
Does anyone know how to handle this?
Chart chart = new Chart();
StringBuilder xmlStr = new StringBuilder();
StringBuilder strCategories = new StringBuilder();
StringBuilder strProcesses = new StringBuilder();
StringBuilder strTasks = new StringBuilder();
xmlStr.Append("<chart logoURL='../../Images/Piktogramme/" + chart.Image + "' caption='" + chart.Caption + "' theme='flat'" + " dateformat='dd/mm/yyyy' showTaskLabels='1'>"); // attributes will go here
// Category for each month
for (int i = -12; i < 6; i++)
{
DateTime today = DateTime.Now;
today = today.AddMonths(i);
strCategories.Append("<category start='1/" + today.Month + "/" + today.Year + "' end='" + DateTime.DaysInMonth(today.Year, today.Month) + "/" + today.Month + "/" + today.Year + "' name='" + today.ToString("MMM") + "' />");
}
// Get the connection string
string connStr = ConfigurationManager.ConnectionStrings["CRM_SQL"].ConnectionString;
using (SqlConnection conn = new SqlConnection(connStr))
{
// Establish the connection with the database
conn.Open();
// Construct and execute SQL query which would return the total amount of sales for each year
SqlCommand query = new SqlCommand();
// Begin iterating through the result set
SqlDataReader rst;
query.CommandText = "SELECT * from table";
rst = query.ExecuteReader();
while (rst.Read())
{
// Construct the chart data in XML format
strProcesses.AppendFormat("<process name='{1}' id='{0}' />", rst[0], rst[1]);
strTasks.AppendFormat("<task name='{0}' processid='{1}' start='{2}' end='{3}' />", rst[4], rst[0], rst[2], rst[3]);
}
DateTime today = DateTime.Now;
xmlStr.Append("<trendlines><line start='" + DateTime.DaysInMonth(today.Year, today.Month) + "/" + today.Month + "/" + today.Year + "' displayvalue='Heute'/></trendlines>");
// End the XML string
xmlStr.Append("<categories>" + strCategories.ToString() + "</categories> <processes>" + strProcesses.ToString() + "</processes> <tasks width='10'>" + strTasks.ToString() + "</tasks> </chart>");
// Close the result set Reader object and the Connection object
rst.Close();
conn.Close();
}
return xmlStr.ToString();
}

Your SqlCommand object has no link to your SqlConnection.
Replace the line:
SqlCommand query = new SqlCommand();
By:
SqlCommand query = conn.CreateCommand();
PS: Like SqlConnection, SqlCommand and SqlDataReader are also disposable, so you can/should also use using.
And the line conn.Close(); is useless because using will take care of it.

One way to do this;
var query = new SqlCommand("SELECT * from table", conn);
another way is assigning the connection string
query.connection = conn;

Add following
query.Connection=conn;
after
SqlCommand query = new SqlCommand();

try this :
using (SqlConnection conn = new SqlConnection(connStr))
{
// Establish the connection with the database
conn.Open();
using (SqlCommand query = new SqlCommand("SELECT * from table", conn))
{
query.CommandType = CommandType.Text;
using (var rst = query.ExecuteReader())
{
while (rst.Read())
{
strProcesses.AppendFormat("<process name='{1}' id='{0}' />", rst[0], rst[1]);
strTasks.AppendFormat("<task name='{0}' processid='{1}' start='{2}' end='{3}' />", rst[4], rst[0], rst[2], rst[3]);
}
}
}
DateTime today = DateTime.Now;
xmlStr.Append("<trendlines><line start='" + DateTime.DaysInMonth(today.Year, today.Month) + "/" + today.Month + "/" + today.Year + "' displayvalue='Heute'/></trendlines>");
// End the XML string
xmlStr.Append("<categories>" + strCategories.ToString() + "</categories> <processes>" + strProcesses.ToString() + "</processes> <tasks width='10'>" + strTasks.ToString() + "</tasks> </chart>");
conn.Close();
}

exporting dataset to sqlite3 database using c# application errors sqlexception unhandled

I am very new to sqlite and c# and trying exporting a csv file to sqlite database using dataset.
but I get this error.
SQL logic error or missing database
no such column: P17JAW
code:
string strFileName = "I:/exploretest.csv";
OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OleDb.4.0; Data Source = " + System.IO.Path.GetDirectoryName(strFileName) + "; Extended Properties = \"Text;HDR=YES;FMT=Delimited\"");
conn.Open();
OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM " + System.IO.Path.GetFileName(strFileName), conn);
DataSet ds = new DataSet("Temp");
adapter.Fill(ds);
DataTable tb = ds.Tables[0];
SQLiteConnection m_dbConnection;
m_dbConnection = new SQLiteConnection("Data Source= C:/Users/WebMobility.db; Version=3;");
m_dbConnection.Open();
var dt = ds.Tables[0];
foreach (DataRow dr in dt.Rows)
{
var Id = dr["Id"].ToString();
var VRM = dr["VehicleRegistration"].ToString();
var Points = Convert.ToInt32(dr["TicketScore"].ToString());
string sql = "insert into NaughtyList (Id,VRM,Points) values ( '" + Id + "'," + VRM + "," + Points + ")";
SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();
}
m_dbConnection.Close();
}
CSV FILE CONTAINS
Id,VehicleRegistration,TicketScore
21,P17JAW,1
22,K1WOM,1
23,m4npr,4
25,G7EPS,4

Your problem is with the single quotes missing for VRM your query should be like:
string sql = #"insert into NaughtyList (Id,VRM,Points) values
( '" + Id + "','" + VRM + "'," + Points + ")";
//^^ ^^
From the values it appears that ID is of integer type, you can remove single quotes around ID.
You should parameterized your query that will save your from these errors. I am not sure if parameters are supported by SQLiteCommand if they are you can do something like:
string sql = #"insert into NaughtyList (Id,VRM,Points) values
(#Id,#VRM,#Points)";
and then
command.Parameters.AddWithValue("#id", Id);
command.Parameters.AddWithValue("#VRM", VRM);
command.Parameters.AddWithValue("#Points", Points);

Problem in using DataSet

I have first manually created a DataSet in my project name recvd.xsd having corresponding recvd.xss. On my button click event i have done the following coding.
try
{
DataSet recvd_REPORT = new DataSet();
DataTable REPORT = new DataTable();
String dd_webCofig = ConfigurationManager.ConnectionStrings["server2"].ConnectionString;
OdbcConnection ddlistconn = new OdbcConnection(dd_webCofig);
ddlistconn.Open();
REPORT = recvd_REPORT.Tables["REPORT"];
DataColumn myDataColumn = new DataColumn();
myDataColumn.DataType = typeof(System.Int32);
myDataColumn.ColumnName = "RECEIVED";
myDataColumn.ReadOnly = false;
myDataColumn.Unique = false;
// Add the Column to the DataColumnCollection.
REPORT.Columns.Add(myDataColumn);
string query = "SELECT case_no as \"RECEIVED\" from dcpanaji.Civil_t where dt_regis > '" + txtStartDate.Text + "' AND dt_regis < '" + txtEndDate.Text + "' AND court_no = " + DropDownList1.SelectedItem + "";
Response.Write(query);
OdbcCommand cmd = new OdbcCommand(query, ddlistconn);
OdbcDataReader loginMyReader = cmd.ExecuteReader();
OdbcDataAdapter adptr = new OdbcDataAdapter(query, ddlistconn);
adptr.Fill(REPORT);
ddlistconn.Close();
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
I am getting the error as
Object reference not set to an instance of an object.
If i remove as \"RECEIVED\" from my SQL query and simply execute my SQL query than the result of my query is as follows (varies depending on user input)
200200000452011 ......, n numbers of 12 digit number.
Please help me to remove the error as to why am i not able to bind to DataTable.
I am getting the error before Response.Write(query); is executed, why is that problem?
I removed the try catch block and now i get the error as

try
SELECT case_no as `RECEIVED` ...
or just
SELECT case_no as RECEIVED ...
Anyway the correct DataSet filling code should look like this:
DataSet ds = new DataSet();
using (OdbcConnection connection = new OdbcConnection(connectionString))
using (OdbcCommand command = new OdbcCommand(sqlQuery, connection)
using (OdbcDataAdapter adapter = new OdbcDataAdapter(command)
{
adapter.Fill(ds);
}

In your SQL instead of \"RECIEVED\" have you tried just RECIEVED, no quotes?

You need not to use \"RECEIVED\" in the query, you can use like below.
query = "SELECT case_no as [RECIEVED] from dcpanaji.Civil_t where dt_regis > '" + txtStartDate.Text + "' AND dt_regis < '" + txtEndDate.Text + "' AND court_no = " + DropDownList1.SelectedItem + "";

you can write query as like
query = "SELECT case_no as RECIEVED from dcpanaji.Civil_t where dt_regis > '" + txtStartDate.Text + "' AND dt_regis < '" + txtEndDate.Text + "' AND court_no = " + DropDownList1.SelectedItem + "";
check like that....