Fill DataTable with two queries in C# - c#

I have multiple tables in a SQL Server database and I am trying to fill a DataTable with two queries on two tables.
This is my code:
String qry = "SELECT Count(*) FROM boss WHERE username ='" + textBox1.Text + "'and password ='" + textBox2.Text + "'; SELECT Count(*) FROM employee WHERE first_name ='" + textBox1.Text + "'and password ='" + textBox2.Text + "' ";
SqlConnection con = new SqlConnection(#"Data Source=(local);Initial Catalog=my_pro;Integrated Security=True");
SqlDataAdapter sda = new SqlDataAdapter(qry, con);
DataTable dt = new DataTable();
sda.Fill(dt);
But this shows me data from boss table. What should I do?

Try this:
String qry = "SELECT Count(*) FROM boss WHERE username ='" + textBox1.Text +
"'and password ='" + textBox2.Text + "' UNION ALL SELECT Count(*) FROM
employee WHERE first_name ='" + textBox1.Text + "'and password ='" + textBox2.Text + "' ";

You need to change the query,
SELECT (
SELECT COUNT(*)
FROM boss
) AS count1,
(
SELECT COUNT(*)
FROM employee
) AS count2
WHERE username ='" + textBox1.Text + "'and password ='" + textBox2.Text + "';

You can use Subquery
SELECT BossCount=(
SELECT COUNT(*)
FROM boss
WHERE username ='" + textBox1.Text + "'and password ='" + textBox2.Text + "'
) ,
EmployeeCount=(
SELECT COUNT(*)
FROM employee
boss WHERE first_name ='" + textBox1.Text + "'and password ='" + textBox2.Text + "'
)

Related

Trying to read data from sql database and show on textboxes - Visual C# (syntax error)

edit: I'm aware of SQL Injection.
First of all, I know my coding methods are terrible but thats what I can for now, extremely beginner on c#.
I'm trying to read data from SQL server and show them on Textboxes.
User going to write (and choose from cmbbox) some data on;
cmbIl.Text, cmbIlce.Text, cmbMahalle.Text, txtAda.Text, txtPafta.Text
and press the button for search.
If that data correspond to the values in sql database (true), some other data will be taken and shown at
txtTapuKodu.Text, txtPafta.Text, txtTapuAlani.Text, txtNitelik.Text,
rtxtImarDurumu.Text
But the code below gives that error:
System.Data.SqlClient.SqlException: 'Incorrect syntax near ','.'
private void btnSorgula_Click(object sender, EventArgs e)
{
string source = #"Data Source=YAGIZ-PC;Initial Catalog=imar_sorgu;Integrated Security=True";
SqlConnection con = new SqlConnection(source);
con.Open();
string sqlSelectQuery = "SELECT * FROM tablo_arsa WHERE il = '" + cmbIl.Text + "', ilce = '" + cmbIlce.Text + "', mahalle = '" + cmbMahalle.Text + "', ada = '" + txtAda.Text + "', parsel = '" + txtParsel.Text + "'";
/* string sqlSelectQuery2 = "SELECT * FROM tablo_arsa WHERE ilce ='" + cmbIlce.Text + "'";
string sqlSelectQuery3 = "SELECT * FROM tablo_arsa WHERE mahalle ='" + cmbMahalle.Text + "'";
string sqlSelectQuery4 = "SELECT * FROM tablo_arsa WHERE ada = " + txtAda.Text;
string sqlSelectQuery5 = "SELECT * FROM tablo_arsa WHERE parsel = " + txtParsel.Text; */
SqlCommand cmd = new SqlCommand(sqlSelectQuery, con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
txtTapuKodu.Text = (dr["tapu_kodu"].ToString());
txtPafta.Text = (dr["pafta"].ToString());
txtTapuAlani.Text = (dr["tapu_alani"].ToString());
txtNitelik.Text = (dr["nitelik"].ToString());
rtxtImarDurumu.Text = (dr["imar_durumu"].ToString());
MessageBox.Show("İstek başarıyla okundu.");
}
else
{
MessageBox.Show("Okuma başarısız.");
}
con.Close();
}
The problem is that your where clause contains commas between the predicates. use AND instead.
change:
string sqlSelectQuery = "SELECT * FROM tablo_arsa WHERE il = '" + cmbIl.Text + "', ilce = '" + cmbIlce.Text + "', mahalle = '" + cmbMahalle.Text + "', ada = '" + txtAda.Text + "', parsel = '" + txtParsel.Text + "'";
to:
string sqlSelectQuery = "SELECT * FROM tablo_arsa WHERE il = '" + cmbIl.Text + "' AND ilce = '" + cmbIlce.Text + "' AND mahalle = '" + cmbMahalle.Text + "' AND ada = '" + txtAda.Text + "' AND parsel = '" + txtParsel.Text + "'";
However, PLEASE read about SQL INJECTION. It is a very bad security issue and this is a perfect example.

How to insert Persian words into a SQL Server database?

I am just wondering how to insert Persian characters into my service-based database?
When I save my data it shows something like '???'.
I have checked such questions like this. But, the solutions were not useful.
private void button1_Click(object sender, EventArgs e)
{
objConnection.Open();
if (ctypeCheckBox.Checked == true)
st = 1;
else if (ctypeCheckBox.Checked == false)
st = 0;
string query = "INSERT INTO LectureTable(Cname, Cid, Ccredit, Csession, Ctype, CstartDate, CendDate, CstartTime, CendTime) VALUES('" + cnameTextBox.Text + "','" + cidTextBox.Text + "','" + ccreditTextBox.Text + "','" + csessionTextBox.Text + "','" + st + "', '" + cstartDateDateTimePicker.MinDate + "', '" + cendDateDateTimePicker.MaxDate + "', '" + cStartTimeBox.Text + "', '" + cEndTimeBox.Text + "')";
SqlDataAdapter SDA = new SqlDataAdapter(query, objConnection);
SDA.SelectCommand.ExecuteNonQuery();
MessageBox.Show("Inserted!");
objConnection.Close();
}
Two things:
Never ever combine your query string with values
"INSERT INTO LectureTable(Cname, Cid, Ccredit, Csession, Ctype, CstartDate, CendDate, CstartTime, CendTime) VALUES('" + cnameTextBox.Text + "','" + cidTextBox.Text + "','" + ccreditTextBox.Text + "','" + csessionTextBox.Text + "','" + st + "', '" + cstartDateDateTimePicker.MinDate + "', '" + cendDateDateTimePicker.MaxDate + "', '" + cStartTimeBox.Text + "', '" + cEndTimeBox.Text + "')";
Should be immediately replaced with
"INSERT INTO LectureTable(Cname, Cid, Ccredit, Csession, Ctype, CstartDate, CendDate, CstartTime, CendTime)
VALUES(#cname, #cid, #ccredit, #csession, #st, #cstartDateDate, #cendDate, #cStartTime, #cEndTimeB)";
and then you should use
SDA.SelectCommand.Parameters.AddWithValue("cname",cnameTextBox.Text);
for all parameters. This will save you from a lot of problems including SQL injection.
In the database your columns should have nvarchar data type.
Good luck
You should use SqlParameter .Giving example of only one parameter.You can add others as same way.
string query = "INSERT INTO LectureTable(Cname) VALUES(#name)";
using(SqlCommand cmd = new SqlCommand(query, SqlConnection))
{
SqlParameter param = new SqlParameter("#name", cnameTextBox.Text);
param.SqlDbType = SqlDbType.String;
cmd.Parameters.Add(param);
.....
}

Error converting data type varchar to numeric in c# program

Please Help me out,This is my database table in sql-server
(empcode varchar(50)
firstname varchar(50)
lastname varchar(50)
gender varchar(50)
address varchar(50)
contactno numeric(18, 0)
bloodgroup varchar(50)
dateofbirth date
country varchar(50)
qid varchar(50)
passportno varchar(50)
passportexpiredate date
designation varchar(50)
doj date
doexpid date
pf_acc_no numeric(18, 0)
agreementstartdate date
agreementenddate date
department varchar(50)
basic_sal numeric(18, 0)
remarks varchar(50)
empimage image)
and I'm Trying to insert my data through c# windows forms but i'm getting error as "Error converting data type varchar to numeric."
Here below is my c# code
private void button2_Click(object sender, EventArgs e)
{
cn.Open();
if (!empid())
{
DialogResult d = new DialogResult();
d = MessageBox.Show("Do You Declare Yourself All The Information Of This Employee Is Correct To Save?", "Message", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (d == DialogResult.Yes)
{
int i = 0;
SqlCommand cmd = new SqlCommand("INSERT INTO Employee(
empcode,firstname,lastname,gender,address,contactno,bloodgroup,
dateofbirth, country,qid,passportno,passportexpiredate,designation,
doj,doexpid,pf_acc_no, agreementstartdate,agreementenddate,
department,basic_sal,remarks,empimage)
VALUES('" + txtempcode.Text + "','" + txtfrstname.Text + "',
'" + txtlstname.Text + "','" + combogender.Text + "','" +
txtaddr.Text + "','" + txtcont.Text + "','" + txtblodgrp.Text + "', '" +
dob.Value.ToString("yyyy/MM/dd") + "' ,'" + txtcountry.Text + "','" + tqid.Text + "','" +
txtpassportno.Text + "', '" + passexpdate.Value.ToString("yyyy/MM/dd") + "' ,'" +
combodesig.Text + "', '" + doj.Value.ToString("yyyy/MM/dd") + "', '" + doexpqid.Value.ToString("yyyy/MM/dd") + "', '" +
txtqibacc.Text + "', '" + agreestartdate.Value.ToString("yyyy/MM/dd") + "','" + agreeenddate.Value.ToString("yyyy/MM/dd") + "' ,'" + combobranch.Text + "','" + txtnetsalary.Text + "','" + txtremark.Text + "',#empimage) ", cn);
MemoryStream stream = new MemoryStream();
pb1.Image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] pic = stream.ToArray();
cmd.Parameters.AddWithValue("#empimage", pic);
i = cmd.ExecuteNonQuery();
if (i > 0)
{
MessageBox.Show("Successfully Inserted Employee Record" + i);
}
cn.Close();
showdata();
clear();
}
}
}
public bool empid()
{
using (SqlConnection con = new SqlConnection("Data Source=SAFIYA-PC;Initial Catalog=dbEmployee;User ID=sa;Password=sa$123"))
{
con.Open();
string query = "select empcode from Employee where empcode = '" + txtempcode.Text + "'";
SqlCommand cmd = new SqlCommand(query, con);
SqlDataReader dr;
dr = cmd.ExecuteReader();
while (dr.Read())
{
empCode = dr["empcode"].ToString();
if (empCode != "0")
{
MessageBox.Show("Id already Existed Please use Another One!!!!!!");
return false;
}
con.Close();
}
return true;
}
}
Edit: the comment below is quite right, the immediate issue is that you have single quotes around the data you are trying to put in the contactno numeric(18, 0) field which is telling SQL to interpret that value as a varchar.
Change "','" + txtcont.Text + "','" to "'," + txtcont.Text + ",'" (i.e. remove the single quotes either side of the text box value) and do the same for any other numeric fields.
However, as is mentioned in other responses, this general approach of concatenating together a sql command string is not recommended from a security point of view. The preferred option is to use a parametrised query.
Using a parametrised query will also make it easier to deal with any nullable fields, as per this example.
(Edited to correct the answer in response to comment from Steffen)
Why don't you use parameters? It prevents your code from SQL Injection and you don't have to convert values and code is much more readable. Look at sample (it is for select statement but the same works for insert/update/delete statement):
var connectionString = "some connection string";
using (var connection = new SqlConnection(connectionString)) {
connection.Open();
using (var command = new SqlCommand("SELECT * FROM Dogs1 WHERE Name LIKE #Name", connection)) {
command.Parameters.Add(new SqlParameter("Name", dogName));
var reader = command.ExecuteReader();
while (reader.Read()) {
int weight = reader.GetInt32(0);
string name = reader.GetString(1);
string breed = reader.GetString(2);
Console.WriteLine("Weight = {0}, Name = {1}, Breed = {2}",
weight,
name,
breed);
}
}
}
You are directly storing the text value of your controls in your numeric fields (contactno, pf_acc_no and basic_sal). Are the values really sql-string representations of numeric values?
I would try to convert them to numeric value
double dValue = 0.0;
double.TryParse(textBox1.Text, out dValue);
and then, in the sql string convert to their sql-string representations with dValue.ToString() or a special dedicated method.
As per your table structure, there are 3 fields that are of numeric datatype. These are - contactno, pf_acc_no and basic_sal
And the values for these fileds are txtcont.Text, txtqibacc.Text and txtnetsalary.Text respectively, And your are also putting ' around them, that is why they are being treated as varchar filed.
While constructing the sql statement, you should pass the values for these fields as numeric, which is to say without ' marks. So just remove ' before and after these fields and your query should work fine.
SqlCommand cmd = new SqlCommand("INSERT INTO Employee(
empcode,firstname,lastname,gender,address,contactno,bloodgroup,
dateofbirth, country,qid,passportno,passportexpiredate,designation,
doj,doexpid,pf_acc_no, agreementstartdate,agreementenddate,
department,basic_sal,remarks,empimage)
VALUES('" + txtempcode.Text + "','" + txtfrstname.Text + "',
'" + txtlstname.Text + "','" + combogender.Text + "','" +
txtaddr.Text + "'," + txtcont.Text + ",'" + txtblodgrp.Text + "', '" +
dob.Value.ToString("yyyy/MM/dd") + "' ,'" + txtcountry.Text + "','" + tqid.Text + "','" +
txtpassportno.Text + "', '" + passexpdate.Value.ToString("yyyy/MM/dd") + "' ,'" +
combodesig.Text + "', '" + doj.Value.ToString("yyyy/MM/dd") + "', '" + doexpqid.Value.ToString("yyyy/MM/dd") + "', " +
txtqibacc.Text + ", '" + agreestartdate.Value.ToString("yyyy/MM/dd") + "','" + agreeenddate.Value.ToString("yyyy/MM/dd") + "' ,'" + combobranch.Text + "'," + txtnetsalary.Text + ",'" + txtremark.Text + "',#empimage) ", cn);
In case you need to pass null to these numeric fields, use DBNull.Value as shown here -
Assign Null value to the Integer Column in the DataTable
Constructing queries like these are prone to SqlInjection, suggest to use parameterized queries instead.
Actually, your code is very vulnerable to SQL-injection attacks. But I don't changing your programming style; I'm changing just your insertion query:
SqlCommand cmd = new SqlCommand(#"
INSERT INTO Employee
(empcode, firstname, lastname, gender, address, contactno,
bloodgroup, dateofbirth, country, qid, passportno, passportexpiredate,
designation, doj, doexpid, pf_acc_no, agreementstartdate, agreementenddate,
department, basic_sal, remarks, empimage)
VALUES
('" + txtempcode.Text + "',
'" + txtfrstname.Text + "',
'" + txtlstname.Text + "',
'" + combogender.Text + "',
'" + txtaddr.Text + "',
" + txtcont.Text + ",
'" + txtblodgrp.Text + "',
'" + dob.Value.ToString("yyyy/MM/dd") + "' ,
'" + txtcountry.Text + "',
'" + tqid.Text + "',
" + txtpassportno.Text + ",
'" + passexpdate.Value.ToString("yyyy/MM/dd") + "' ,
'" + combodesig.Text + "',
'" + doj.Value.ToString("yyyy/MM/dd") + "',
'" + doexpqid.Value.ToString("yyyy/MM/dd") + "',
'" + txtqibacc.Text + "',
'" + agreestartdate.Value.ToString("yyyy/MM/dd") + "',
'" + agreeenddate.Value.ToString("yyyy/MM/dd") + "' ,
'" + combobranch.Text + "',
" + txtnetsalary.Text + ",
'" + txtremark.Text + "',
#empimage) ", cn);

forgot password query failure due to multiple 'and' & or 'claws'

<TD>
con.Open();
string sql = "select password from Login_user where user_name='" + txtname.Text + "' and mobile='" + txtmob.Text + "' and security_question='" + cmbquestion.SelectedText + "' and answer='" + txtanswer.Text + "' || user_name='" + txtname.Text + "' and dob='" + dateTimePicker1.Value.ToString() + "' and security_question='" + cmbquestion.SelectedText + "' and answer='" + txtanswer.Text + "'";
//string sql1 = "select password from Login_user where user_name='" + txtname.Text + "' and mobile='" + txtmob.Text + "' and security_question='" + cmbquestion.SelectedText + "' and answer='" + txtanswer.Text + "'";
cmd = new SqlCommand(sql, con);
dr = cmd.ExecuteReader();
if (dr.Read() == true)
{
MessageBox.Show("Your Password is : " + dr.GetString(0) + ".", "SUCCESSFUL !", MessageBoxButtons.OK, MessageBoxIcon.Information);
con.Close();
this.Hide();
Form1 f = new Form1();
f.Show();
}
else
{
MessageBox.Show("NOT found");
}
con.Close();
dr.Close();
</TD>
i have given a c# code where i have taken query to show a password in a password recovery form and i want all the fields to be compulsory, but only the two fields that are mobile and dob will be either or condition.so any one of them will be given to submit.what will be the code please provide me the correct query for this functionality.
You need to group mobile and dob together within parenthesis and an OR clause.
Besides that, you really need to structure your query so it can be read easier and use parameters for better security and performance.
Try this:
string sql = #"
select password
from Login_user
where user_name=#user_name
and (
mobile=#mobile
OR
dob=#dob
)
and security_question=#security_question
and answer=#answer ";
cmd.Paramaters.AddWithValue("#user_name", txtname.Text);
cmd.Paramaters.AddWithValue("#mobile", txtmob.Text);
cmd.Paramaters.AddWithValue("#answer", txtanswer.Text);
cmd.Paramaters.AddWithValue("#security_question", cmbquestion.SelectedText);
cmd.Paramaters.AddWithValue("#dob", dateTimePicker1.Value.ToString());

How to save a picture to an access database table?

I am using this code to save a picture into an access database table:
byte[] fromPath = File.ReadAllBytes(Picture_Path);
byte[] fromPath2 = File.ReadAllBytes(BacksidePicture_Path);
con.Open();
string query = "Insert Into DML_Books_List (" +
"ID,ISNBORCode, Title, Donor, DocType, Edition, Author1, Author2, Author3, " +
"Author4, Translator, Publisher, Subject, USubject, Shelf, Cost, " +
"Language, Pages, Image, BImage, Description, Date) VALUES ('" +
"2" + "','" + ISNB_AddBook_Books_TXT.Text + "', '" +
Title_AddBook_Books_TXT.Text +
"', '" + Donor_AddBook_Books_TXT.Text + "', '" +
DocType_AddBook_Books_CBE.SelectedItem + "', '" +
Edition_AddBook_Books_TXT.Text + "', '" +
Author1_AddBook_Books_TXT.Text + "', '" +
Author2_AddBook_Books_TXT.Text + "', '" +
Author3_AddBook_Books_TXT.Text + "', '" +
Author4_AddBook_Books_TXT.Text + "', '" +
Translator_AddBook_Books_TXT.Text + "', '" +
Publisher_AddBook_Books_CBE.SelectedItem + "', '" +
Subject_AddBook_Books_CBE.SelectedItem + "', '" +
USubject_AddBook_Books_CBE.SelectedItem + "', '" +
Shelf_AddBook_Books_CBE.SelectedItem + "', '" +
Cost_AddBook_Books_TXT.Text + "', '" +
Language_AddBook_Books_CBE.SelectedItem + "', '" +
Pages_AddBook_Books_TXT.Text + "', '" +
#fromPath + "', '" + #fromPath2 + "', '" +
Description_AddBook_Books_MemoEdit.Text + "', '" +
Date_AddBook_Books_TXT.Text + "')";
OleDbCommand myCommand = new OleDbCommand();
myCommand.CommandText = query;
myCommand.Connection = con;
myCommand.ExecuteNonQuery();
con.Close();
But it has some problems.
Please Help Me solve this problem.
Thank you
OleDb.OleDbConnection cn = new OleDb.OleDbConnection();
cn.ConnectionString = "Provider=Microsoft.Jet.OleDb.4.0; Data Source=" + Application.StartupPath + "\\data.mdb";
cn.Open();
byte[] arrImage = null;
string strImage = null;
IO.MemoryStream myMs = new IO.MemoryStream();
//
if ((this.picPhoto.Image != null)) {
this.picPhoto.Image.Save(myMs, this.picPhoto.Image.RawFormat);
arrImage = myMs.GetBuffer;
strImage = "?";
} else {
arrImage = null;
strImage = "NULL";
}
OleDb.OleDbCommand myCmd = new OleDb.OleDbCommand();
myCmd.Connection = cn;
myCmd.CommandText = "INSERT INTO tblstudent(stdid, [name], photo) " + " VALUES(" + this.txtID.Text + ",'" + this.txtName.Text + "'," + strImage + ")";
if (strImage == "?") {
myCmd.Parameters.Add(strImage, OleDb.OleDbType.Binary).Value = arrImage;
}
Interaction.MsgBox("Data save successfully!");
myCmd.ExecuteNonQuery();
cn.Close();
Source
use parameters like below code:
Assume you have two columns in your table called ID and Image. Now you going to insert data using SQL parameters
you need SQL statement like
Insert Into DML_Books_List(ID, [Image]) values (#id, #image)
#id and #image are the given names for parameters. You can set the parameter values by parameter name.
var pic = File.ReadAllBytes(yourFileName);
using(OleDbConnection con = new OleDbConnection(constr))
using(OleDbCommand cmd = new OleDbCommand("Insert Into DML_Books_List(ID, [Image]) values (#id, #image)", con))
{
con.Open();
cmd.Parameters.AddWithValue("#id", TextBox1.Text);
cmd.Parameters.AddWithValue("#image", pic);
cmd.ExecuteNonQuery();
}
Use parametrized query..
OleDbConnection connection = new OleDbConnection(#"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=database");
OleDbCommand command = connection.CreateCommand();
imageData = ReadByteArrayFromFile(#"c:\test.jpg");
command.CommandText = "Insert into SomeTable (Name, ImageData) VALUES (#Name, #Img)"
command.Parameters.AddWithValue("#Name", "theName");
command.Parameters.AddWithValue("#Img", imageData);
command.ExecuteNonQuery();

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