I created a database in sql server express edition, in that i create a table called employee. Now i am able to inserting rows(records) dynamically into table successfully, and i can also read those records successfully. But the problem is the values which are inserted dynamically are stored temporarily. When i close and reopen the application the previous inserted records are not available. can u please suggest me what can i do to save records permanently into the database.
thanking you.....
This is my code used to inserting the records into sql server database. Please help me out of this problem...
namespace VACS_practice
{
public partial class Form1 : Form
{
string m_sVehicleNo, m_sName, m_sFlatNo, m_sImagpath;
System.Data.SqlClient.SqlConnection Con;
System.Data.SqlClient.SqlCommand Cmd;
string ConString = #"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\VACSDB.mdf;Integrated Security=True;User Instance=True";
public Form1()
{
InitializeComponent();
}
private void btnAddClick(object sender, EventArgs e)
{
Con = new SqlConnection(ConString);
m_sVehicleNo = m_VehicleNo.Text;
m_sName = m_Name.Text;
m_sFlatNo = m_Phno.Text;
//m_sImagpath = m_ImgPath.Text;
Cmd = new SqlCommand("INSERT INTO ResidentDB ([R_VehNo],[R_Name],[R_PhNo]) VALUES ('" + m_sVehicleNo + "','" + m_sName + "','" + m_sFlatNo + "')", Con);
Con.Open();
Cmd.ExecuteNonQuery();
Con.Close();
MessageBox.Show("Inserted successfully");
// this.Close();
}
Almost certainly you are not committing your changes. If you are running transactions then you must commit.
Alternatively, you are making changes in your in-memory versions, that are not connected to the database at all.
Related
Probably the worst part about using Microsoft Access and SQL is trying to connect through the OLEDB connection. The code is on the one drive and has been working without issue but this morning it has came up with this error;
"System.InvalidOperationException: 'The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine.'"
Previously I was able to change the CPU from any to x86 which sometimes seemed to fix the problem but now it is not. I am running System.Data.OleDb 7.0.0 which I have not changed since starting this protect.
using System.Data.OleDb;
using System.Data;
using System;
namespace LOGIN_TAKE_FIVE
{
public partial class Form1 : Form
{
OleDbConnection connection = new OleDbConnection();
public Form1()
{
InitializeComponent();
connection.ConnectionString = (#"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=C:/Users/kiera/LOGIN TAKE FIVE/bin/Debug/net6.0-windows/dbNumber2.accdb");
}
private void btnAdd_Click(object sender, EventArgs e)
{
connection.Open();
OleDbCommand cmd = new OleDbCommand();
string encryptUser = EncryptString(tbUsername.Text);
string encryptPassword = EncryptString(tbPassword.Text);
string regSQL = "INSERT INTO Users ([Username], [Password]) VALUES ('" + encryptUser + "', '" + encryptPassword + "')";
cmd = new OleDbCommand(regSQL, connection);
cmd.ExecuteNonQuery();
connection.Close();
}
this code was working in full no less than 5 days ago so I am unsure what the problem is. Any help would be greatly appreciated.
I have written this simple code in c# VS 2010 to store the name and login to my local table. When i run it is shows me this massage:
"incorrect syntax near the nvarchar"
using System;
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
string name =textBox1.Text;
string login =textBox2 .Text;
string sqlquery;
SqlConnection cn = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename= C:\\Users\\Safeen\\Documents\\Visual Studio 2010\\Projects\\WindowsFormsApplication12\\WindowsFormsApplication12\\Database1.mdf;Integrated Security=True;User Instance=True");
cn.Open();
sqlquery = "INSERT INTO Table1 (user, password) VALUES ('" + name + "','" + login + "')";
try
{
SqlCommand command = new SqlCommand(sqlquery, cn);
command.Parameters.AddWithValue("#user ", textBox1.Text);
command.Parameters.AddWithValue("#password ", textBox2.Text);
command.ExecuteNonQuery();
MessageBox.Show("Table1 Added");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
textBox1.Clear();
textBox2.Clear();
cn.Close();
}
}
You're providing multiple values for your parameters.
You're saying the db value of user = name and password = login, then ALSO passing in two parameters called #user and #password, without telling SQL which set is correct.
You definitely want to go with SqlCommand option and also set the SqlCommand.CommandType to the correct value. Assigning parameters like this is safe; dropping variables directly into the VALUES() clause (like you had in your original post) can open yourself to SQL Injection attacks.
I edited out a recommendation to use Stored Procs here. That's more of a personal preference I have, as per the little discussion in the comments; I like to separate out my database layer. Also, it means that if anything ever changes you just have to update your Stored Proc once instead of finding your query everywhere it could be in your app.
I am trying to rebuild an application that originally used sqlite to now use 'localdb'. (I want an application that can create its own database locally and at runtime without requiring a pre-installed instance of sql server or sql express on the target machine)
I want to move away from using a 'third party' library (sqlite) as experience has told me it can be a pain to get it working from scratch, and towards something supposedly more straightforward to get up and running from scratch.
Using code copied (and slightly modified) from the web I have managed to create an mdf file dynamically/programmatically, but I am puzzled by what happens if I run it more than once, even if I choose a new filename each time. Namely it seems to somehow keep the changes/additions made on each run. Below is the relevant code...
public partial class Form1 : Form
{
SqlConnection conn;
public void CreateSqlDatabase(string filename)
{
string databaseName =
System.IO.Path.GetFileNameWithoutExtension(filename);
conn = new SqlConnection(
String.Format(
#"Data Source=(LocalDB)\v11.0;Initial Catalog=master;Integrated Security=True"
));
conn.Open();
using (var command = conn.CreateCommand())
{
command.CommandText =
String.Format(
"CREATE DATABASE {0} ON PRIMARY (NAME={0}, FILENAME='{1}')"
, databaseName, filename);
command.ExecuteNonQuery();
command.CommandText =
String.Format("EXEC sp_detach_db '{0}', 'true'", databaseName);
command.ExecuteNonQuery();
}
conn.Close();
}
private void button1_Click(object sender, EventArgs e)
{
if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
CreateSqlDatabase(openFileDialog1.FileName);
}
}
private void button2_Click(object sender, EventArgs e)
{
conn.Open();
SqlCommand comm = conn.CreateCommand();
comm.CommandText =
"create table mytable (id int, name nvarchar(100))";
comm.ExecuteNonQuery();
comm.CommandText =
"insert into mytable (id,name) values (10,'testing')";
comm.ExecuteNonQuery();
comm.CommandText = "select * from mytable";
SqlDataReader reader = comm.ExecuteReader();
while (reader.Read())
{
textBox1.Text +=
reader["id"].ToString() + ", " + reader["name"].ToString() + "\r\n";
}
conn.Close();
}
}
If I run the app once It runs through fine.
If I run the app a second time, and choose a different filename for the database it tells me 'mytable' already exists.
If I comment out the create table code it runs, but the select query returns multiple rows indicating multiple inserts (one for each time the app runs)
I am just seeking to understand why this happens. Do I need to delete database/table each time if I want the app to behave as if it has created the database/table from scratch on each subsequent run?
You have initial catalog 'master' in your connection string. Are you sure you haven't created the tables in the master database instead of the newly created database?
After the creation & detach of the database file, you could try and change your connection to:
SqlConnection con = new SqlConnection(#"Data Source=(LocalDB)\v11.0;Integrated Security=True;AttachDbFilename=c:\xxx\xxx\xxx.mdf");
I have been working on a project related to database (.mdf). I have created some windows forms in visual studio using C#. Basically these forms work together to store, update and delete data from the Service Based Database i created.
The problem is when i build the project, it builds fine, no errors. It inserts a data provided from textboxes to the datagridview too as intended. But as soon as i stop the current debugging, and then rerun it again, all the data provided previously is lost from the datagridview!!
I cant understand why this is happening. anyone please help me. Im totally new to this stuff.. a bit of guidance would be heartily appreciated.
when i had previously used MySQL for the same purpose, the updated data would be permanently stored to the database, but since i migrated from the MySQL to SQL Server's Service Based Database, i get such confusing error.
......
void loadData()
{
SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["baikalpik_bidhut_sewaConnectionString"].ToString());
SqlCommand cmd = new SqlCommand("SELECT SNo,Customer_ID, Citizenship_No, Name, Subscription_Date, Phone_No, Location,Locality,Bulbs,Deposit,Monthly_Charge FROM customerinformation;", con);
try
{
SqlDataAdapter adp = new SqlDataAdapter();
adp.SelectCommand = cmd;
DataTable dt = new DataTable();
adp.Fill(dt);
dataGridViewCustomerInformation.DataSource = dt;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void buttonAdd_Click(object sender, EventArgs e)
{
try
{
float m_chrg = Convert.ToInt64(textBoxBulbs.Text)*500;
SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["baikalpik_bidhut_sewaConnectionString"].ToString());
SqlCommand cmd = new SqlCommand("INSERT INTO customerinformation(SNo,Customer_ID,Citizenship_No,Name,Subscription_Date,Location,Locality,Bulbs,Deposit,Phone_No,Monthly_Charge) values('" + textBoxSNo.Text + "','" + textBoxCustomerID.Text + "','" + textBoxCitizenshipNumber.Text + "','" + textBoxName.Text + "','" + textBoxSubscriptionDate.Text + "','" + textBoxLocation.Text + "','" + textBoxLocality.Text + "','" + textBoxBulbs.Text + "','" + textBoxDeposit.Text + "','" + textBoxPhoneNumber.Text + "','" + m_chrg + "')", con);
con.Open();
SqlDataReader reader = cmd.ExecuteReader();
dt = new DataTable();
dt.Load(reader);
con.Close();
dataGridViewCustomerInformation.DataSource = dt;
loadData();
MessageBox.Show("Entry Added!");
fillListbox();
textBoxSNo.Clear();
textBoxBulbs.Clear();
textBoxCitizenshipNumber.Clear();
textBoxCustomerID.Clear();
textBoxDeposit.Clear();
textBoxLocality.Clear();
textBoxLocation.Clear();
textBoxPhoneNumber.Clear();
textBoxName.Clear();
textBoxSubscriptionDate.Clear();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
If you have your MDF listed in your project files then the property Copy To Output Directory handles how your MDF file is copied to the output directory (BIN\DEBUG or BIN\RELEASE).
If this property is set to Copy Always, then when you run your program a fresh copy of your database file is copied from the project folder to the output effectively destroying every data that you have inserted, modified, deleted in the previous run of your program.
The best solution to this dilemma is to add the MDF file as a permanent database inside your current install of Sql Server and adjust your connection string. And of course set the property to Copy Never
In alternative you could set to Copy if newer. This will allow to change the database schema inside the Server Explorer and let the Visual Studio IDE copy the new structure only after you have made changes.
UPDATE BUT IMPORTANT Not related to your actual question, but your insert query is a serious problem. Do not use string concatenation to build a sql command text. Particularly if the partial text comes from user input. You could face syntax errors (if someone places a single quote inside a text box) or worst, a Sql Injection problem (see here for a funny explanation)
To find good examples of Insert search for 'parametrized query'
After setting up my SqlDataSource on another page to display the values, they come up as 2 blanks for the 2 times I entered test values on the comments page.
I think I'm missing something in getting them into the table in the SQL Server database value?
I'm not sure what information is needed here, so please inform me.
Thanks in advance
EDIT #1 for user request for CODE
protected void btnSend_Click(object sender, EventArgs e)
{
Page.Validate("vld2");
SendMail();
lblMsgSend.Visible = true;
//SQL Server Database
SqlConnection conn; //manages connection to database
SqlCommand cmd; //manages the SQL statements
string strInsert; //SQL INSERT Statement
try
{
//create a connection object
conn = new SqlConnection("Data Source=localhost\\sqlexpress;" +
"Initial Catalog=RionServer;" +
"Integrated Security=True;");
//Build the SQL INSERT Document
strInsert = "INSERT INTO CommentsAdmin (Name,Phone,Email,Comments)"
+ "VALUES(#Name,#Phone,#Email,#Comments);";
//associate the INSERT statement with the connection
cmd = new SqlCommand(strInsert, conn);
//TELL the SqlCommand WHERE to get the data from
cmd.Parameters.AddWithValue("Name", txtName.Text);
cmd.Parameters.AddWithValue("Phone", txtPhone.Text);
cmd.Parameters.AddWithValue("Email", txtEmail.Text);
cmd.Parameters.AddWithValue("Comments", txtComment.Text);
//open the connection
cmd.Connection.Open();
//run the SQL statement
cmd.ExecuteNonQuery();
//close connection
cmd.Connection.Close();
//display status message on the webpage
lblMsgSend.Text = "Thank you for the comment! Please hit the 'Return to Main Page' to return to the Main Page!";
}
catch (Exception ex)
{
lblMsgSend.Text = ex.Message;
}
txtPhone.Text = "";
txtEmail.Text = "";
txtName.Text = "";
txtComment.Text = "";
}
EDIT #2
The values seems to be empty for the Name, Phone, Email, and Comments in the database and when I test the query, so I think it's registering the entries, just not taking the values into the SQL?
EDIT #3
Due to a suggestion by coder and rs, I've done what they've said. And now I get this error.
"String or binary data would be truncated. The statement has been terminated."
The code has been updated as well.
EDIT #4
This question is a follow up for SQL Server Error, 'Keyword not supported 'datasource'.
Remove all the "" similar to this txtPhone.Text = ""; before entering values to SQL as Server you're entering null values to that. So even if you give some values to the textbox it takes predefined NULL values and it dosen't enter either of them.