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When I update the database with a new row from the browser, why isn't the SQL Server database table updated? [duplicate]

What is the proper way to create a local-database file and then connect the app to it ? I want it to work even if you change the location of the project folder.
Right know what I do is: Project -> Add new item -> Service-based Database and I create one and then I go to Data -> Add new Data Source, I add the created database and I get the connection string.
Ok, all good, I can connect to it as I wish BUT all my data is erased from the database when I close the application (not always).
For example, this code:
SqlConnection c = new SqlConnection(#"DataSource=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\DB.mdf;Integrated Security=True;User Instance=True");
c.Open();
SqlCommand cmd;
cmd = new SqlCommand("CREATE TABLE Persons (id int primary key, nume char(20), age int)");
cmd.ExecuteNonQuery();
cmd = new SqlCommand("INSERT INTO Persons VALUES (#id, #name, #age)", c);
cmd.Parameters.AddWithValue("#id", 1);
cmd.Parameters.AddWithValue("#name", "Catalin");
cmd.Parameters.AddWithValue("#age", 20);
cmd.ExecuteNonQuery();
I run it first time to create the table and add an item to it and then, then if I run it the second time without the sqlcommand to create the table persons, it tells me that there is no Persons object, BUT if I run the second time the project with the same code, it tells me that there is already a Persons object...
I am using Visual C# Express Edition 2010.

The whole User Instance and AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. MyDatabase)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=MyDatabase;Integrated Security=True
and everything else is exactly the same as before...
Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.

Change the Copy to output directory setting from Copy always to Copy if newer in the property page for your database files. Every time you run the application the new database file is copied from your project to the bin folder, so all of your datas from the previous run are removed.
More: https://msdn.microsoft.com/en-us/library/ms246989.aspx

I figured out a pretty simple answer but maybe it's not the best use to do it this way.
Anyway, I add the database to the project and then I connect directly to it by doing so:
string path = Path.GetDirectoryName(Path.GetDirectoryName(Directory.GetCurrentDirectory)));
SqlConnection c = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename=""" + path + #"Database1.mdf"";Integrated Security=True;User Instance=True");
This way, if you move your project between multiple PCs, the connection will still work (I needed this the most).
This also works with .SDF files and it's easier too.

Insert data into Visual Studio LocalDB in ASP.NET C#

I have a Windows web application and have created a .mdf file in the App_Data folder and I am trying to insert data into the tables already created.
It is able to retrieve codes with a basic SELECT * statement, but I can't insert data, this is the code I have:
private void Update(string username)
{
SqlConnection con = new SqlConnection(#"MYSQLCONNECTION");
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
string bcd = "INSERT INTO NameList(name) VALUES (#paraUsername)";
cmd = new SqlCommand(bcd, con);
cmd.Parameters.AddWithValue("#paraUsername", username);
cmd.ExecuteNonQuery();
list.Update();
con.Close();
}
This code has worked for me in the past, but this time round it does not work. There is no error shown, but the data is not inserted into the table.
This is how I call the method in side my button_click method:
Update(tbName.text);
What might be the problem?

Assuming you have a
AttachDbFileName=......
section in your connection string - then this is a known issue:
The whole AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. YourDatabase)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=YourDatabase;Integrated Security=True
and everything else is exactly the same as before...
Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.

Data not saving permanently to SQL table

I am using C# for a WPF application in Visual Studio Express 2012. I followed the tutorial found here.
I created a testDb.mdf local Service-based database. I open the application, enter text, hit add, and the data adds to the db. I only know this because I have the one field setup as a primary key and unique. If I try to add the same thing again I get an error saying it already exists.
When I exit my application nothing shows in the database. The data I entered is gone. Why is the data not permanent?
Here is the code I'm using for my button click:
private void Add_Click(object sender, RoutedEventArgs e)
{
SqlConnection cn = new SqlConnection(global::testdb.Properties.Settings.Default.testDBConnectionString);
try
{
string sql = "INSERT INTO Test (TestInsert) Values('" + txtName.Text + "')";
SqlCommand cmd = new SqlCommand(sql, cn);
cn.Open();
cmd.ExecuteNonQuery();
MessageBox.Show("Added new record", "Message", MessageBoxButton.OK);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message,"Error", MessageBoxButton.OK);
}
finally
{
cn.Close();
}
}
Connection String:
<connectionStrings>
<add name="testdb.Properties.Settings.testDBConnectionString"
connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\testDB.mdf;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>

It is a common scenario. You have a connection string that uses the substitution string |DataDirectory|. In a desktop application this directory is usually the same directory where your program runs. Inside Visual Studio, your program runs in the BIN\DEBUG (or x86 variant) directory. Thus the Visual Studio copies your MDF file from the project directory to the BIN\DEBUG folder. You add records to this copy, not to the one in the project folder. However, the Visual Studio Server Explorer window has a connection that points to the Project Folder database that, of course, remains empty.
You could add another connection to the Server Explorer pointing to the folder BIN\DEBUG and check that your database has been updated or not.
To complicate the matter, there is the property Copy to the Output Directory associated with the MDF file. If this property is set to Copy Always everytime you start a new session within Visual Studio, the file is copied again from the project folder to the output directory (BIN\DEBUG) overwriting the copy already there with a new empty one. So the first run succeds, the second one fails.
The symptoms that you observed are a clear sign of this situation.
Simply change the property Copy to the Output directory to Copy if newer, the code works well.
(Peraphs it is too early, but remember to change your query to a parameterized query. As is, you could break your code simply inserting a single quote in the txtName textbox like O'Malley, not to mention the Sql Injection hack)

I think your issue is not with the insert code. It's with the way you're checking the database/table yourself. Particularly because you say you're getting primary key errors so something's being added to the table.
Are you sure you're refreshing your view of the table properly? Are you sure you're checking the right table in the right database?

Make sure your initial catalog is set in your connection string, and be sure you are pointing to the right server/ instance of SQL. You may have multiple instances of SQL Server on the same server or whatever DB Server you are using. Also ensure you're going to the right table, of course.
using (SqlConnection cn = new SqlConnection(#"Persist Security Info=False;Integrated Security=true;Initial Catalog=testDB;server=(local)"))
{
string sql = "INSERT INTO Test (TestInsert) Values('" + txtName.Text + "')";
SqlCommand cmd = new SqlCommand(sql, cn);
cn.Open();
cmd.ExecuteNonQuery();
MessageBox.Show("Added new record", "Message", MessageBoxButton.OK);
}
Check in SQL Server Studio that the database exists. I don't recommend using the filename mdf in your code directly using AttachDbFilename. Use the initial catalog.

Well, i found the solution. I solved it by installing SSDT(SQL server data tools) for visual studio. Install it according to your visual studio version. Go to following link to download the SSDT for visual studio.
https://msdn.microsoft.com/en-us/mt186501

In the following of the Steve's answer you can get your database full path in properties window and substitute it with |DataDirectory| in string connection.
your code will be like
conn.ConnectionString = #"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=G:\MhD\c#\phonebook\phonebook\phonebook\tellbook.mdf;Integrated Security=True";

Is there a universal connection string for different computers to connect to a local database using my program developed by vs2010

newbie here.
I have a local db in my program. Whilst I was developing the program I used the SQL
Connection string :
SqlConnection sconn = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\leemk_000\Documents\......Integrated Security=True;User Instance=True;");
Now If I want to load this program onto a different computer I am sure that this connection will no longer work simply because it will still be looking for Users\Lee_000\
I have tried to remove Lee_000 but I get this following error:
An attempt to attach an auto-named database for file C:\Users\Documents..... failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
What can I do to get a connection string to work on different computers.
With many thanks

The whole User Instance and AttachDbFileName= approach is flawed - at best - especially when you want to share your database amongst multiple clients!
When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. YourDatabase)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=YourDatabase;Integrated Security=True
and everything else is exactly the same as before...

If it's a local db you should be placing it within the app folder and carry it with the app right?
Put the database in the App_data folder of your app and use that in your connection string
<add name="YourConnectionString" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\yourfile.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>

You need to use a database server and let your users use it via your connection string like this;
Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;
"myServerAddress" should be the ip adress of your server machine.

Can't connect to my SQL Server database?

I'm creating a very basic CRUD desktop winforms application in C#/.NET 4.0.
Letting Visual Studio auto-generate the fields for the table I'd like to perform my CRUD operations on works just fine, but I'm running into problems when I try and interact with it manually with my own SQL queries.
The auto-generated fields are using the connection string:
Data Source=|DataDirectory|\Data Analysis.sdf
If I try and do:
SqlConnection conn = new SqlConnection(#"Data Source=|DataDirectory|\Data Analysis.sdf");
conn.Open();
It just hangs. What am I missing?

That's a connection string for a SQL Server Compact Edition (CE) database (everything stored inside a single .sdf file) - is that what you're using?
If so : in that case, you'd have to use SqlCeConnection (not a SqlConnection - that's for "grown-up" SQL Server version - not CE)

Maybe try adding some more options to the connection string:
Persist Security Info=False;
File Mode=shared read;

Believe you've specified a relative path to the .sdf file, where you might need to get the executable's runtime folder from System.Environment.CurrentDirectory and prepend it to the filename.