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How to connect to mysql without using plain text?

I'm trying to make it so i can use username/password i've set in the properties/settings to connect to mysql as i dont want to store mysql details in plaintext here what i'm using but not sure how to go about reading the username/password from properties, Could anyone help? thanks
private void PassTextBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
try
{
string MyConnection = "datasource=localhost;port=3309;username=user;password=pass123";
MySqlConnection MyConn = new MySqlConnection(MyConnection);
MySqlCommand MyCommand = new MySqlCommand("select * from applogin.users where UserId='" + this.UserTextBox.Text + "' and UserPassword='" + this.PassTextBox.Text + "' ;", MyConn);
MySqlDataReader MyReader;
recby = UserTextBox.Text;
MyConn.Open();
MyReader = MyCommand.ExecuteReader();
int count = 0;
while (MyReader.Read())
{
Console.WriteLine(MyReader[count]);
count++;
}
if (count == 1)
{
MessageBox.Show("Accepted, Welcome!");
this.Hide();
Form5 f5 = new Form5();
f5.ShowDialog();
}
else if (count > 1)
{
MessageBox.Show("Duplicate Username and passwor.\nAccess denied.");
}
else
{
MessageBox.Show("Username and password is incorrect.\nPleas try again.");
}
MyConn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}

class DBConnect
{
private MySqlConnection connection;
private string server;
private string database;
private string uid;
private string password;
//Constructor
public DBConnect()
{
Initialize();
}
//Initialize values
private void Initialize()
{
server = "localhost";
database = "connectcsharptomysql";
uid = "username";
password = "password";
string connectionString;
connectionString = "SERVER=" + server + ";" + "DATABASE=" +
database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";
connection = new MySqlConnection(connectionString);
}
//open connection to database
private bool OpenConnection()
{
bool flag=false;
if (this.OpenConnection() == true)
{
//Create Mysql Command
MySqlCommand cmd = new MySqlCommand(query, connection);
//ExecuteScalar will return one value
Count = int.Parse(cmd.ExecuteScalar()+"");
flag=true;
//close Connection
this.CloseConnection();
return flag;
}
else
{
return flag;
}
}
}

I would rather recommend to read password from an environment variable instead of hardcoding it in the code.

This is a broad topic.
Mainly, it is "how to store a 'secret' well?"
I'll give some hints.
First, in dotnet CORE, there is new stuff.
https://learn.microsoft.com/en-us/aspnet/core/security/app-secrets?view=aspnetcore-3.1&tabs=windows
That is for local development, BUT AT LEAST forces you to think about where that secret is being stored.
Using .ini, .config, .txt files and keeping a secret in plain text IS NOT secure for production scenarios.
So then you have to start thinking about "how is my code deployed?"
If you are deploying to Azure, there is Azure Key Vault.
If you are deploying to a machine/VM, then you have to consider something more robust, like Hashicorp Vault.
But you're going to get a few "quick fix" answers. You need to really consider where you keep this secret for your deployed code.

If I read your question correctly, you don't care about the connection string userid/password but about the users login credentials.
This is based on your line:
MySqlCommand MyCommand = new MySqlCommand("select * from applogin.users where UserId='" + this.UserTextBox.Text + "' and UserPassword='" + this.PassTextBox.Text + "' ;", MyConn);
And it appears you are asking about how to encrypt the password so that someone can't monitor the communication. Of course, your connection string is already an issue, but back to what I believe is your question.
It's not clear if you are using the actual user name and password as entered or not. If so, the easiest option is to use 1 way encryption - and only store the encrypted values. Then your code would get the value of the textbox and encrypt it. Then execute a query with the encrypted value (preferably with those encrypted values as parameters, not inline text.)
The result would be a query that might look like:
select * from applogin.users where UserId='kajsdf09823rcfs98dsjssdf' and UserPassword='j;las9onq;p;9wf;kjadf' ;
and written correctly (assuming you have a method named encrypt that implements whatever encryption you choose):
userId = new SqlParameter("#userName", encrypt(this.UserTextBox.Text));
userpw = new SqlParameter("#userPw", encrypt(this.PassTextBox.Text));
cmd.Parameters.Add(userId);
cmd.Parameters.Add(userpw );
cmd.CommandText = "select * from applogin.users where UserId=#userName and UserPassword=#userPw ;";
There are other great suggestions as well, I encourage you to follow up on those as well.

SqlConnection in VS2015 C#

I am extremely new to C# web development (or any development for that matter) but I am trying to figure out how to save the results from a SQL query to a variable. I think I understand the process, but many of the examples I am finding on the Web use a SqlConnection statement. My copy of Visual Studio does not seem to have that command (pretty sure I am using the wrong word here). What am I missing either softwarewise or knowledgewise accomplish my task?
Thank you in advance for your help.
Dep

It depends on what you want to do: insert, update, get data. It also depends if you want to use an ORM library or not. I all depends. The code that I copy below is an example of how to retrieve a DataTable using Ado.Net (as you mentioned SqlConnection):
You have to use:
using System.Data;
using System.Data.SqlClient;
This is the code for retrieving a DataTable
private DataSet ExecuteDataset(string query)
{
var conn = new SqlConnection("Data Source=" + Server + ";Initial Catalog=" + Database + ";User Id=" + Username + ";Password=" + Password + ";");
DataSet ds;
try
{
conn.Open();
ds = new DataSet();
var da = new SqlDataAdapter(query, conn);
da.Fill(ds);
}
catch (Exception)
{
throw;
}
finally
{
conn.Dispose();
conn.Close();
}
return ds;
}
private DataSet ExecuteDataset(string query, SqlParameter[] parametros)
{
var conn = new SqlConnection("Data Source=" + Server + ";Initial Catalog=" + Database + ";User Id=" + Username + ";Password=" + Password + ";");
DataSet ds;
try
{
conn.Open();
SqlCommand command = conn.CreateCommand();
command.CommandText = query;
foreach (SqlParameter p in parametros)
{
command.Parameters.Add(p);
}
ds = new DataSet();
var da = new SqlDataAdapter(command);
da.Fill(ds);
}
catch (Exception)
{
throw;
}
finally
{
conn.Dispose();
conn.Close();
}
return ds;
}
This is the code for running a query that does not expect result with and without parameters:
private void ExecuteNonQuery(string query)
{
var conn = new SqlConnection("Data Source=" + Server + ";Initial Catalog=" + Database + ";User Id=" + Username + ";Password=" + Password + ";");
try
{
conn.Open();
SqlCommand command = conn.CreateCommand();
command.CommandText = query;
command.ExecuteNonQuery();
}
catch (Exception)
{
throw;
}
finally
{
conn.Dispose();
conn.Close();
}
}
private void ExecuteNonQuery(string query, SqlParameter[] parametros)
{
var conn = new SqlConnection("Data Source=" + Server + ";Initial Catalog=" + Database + ";User Id=" + Username + ";Password=" + Password + ";");
try
{
conn.Open();
SqlCommand command = conn.CreateCommand();
command.CommandText = query;
foreach (SqlParameter p in parametros)
{
command.Parameters.Add(p);
}
command.ExecuteNonQuery();
}
catch (Exception)
{
throw;
}
finally
{
conn.Dispose();
conn.Close();
}
}

Here is the simplest example I can think of, take note of the using statements and comments
using System;
using System.Data;
using System.Data.SqlClient;
namespace DataAccess
{
class Program
{
static void Main(string[] args)
{
//Use your database details here.
var connString = #"Server=localhost\SQL2014;Database=AdventureWorks2012;Trusted_Connection=True;";
//Enter query here, ExecuteScalar returns first column first row only
//If you need to return more records use ExecuteReader/ExecuteNonQuery instead
var query = #"SELECT [AccountNumber]
FROM [Purchasing].[Vendor]
where Name = #Name";
string accountNumber = string.Empty;
//Using statement automatically closes the connection so you don't need to call conn.Close()
using (SqlConnection conn = new SqlConnection(connString))
{
SqlCommand cmd = new SqlCommand(query, conn);
//Replace #Name as parameter to avoid dependency injection
cmd.Parameters.Add("#Name", SqlDbType.VarChar);
cmd.Parameters["#name"].Value = "Michael";
try
{
conn.Open();
//Cast the return value to the string, if it's an integer then use (int)
accountNumber = (string)cmd.ExecuteScalar();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
Console.WriteLine(accountNumber);
//ReadKey just to keep the console from closing
Console.ReadKey();
}
}
}

If you are really new to C# with SQL Server, I would recommend to start from scratch using one of the tutorials shown here. It provides a lot of information in a step-by-step manner:
The basics
Clearly definition of the core ceoncepts
How to setup dependencies to get started
How to choose between development models (code, model vs. database first)
How to write queries
and much more.
Using SqlConnection is a valid choice, but requires more effort in writing the queries for doing basic stuff like selecting, updating, deleting or inserting data. You actually have to construct the queries and take care to build and dispose the commands.

On a related note:
The new way of doing all database-related activities in C# or .NET would be to harness Entity Framework (EF), and try to move away from any ADO.NET-based code. The latter still exists and hasn't been marked as obsolete, though. You may want to use ADO.NET for small apps or for any PoC tasks. But, otherwise, EF is the way to go.
EF is an ORM, and is indeed built as a repository pattern and generates a conceptual layer for us to work with. All of the nuances of the connection and command are completely encapsulated from us. This way, we don't have to meddle with these bare-bones.

If you want to do it well, you have to edit a file named Web.config in your project and put something like this inside (with your own DB data):
<connectionStrings >
<add
name="myConnectionString"
connectionString="Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;"
providerName="System.Data.SqlClient"/>
</connectionStrings>
Then, in the code, you can use it with:
SqlConnection con = new SqlConnection(
WebConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString);
Finally you can do that you want with "con", for example:
string queryString = "SELECT name, surname FROM employees";
SqlCommand command = new SqlCommand(queryString, con);
con.Open();
SqlDataReader reader = command.ExecuteReader();
try
{
while (reader.Read())
{
Console.WriteLine(String.Format("{0}, {1}",
reader["name"], reader["surname"]));
}
}
finally
{
reader.Close();
}

i use this nuget library.
https://www.nuget.org/packages/SqlServerDB_dotNET/
using SqlServerDB;
string server = #"INSTANCE\SQLEXPRESS";
string database = "DEMODB";
string username = "sa";
string password = "";
string connectionString = #"Data Source="+ server + ";Initial Catalog="+ database + "; Trusted_Connection=True;User ID="+ username + ";Password="+ password + "";
DBConnection db_conn = new DBConnection(connectionString);
Console.WriteLine("IsConnected: " + db_conn.IsConnected());
if (db_conn == null || !db_conn.IsConnected())
{
Console.WriteLine("Connessione non valida.");
return;
}
string sql = "SELECT ID, Message FROM Logs ORDER BY IDLic;";
DataTable dtLogs = db_conn.SelectTable(sql);
if (dtLogs == null || dtLogs.Rows.Count == 0)
return;
// Loop with the foreach keyword.
foreach (DataRow dr in dtLogs.Rows)
{
Console.WriteLine("Message: " + dr["Message"].ToString().Trim());
}

C# Asp.net can't connect to phpmyadmin

I am building an appliciation that connects with a database. Now the problem is that i get an error when i try to actually connect to the database. *note, I know its not save, its for testing purposes only.
Also, when i go to the url given in string server = "http://185.13.226.246:2222/CMD_DB/"; directly it will give me an error as in the picture below. But if I go to that URL indirectly (so via navigating) its fine.
It might be a very small problem but I can't find why it does not work.
edit: in the picture below there should be a list of available databases.
public class DataConnection
{
private static SqlConnection conn;
SqlCommand cmd = new SqlCommand();
public DataConnection() { }
public static SqlConnection Connection
{
get { return conn; }
}
public void ReadyConnection()
{
string server = "http://185.13.226.246:2222/CMD_DB/";
string database = "nickbbl114_atop";
string uid = "bbl114";
string password = "password010101";
string port = "2222";
string connectionString;
connectionString = "SERVER=" + server + ";" + "DATABASE=" +
database + ";" + "UID=" + uid + ";" + "PWD=" + password + ";";
conn = new SqlConnection(connectionString);
try
{
if (conn.State != ConnectionState.Open)
{
conn.Open();
}
}
catch (Exception ex)
{
throw ex;
}
}
public string Login(string email, string password)
{
string naam;
cmd.CommandText = "Select Voornaam From persoon where email = '" + email + "' and password = '" + password + "'";
cmd.CommandType = CommandType.Text;
cmd.Connection = conn;
ReadyConnection();
naam = cmd.ExecuteScalar().ToString();
return naam;
}
}

you can create same database for any type of application either it's in JAVA or Dotnet or PHP.It doesn't matter.
First try to create a service layer in asp.net for Database CRUD operations. 1) EmployeeService - API service. 1.Insert a new record in the table. 2.Delete the record. 3.Update the record.
Sample to create service layer using WCF service - http://www.codeproject.com/Articles/254714/Implement-CRUD-operations-using-RESTful-WCF-Servic
The above layer can be used for both asp.net and PHP.
2)Asp.Net application - Call the above service using Jquery from asp.net application
3)PHP application - Call the above service using jquery from asp.net application

Close MySQL Connection outside Function

I currently have a little app sends a lot of different MySQL Queries to the server. My idea was to wrap the connection, the query and the read to a function with only the actual query as a parameter.
Here is what I got:
public static MySqlDataReader mySqlRead(string cmdText)
{
string connString = "server=" + ORVars.sqlServerAddr + ";port=" + ORVars.sqlServerPort + ";uid=" + ORVars.sqlServerUID + ";pwd=" + ORVars.sqlServerPass + ";database=" + ORVars.sqlServerDB + ";";
MySqlConnection conn = new MySqlConnection(connString);
MySqlCommand command = conn.CreateCommand();
command.CommandText = cmdText;
try
{
conn.Open();
MySqlDataReader reader = command.ExecuteReader();
return reader;
}
catch (MySqlException)
{
throw;
}
}
I connect and send the query here:
private void btnLogin_Click(object sender, EventArgs e)
{
string username = txtLogin.Text;
string password = ORFunc.GetMD5Hash(txtPassword.Text);
MySqlDataReader orRead = ORFunc.mySqlRead("SELECT * FROM orUsers WHERE username = '" + username + "' AND pass = '" + password + "'");
while (orRead.Read())
{
MessageBox.Show(orRead["id"].ToString());
}
}
Works like a charm... BUT, as you can see above, the connection is never closed. When I add the conn.Close() behind the .ExecuteReader() the reader is empty and everything after return is of course useless.
Maybe it's a stupid question but I'm rather new to C# so please be generous, any hint is appreciated.
cheers,
PrimuS

I had a similar problem in JAVA recently, but I think the same will work for you. Essentially, you can create a class that represents a "SqlCall" object (or something). The class would have accessible members including the connection and the results. The ctor for the class would take in your query text.
Then, all you would have to do is create a new instance of that class, run the query in a method in that class (which would set and/or return the results), GET the results, and then when you are done, call close() on your class (which would then have to be coded such that it closes the connection held internally).
Technically, a better way to do this is to EXTEND the connection class itself, but as you are new to C#, I will not go into the details of doing so.
As I was writing the code below, I realized I may have not actually answered your question. But there's no point in backing out now, so here's what I have:
public class SqlCall {
private static connString = "server=" + ORVars.sqlServerAddr + ";port=" + ORVars.sqlServerPort + ";uid=" + ORVars.sqlServerUID + ";pwd=" + ORVars.sqlServerPass + ";database=" + ORVars.sqlServerDB + ";";
private MySqlConnection conn;
private MySqlCommand command;
private MySqlDataReader reader;
public SqlCall(String query) {
conn = new MySqlConnection(connString);
command = conn.CreateCommand();
command.CommandText = query;
}
public MySqlDataReader execute() throws Exception {
conn.Open();
reader = command.ExecuteReader();
return reader;
}
public void close() {
reader.close();
conn.close();
}
}
Your login code would be:
private void btnLogin_Click(object sender, EventArgs e) {
string username = txtLogin.Text;
string password = ORFunc.GetMD5Hash(txtPassword.Text);
SqlCall sqlcall = new SqlCall("SELECT * FROM orUsers WHERE username = '" + username + "' AND pass = '" + password + "'");
try {
MySqlDataReader orRead = sqlcall.execute();
while (orRead.Read())
{
MessageBox.Show(orRead["id"].ToString());
}
sqlcall.close();
} catch (Exception ex) {
// dostuff
}
}
The point is, unless you copy the data into a new datatable at the very beginning, you'll have to keep the connection open.
On a separate note, YOUR CODE IS PRONE TO SQL INJECTION. Don't know what that is? An example: if I said my username was ';DROP TABLE orUsers;--, then your entire user database would be gone. Look into stored procedures if you want a (very healthy) way around this.

You have difficulties because your idea works against the pattern expected by programs that connects to a database in NET Framework.
Usually, in this pattern you have a method that
INITIALIZE/OPEN/USE/CLOSE/DESTROY
the ADO.NET objects connected to the work required to extract or update data
Also your code has a serious problem called Sql Injection (see this famous explanation) because when you concatenate strings to form your command text you have no defense against a malicious user that try to attack your database
private void btnLogin_Click(object sender, EventArgs e)
{
string username = txtLogin.Text;
string password = ORFunc.GetMD5Hash(txtPassword.Text);
MySqlParameter p1 = new MySqlParameter("#uname", username);
MySqlParameter p2 = new MySqlParameter("#pass", pass);
string cmdText = "SELECT * FROM orUsers WHERE username = #uname AND pass = #pass"
DataTable dt = ORFunc.GetTable(cmdText, p1, p2);
foreach(DataRow r in dt.Rows)
{
Console.WriteLine(r["ID"].ToString());
}
}
public static DataTable GetTable(string cmdText, params MySqlParameter[] prms)
{
string connString = "server=" + ORVars.sqlServerAddr + ";port=" + ORVars.sqlServerPort + ";uid=" + ORVars.sqlServerUID + ";pwd=" + ORVars.sqlServerPass + ";database=" + ORVars.sqlServerDB + ";";
// This is the INITIALIZE part
using(MySqlConnection conn = new MySqlConnection(connString))
using(MySqlCommand command = new MySqlCommand(cmdText, conn))
{
// OPEN
conn.Open();
DataTable dt = new DataTable();
command.Parameters.AddRange(prms);
// USE
MySqlDataReader reader = command.ExecuteReader();
dt.Load(reader);
return dt;
} // The closing brace of the using statement is the CLOSE/DESTROY part of the pattern
}
Of course this is a generic example and in my real work I don't use very often these generic methods and prefer to write specialized data access code that return the base object needed to the upper layer of code

Code to create & connect to a SQL Server database: Whats wrong with it?

I am new to C# & I am trying to programatically create & open a SQL Server database.
I have a ASP.NET webapp I am creating & on page load it should pull some data from the database (if the db doesn't exist, it should be created & populated with default data).
PS: does C#'s System.Data.SqlClient use MySQL or SQLite or something else?
Right now I am unsure if my code correctly creates a SQL Server database & if I connect to it correctly.
Can you tell me if my code is correct & how I could improve it?
UPDATE: Error is
"A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible. Verify that the instance name is correct and that
SQL Server is configured to allow remote connections. (provider: Named
Pipes Provider, error: 40 - Could not open a connection to SQL
Server)"}"
I have indicated where in the code below the error occurs.
Creating a SQL Server database:
// When I run this function no file seems to be created in my project directory?
// Although there is a ASPNETDB sql database file in my App_Data folder so this maybe it
public static string DEF_DB_NAME = "mydb.db"; // is this the correct extension?
private bool populateDbDefData()
{
bool res = false;
SqlConnection myConn = new SqlConnection("Server=localhost;Integrated security=SSPI;database=master");
string str = "CREATE DATABASE "+DEF_DB_NAME+" ON PRIMARY " +
"(NAME = " + DEF_DB_NAME + "_Data, " +
"FILENAME = " + DEF_DB_NAME + ".mdf', " +
"SIZE = 2MB, MAXSIZE = 10MB, FILEGROWTH = 10%) " +
"LOG ON (NAME = " + DEF_DB_NAME + "_Log, " +
"FILENAME = " + DEF_DB_NAME + "Log.ldf', " +
"SIZE = 1MB, " +
"MAXSIZE = 5MB, " +
"FILEGROWTH = 10%)";
SqlCommand myCommand = new SqlCommand(str, myConn);
try
{
myConn.Open(); // ERROR OCCURS HERE
myCommand.ExecuteNonQuery();
insertDefData(myConn);
}
catch (System.Exception ex)
{
res = false;
}
finally
{
if (myConn.State == ConnectionState.Open)
myConn.Close();
res = true;
}
return res;
}
Here's my connection to the SQL Server database code: I am pretty sure it fails to connect - if I try to use the variable conn, it says the connection is not open. Which could mean that I either failed to connect or failed to even create the db in the 1st place:
private bool connect()
{
bool res = false;
try
{
conn = new SqlConnection("user id=username;" +
"password=password;" +
"Server=localhost;" +
"Trusted_Connection=yes;" +
"database="+DEF_DB_NAME+"; " +
"connection timeout=30");
conn.Open();
return true;
}
catch (Exception e)
{
}
return false;
}

You have probably already got this figured out, but just in case people end up here with the same problem (like I did) here's how I got this working.
Your error is that the SqlConnection is not being opened, because it isn't finding an appropriate server. If you're using the SQL server express edition (as I am) you should set the SqlConnection object like this:
SqlConnection myConn = new SqlConnection("Server=localhost\\SQLEXPRESS;Integrated security=SSPI;database=master;");
Once you resolve that error though, you are going to fail on the next line when you try to execute the query. The "Filename" needs to be separated by single quotes, but you only have one on the end after the extension; you will also need one before.
Also, that is the full physical file path, and it won't use the current directory context, you have to specify a path. Make sure that the location is one which the db server will have access to when it's running, otherwise you will get a SqlException being thrown with an error message along the lines of:
Directory lookup for the file "...\filename.mdf" failed with the operating system error 5 (Access is denied). CREATE DATABASE failed. Some file names listed could not be created.
The code which I ended up using looks like this:
public static string DB_NAME = "mydb"; //you don't need an extension here, this is the db name not a filename
public static string DB_PATH = "C:\\data\\";
public bool CreateDatabase()
{
bool stat=true;
string sqlCreateDBQuery;
SqlConnection myConn = new SqlConnection("Server=localhost\\SQLEXPRESS;Integrated security=SSPI;database=master;");
sqlCreateDBQuery = " CREATE DATABASE "
+ DB_NAME
+ " ON PRIMARY "
+ " (NAME = " + DB_NAME + "_Data, "
+ " FILENAME = '" + DB_PATH + DB_NAME + ".mdf', "
+ " SIZE = 2MB,"
+ " FILEGROWTH = 10%) "
+ " LOG ON (NAME =" + DB_NAME + "_Log, "
+ " FILENAME = '" + DB_PATH + DB_NAME + "Log.ldf', "
+ " SIZE = 1MB, "
+ " FILEGROWTH = 10%) ";
SqlCommand myCommand = new SqlCommand(sqlCreateDBQuery, myConn);
try
{
myConn.Open();
myCommand.ExecuteNonQuery();
}
catch (System.Exception)
{
stat=false;
}
finally
{
if (myConn.State == ConnectionState.Open)
{
myConn.Close();
}
myConn.Dispose();
}
return stat;
}

Use this code,
internal class CommonData
{
private static SqlConnection conn;
public static SqlConnection Connection
{
get { return conn; }
}
public static void ReadyConnection()
{
conn = new SqlConnection();
conn.ConnectionString = ConfigurationManager.ConnectionStrings["DBConnectionString"].ToString();
if (conn.State != ConnectionState.Open)
{
conn.Open();
}
}
public static int ExecuteNonQuery(SqlCommand command)
{
try
{
ReadyConnection();
command.Connection = conn;
int result = command.ExecuteNonQuery();
return result;
}
catch (Exception ex)
{
throw ex;
}
finally
{
command.Dispose();
if (conn.State == ConnectionState.Open) conn.Close();
conn.Dispose();
}
}
public static SqlDataReader ExecuteReader(SqlCommand command)
{
try
{
ReadyConnection();
command.Connection = conn;
SqlDataReader result = command.ExecuteReader(CommandBehavior.CloseConnection);
return result;
}
catch (Exception Ex)
{
throw Ex;
}
}
public static object ExecuteScalar(SqlCommand command)
{
try
{
ReadyConnection();
command.Connection = conn;
object value = command.ExecuteScalar();
if (value is DBNull)
{
return default(decimal);
}
else
{
return value;
}
}
catch (Exception ex)
{
throw ex;
}
}
public static void ClearPool()
{
SqlConnection.ClearAllPools();
}
}

PS: does C#'s System.Data.SqlClient use MySQL or SQLite or something else?
MySQL provides their own C# dll for connecting to their database, as do the majority of other database manufacturers. I recommend using theirs. I typically using the built-in SQL client for MS SQL (I am not aware if it can be used with other DBs).
As for this line: insertDefData(myConn) -> the method is not included in your code sample.
As for SQL debugging in general, use the GUI for debugging. I know a lot of people who grew up on MySQL do not want to, or do not understand why you should use one, but it's really a good idea. If you are connecting to MySQL, I recommend MySQL WorkBench CE; if you are connecting to a MS database, SQL Management Studio is what you want. For others, GUIs should be available. The idea here is that you can selectively highlight sections of your query and run it, something not available via command-line. You can have several queries, and only highlight the ones you want to run. Plus, exploring the RDBMS is easier via a GUI.
And if you want to prevent a SQL injection attack, just Base64 encode the string data going in.
As for the connection string itself, we will need some more data on what type of database, exactly, you are trying to connect to. Personally, I recommend just creating a separate SQL account to handle operations (easier to track, and you only need to give it permissions to what you want it to access; security and all that).