I am creating a program in which I am trying to have a new database connection in an existing database connection in OLEDB using ASP.net. Is that even possible?
"Connection within connection" is likely not what you have in mind. But there is no issue with having both OleDb and SQLServer connections operating together in one ASP.NET application, you can add these 2 or many more connections to one app.
Answer is yes. Please make sure you close the connections after using by using statement or close() explicitly. More here.
using (OleDbConnection connection1 = new OleDbConnection(connectionString1))
using (OleDbConnection connection2 = new OleDbConnection(connectionString2))
{
connection1.Open();
connection2.Open();
// Do something
}
Related
I am new to uploading websites online, I have uploaded my website to Godaddy host and run perfectly but i don't know how to connect my MS Sql Data base and how to configure my connection string ! can any one help me or give me a tutorial of how doing this starting from a normal MS sql Database with normal connection string(Local DB and Local connection string) until uploading it online ?
Connecting to a sql server database on go daddy works the same way as connecting to any other Sql Server db from a .Net perspective.
Log in to your go daddy account to get the connection string info. There's even code samples in there for how to configure your connection string.
Alos, here's a link about .net connection strings in general
http://msdn.microsoft.com/en-us/library/jj653752(v=vs.110).aspx
One of the advantages of using MS SQL is that you can use the SqlClient native libraries, which are faster than ODBC, etc.
using System.Data;
using System.Data.SqlClient;
public class Demo {
public DataTable ConnectAndQuery() {
SqlConnection cn = new SqlConnection("Data Source=IP-GOES-HERE;Initial Catalog=YOUR-DATABASE-NAME-HERE;user id=DB-USER-HERE;password=DB-PASS-HERE;Connection Timeout=300");
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM TableName", cn);
DataSet results = new DataSet();
da.Fill(results);
return results;
}
}
I usually store my connection strings in the web.config. There's actually a specific section you can store them in, if you'd like. Here's an example of that:
http://msdn.microsoft.com/en-us/library/dx0f3cf2(v=vs.85).aspx
It's my first time of using MySql on ASP.Net.
Unlike MSSql which I use quite often, I've noticed that using MySqlConnection to connect to the db takes ages (I mean a second or two),
MySql.Data.MySqlClient.MySqlConnection connection = new MySqlConnection(DBConnectionString);
Therefore I would like to know how can I implement a connection pool, or whatever recommended structure that could store one connection object (MySqlConnection) to be used across the application.
Is there a common practice for doing so or any other recommendations ?
Here's the code I'm using - maybe I'm doing something wrong here ?
MySql.Data.MySqlClient.MySqlConnection connection = new MySqlConnection(DBConnectionString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
if (connection.State != ConnectionState.Open)
{
try
{
connection.Open();
}
catch (MySqlException ex)
{
throw (ex);
}
}
MySqlCommand cmd = new MySqlCommand("SELECT this FROM that", connection);
DataSet ds = new DataSet();
adapter.SelectCommand = cmd;
adapter.Fill(ds);
cmd.Connection.Close();
According to the documentation it's on by default. Further, you're creating the instance with the connection string, so that's good, because it allows the connector to leverage the pool immediately. So, the fact that it's taking a second or two to create those connections is almost certainly unrelated to connection pooling and more related to the hardware you're providing MySQL in the environment you're working in.
The term hardware is really broad here because you could be dealing with everything from network to disk and memory related issues.
Do read the documentation - it does show you how to adjust the connection pooling - so that may help you. I make that statement because your question doesn't give us a lot of information surrounding exactly how you're using this server or these connections.
I am looking to port my very basic DBMS software from classic ASP to ASP.net - however the user would need to input the connection details in order to connect to their specific DBMS server.
Is this at all possible with ASP.NET MVC (very similar to DSN-less connections in ASP).
Cheers,
Joel
The question should really be "is this possible with .NET", ASP.NET MVC is not a database technology, and DSN-less connections aren't ASP technology either. In .NET, it is the ADO.NET framework that allows you to access database resources, and it can be used from any .NET code, be it desktop, web and mobile too.
There are some specialised libraries for certain platforms, .NET includes native support for Sql Server, you can get the MySql Connector for .NET, etc.
All of these providers are built around the ADO.NET provider model, you can either use them explicitly, or you can use the provider-agnostic method. Here are two examples, the first being Sql Server:
string connectionString = "Server=....";
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand command = new SqlCommand("SELECT [Name] FROM [People]"))
{
connection.Open();
using (SqlDataReader reader = command.ExecuteReader())
{
// Do something here.
}
}
}
In the above example, I'm using the specific Sql Server ADO.NET types to create a connection to a database and execute an arbitrary query against it.
If you are intended to support multiple database platforms, it's probably best to design your code such that it can utilise the ADO.NET Factory classes which are specialised factories geared to the creation of platform specific types. In the example below, I've used the Factory classes to access a MySql Server database:
string connectionString = "Server=....";
DbProviderFactory factory = DbProviderFactories.GetFactory("MySql.Data");
using (DbConnection connection = factory.CreateConnection())
{
connection.ConnectionString = connectionString;
using (DbCommand command = factory.CreateCommand())
{
command.CommandText = "SELECT `Name` FROM Page";
connection.Open();
using (DbDataReader reader = command.ExecuteReader())
{
// Do something here.
}
}
}
Not the perfect example, but enough to get you going, but it's important to remember that DSN-less connections are not tied to ASP or ASP.NET.
Hope that helps.
I'm trying to rename my SQLite database file after I'm done using it, however the file still appears to be opened by SQLite even after all my connections are closed.
Here is an example of what I'm doing:
using (DbConnection conn = new SQLiteConnection("Data Source=test.db"))
{
conn.Open();
DbCommand command = conn.CreateCommand();
command.CommandText = "select id from test";
command.ExecuteScalar();
}
File.Move("test.db", "test.db.test");
The Move call throws an IOException. This is the only connection that I have to this database file. Once the application ends I can move the file manually without a problem. I've tried various things such as explicitly setting Pooling=false in the connection string, manually calling Close before the connection is disposed, explicitly starting and committing a transaction, but none of this seems to help. Is there a way to force SQLite to close/release the database file without exiting the application?
I presume you are using SQLite.Net? I have just tried your code and works without problem with SQLite.Net 1.0.65, in VS 2005 on Vista.
DBCommand is IDisposable. Maybe you need to call Dispose on it or create it in a using statement.
I'm designing a web service in ASP.NET and VS2008, and am using typed datasets for retrieving table data. These work well and establish their own connections through their associated TableAdapter objects. Edit: I'm using VB, BTW!
I am now attempting to run a custom SQL string using a DataAdapter and a Command object, however I need to reference a Connection object in order for the Command to work. What is the best way to handle this? Should I:
a) Create a global connection object using Global.asax, retrieving the connection string from web.config? (I've been trying that one already, with not much success)
b) Create a class-level connection object using the InitialiseComponent method, also retrieving the ConnectionString from web.config?
c) Retrieve a Connection from one of the TableAdapters that I've already created in my typed DataSets?
d) Something else I haven't thought of yet?
BTW I've been finding it very difficult to extract a ConnectionString from web.config, so any help with that would be appreciated also!
I'm not entirely inexperienced with ASP.NET, but my last big project used VS2003, and I want to make sure that I'm using the current tools correctly.
To extract the connection string, use
WebConfigurationManager.ConnectionStrings["name"].ConnectionString
It's best to open and close the connections as close as possible to their use. ADO.NET will do connection pooling so that this won't be expensive:
var connectionString =
WebConfigurationManager.ConnectionStrings["name"].ConnectionString;
using (SqlConnection conn = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand("query", conn))
{
conn.Open();
// Use the command
}
}
For Connection and data access problems I will advise you to go with some kind of Data Helpers like Microsoft Data Access Application Block
Here you can find small tutorial about how to use it.
For getting connectionstring from web.config use folowing methods
public static string GetConnectionString( string strConstringKey )
{
return ConfigurationManager.ConnectionStrings[strConstringKey];
}
public static bool GetConnectionString(string strConstringKey, ref string strConstring)
{
return (strConstring = ConfigurationManager.ConnectionStrings[strConstringKey] ) == null ? false : true ;
}