Is System.Data.SqlClient code managed code?

Question

Are the queries executed in a C# progamm using System.Data.SqlClient namespace cosnidered managed or umanaged code?
Every time the connection is closed , (conn.Close() method is used) does the resource consider released or we have to dispose it in order to get released?

The queries are executed on SQL Server or whatever other database system you connect to - and those systems typically aren't managed code bases... — marc_s, Apr 10 '13 at 16:13
Are you asking this out of curiosity or because you have a specific problem that you need this information for? If you do have a problem, it would be best to describe it directly. — Pondlife, Apr 10 '13 at 16:28
@Pondlife I have a project in C# were I am opening multiples times sql conn's. I want to Know if every time I close the conn the resources are relseased or alternatively I have to use Dispose method. Moreover I ask Q1 in case I need to implement my own dispose method for releasing resources after every query. — apomene, Apr 10 '13 at 16:32
According to .NET guidelines Close and Dispose should be equivalent and Close is used when it is semantically correct while Dispose is more general term used by IDisposable. — Stilgar, Apr 10 '13 at 16:40

KF2 · Answer 1 · 2013-04-10T16:40:08.600

About second question:

The Close method rolls back any pending transactions. It then releases the connection to the connection pool, or closes the connection if connection pooling is disabled.

Edited

The following example creates a SqlConnection, opens it, displays some of its properties. The connection is automatically closed at the end of the using block.

private static void OpenSqlConnection(string connectionString)
{
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();
        Console.WriteLine("ServerVersion: {0}", connection.ServerVersion);
        Console.WriteLine("State: {0}", connection.State);
    }
}

Edited

You need a using for every object you create that implements IDisposable. That includes the SqlCommand and the SqlConnection.If you use using statement, they will dispose after using block.

score 1 · Accepted Answer · answered Apr 10 '13 at 16:37

System.Data.SqlClient itself is managed code. However, it is built on top of several other libraries. Some of them are managed code and some are not.

The query itself is executed by a database. So, the text of the query (the part that is hard-coded in your program) would be considered managed code, but once the command is sent to a database, it is no-longer managed.
Once the .close command is executed, the connection itself is released from your .net app and returned to the connection pool (part of OLEDB, ODBC and/or other sub-systems). At that point, the connection is freed and the unmanaged part is released. Dispose will do everything close does and release other managed parts (connection string, etc).

It is always a good idea to call dispose on any object that implements it (or wrap it in a using block, like @IRSOG showed). In this case, it isn't particularly dangerous to just call close(). I wouldn't make a habit of it.

Is System.Data.SqlClient code managed code?

2 Answers2