Just how do I connect to a database and also loop over a recordset in C#?

What's the most basic means to connect and also quiz a database for a set of documents in C#?

0
2019-05-03 17:58:41
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Answers: 4

This is a different means (DataReader is much faster than this set):

string s = "";
SqlConnection conn = new SqlConnection("Server=192.168.1.1;Database=master;Connect Timeout=30;User ID=foobar;Password=raboof;");
SqlDataAdapter da = new SqlDataAdapter("SELECT TOP 5 name, dbid FROM sysdatabases", conn);
DataTable dt = new DataTable();

da.Fill(dt);

for (int i = 0; i < dt.Rows.Count; i++)
{
    s += dt.Rows[i]["name"].ToString() + " -- " + dt.Rows[i]["dbid"].ToString() + "\n";
}

MessageBox.Show(s);
0
2019-05-12 10:50:09
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That's most definitely an excellent way to do it. Yet you if you take place to be making use of a database that sustains LINQ to SQL, it can be a whole lot extra enjoyable. It can look something similar to this :

MyDB db = new MyDB("Data Source=...");
var q = from db.MyTable
        select c;
foreach (var c in q)
  Console.WriteLine(c.MyField.ToString());
0
2019-05-08 21:39:40
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@Goyuix-- that's superb for something created from memory. examined it below-- located the connection had not been opened up. Or else really wonderful.

using System.Data.OleDb;
...

using (OleDbConnection conn = new OleDbConnection())
{
    conn.ConnectionString = "Provider=sqloledb;Data Source=yourServername\\yourInstance;Initial Catalog=databaseName;Integrated Security=SSPI;";

    using (OleDbCommand cmd = new OleDbCommand())
    {
        conn.Open();
        cmd.Connection = conn;
        cmd.CommandText = "Select * from yourTable";

        using (OleDbDataReader dr = cmd.ExecuteReader())
        {
            while (dr.Read())
            {
                Console.WriteLine(dr["columnName"]);
            }
        }
    }
}
0
2019-05-07 16:47:18
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Very about and also from memory given that I do not have code on this laptop computer :

using (OleDBConnection conn = new OleDbConnection())
{
  conn.ConnectionString = "Whatever connection string";

  using (OleDbCommand cmd = new OleDbCommand())
  {
    cmd.Connection = conn;
    cmd.CommandText = "Select * from CoolTable";

    using (OleDbDataReader dr = cmd.ExecuteReader())
    {
      while (dr.Read())
      {
        // do something like Console.WriteLine(dr["column name"] as String);
      }
    }
  }
}
.
0
2019-05-07 16:46:17
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