Querying with the DataReader
The CData ADO.NET Provider for Snowflake implements two ADO.NET interfaces you can use to retrieve data from Snowflake: SnowflakeDataAdapter and SnowflakeDataReader objects. Whereas SnowflakeDataAdapter objects retrieve a single result set of all the data that matches a query, SnowflakeDataReader objects fetch data in subset increments as needed.
Using the SnowflakeDataReader
The SnowflakeDataReader retrieves data faster than the SnowflakeDataAdapter because it can retrieve data in pages. As you read data from the SnowflakeDataReader, it periodically requests the next page of results from the data source, if required. This causes results to be returned at a faster rate. The following example selects all the columns from the [DemoDB].[PUBLIC].Products table:
C#
string connectionString = "url=https://myaccount.region.snowflakecomputing.com;user=Admin;password=test123;Database=Northwind;Warehouse=TestWarehouse;Account=Tester1;"; using (SnowflakeConnection connection = new SnowflakeConnection(connectionString)) { SnowflakeCommand cmd = new SnowflakeCommand("SELECT * FROM [DemoDB].[PUBLIC].Products", connection); SnowflakeDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["Id"], rdr["ProductName"])); } }
VB.NET
Dim connectionString As String = "url=https://myaccount.region.snowflakecomputing.com;user=Admin;password=test123;Database=Northwind;Warehouse=TestWarehouse;Account=Tester1;" Using connection As New SnowflakeConnection(connectionString) Dim cmd As New SnowflakeCommand("SELECT * FROM [DemoDB].[PUBLIC].Products", connection) Dim rdr As SnowflakeDataReader = cmd.ExecuteReader() While rdr.Read() Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Id"), rdr("ProductName"))) End While End Using