Original link: https: //blog.csdn.net/zhang_hui_cs/article/details/7327395
using System.Data;
using System.Data.SqlClient;
// SqlDataAdapter MSDN Web site: http: //msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldataadapter.aspx
// DataTable MSDN Web site: http: //msdn.microsoft.com/en-us/library/system.data.datatable.aspx
// DataSet MSDN Web site: http://msdn.microsoft.com/en-us/library/system.data.dataset.aspx
//DataSets, DataTables, and DataViews (ADO.NET)： http://msdn.microsoft.com/en-us/library/ss7fbaez.aspx
namespace Chapter13
{
class FilterSort
{
static void Main(string[] args)
{
// connection string
string connString = @"
server = .;
integrated security = true;
database = northwind
";
// query 1
string sql1 = @" select * from customers ; ";
// query 2
string sql2 = @" select * from products where unitprice < 10 ";
// combine queries
string sql = sql1 + sql2;
// create connection
SqlConnection conn = null;
try
{
conn = new SqlConnection(connString);
// create data adapter
SqlDataAdapter da = new SqlDataAdapter(sql, conn);
// create and fill data set
DataSet ds = new DataSet();
/*
* If the sql statement SqlDataAdapter corresponding return a plurality of data sets ,
* The SqlDataAdapter corresponding DataTable name
* Will be named sequentially as "Table", "Table1", "Table2" ......
* The following call will get the "Table" corresponds to the "Customers",
* "Table1" corresponds to the "Products"
*/
da.TableMappings.Add("Table", "Customers");
da.TableMappings.Add("Table1", "Products");
da.Fill(ds);
// get the data tables collection
DataTableCollection dtc = ds.Tables;
// output DataTableCollection table name in all tables.
System.Console.WriteLine("DataTable in the DataTableCollection: ");
foreach (DataTable dt in dtc)
{
System.Console.WriteLine("\t{0}", dt.ToString());
}
// display data from first data table
//
// display output header
System.Console.WriteLine("Results from Customers table:");
System.Console.WriteLine(
"CompanyName".PadRight(20) +
"ContactName".PadLeft(23) + "\n");
// set display filter
string fl = "country = 'Germany'";
// set sort
string srt = "companyname asc";
foreach (in the DataRow Row dtc [ "the Customers"]. the Select (FL, srt) ) // dtc [ "the Customers"] is a DataTable, look for the memory of a database table, ordering inquiry in accordance with the conditions +
{
System.Console.WriteLine(
"{0}\t{1}",
row["CompanyName"].ToString().PadRight(25),
row["ContactName"]);
}
// display data from second data table
//
// display output header
System.Console.WriteLine("\n----------------------------");
System.Console.WriteLine("Results from Products table:");
System.Console.WriteLine(
"ProductName".PadRight(20) +
"UnitPrice".PadLeft(21) + "\n");
// next sentence dtc [ "Products"] may also be in accordance with the table index value to access, equivalent to dtc [1]
foreach (DataRow row in dtc["Products"].Rows)
{
System.Console.WriteLine("{0}\t{1}",
row["productname"].ToString().PadRight(25),
row["unitprice"]);
}
}
catch (System.Exception e)
{
System.Console.WriteLine("Error: " + e);
}
finally
{
// close connection
conn.Close();
}
}
}
}