в 15:31, 26 мая 2010

2010-05-26T15:31:19Z

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2010-05-26T11:42:25Z

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==Geting Table column data type==

<source lang="csharp">
using System;
using System.Data;
using System.Data.OleDb;
public class DatabaseInfo {
public static void Main () {
String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.\\Employee.mdb";
OleDbConnection con = new OleDbConnection(connect);
con.Open();
Console.WriteLine("Made the connection to the database");
Console.WriteLine("Information for each table contains:");
DataTable tables = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables,new object[]{null,null,null,"TABLE"});
foreach(DataColumn col in tables.Columns)
Console.WriteLine("{0}\t{1}", col.ColumnName, col.DataType);
con.Close();
}
}

</source>

==Read column values as C# types using the "Get" methods==

<source lang="csharp">
using System;
using System.Data;
using System.Data.SqlClient;
class StronglyTypedColumnValues
{
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText = "SELECT TOP 5 ProductID, ProductName, UnitPrice, " +
"UnitsInStock, Discontinued " +
"FROM Products " +
"ORDER BY ProductID";
mySqlConnection.Open();
SqlDataReader productsSqlDataReader = mySqlCommand.ExecuteReader();
int productIDColPos = productsSqlDataReader.GetOrdinal("ProductID");
int productNameColPos = productsSqlDataReader.GetOrdinal("ProductName");
int unitPriceColPos = productsSqlDataReader.GetOrdinal("UnitPrice");
int unitsInStockColPos = productsSqlDataReader.GetOrdinal("UnitsInStock");
int discontinuedColPos = productsSqlDataReader.GetOrdinal("Discontinued");
Console.WriteLine("ProductID .NET type = " + productsSqlDataReader.GetFieldType(productIDColPos));
Console.WriteLine("ProductName .NET type = " + productsSqlDataReader.GetFieldType(productNameColPos));
Console.WriteLine("UnitPrice .NET type = " + productsSqlDataReader.GetFieldType(unitPriceColPos));
Console.WriteLine("UnitsInStock .NET type = " + productsSqlDataReader.GetFieldType(unitsInStockColPos));
Console.WriteLine("Discontinued .NET type = " + productsSqlDataReader.GetFieldType(discontinuedColPos));
Console.WriteLine("ProductID database type = " + productsSqlDataReader.GetDataTypeName(productIDColPos));
Console.WriteLine("ProductName database type = " + productsSqlDataReader.GetDataTypeName(productNameColPos));
Console.WriteLine("UnitPrice database type = " + productsSqlDataReader.GetDataTypeName(unitPriceColPos));
Console.WriteLine("UnitsInStock database type = " + productsSqlDataReader.GetDataTypeName(unitsInStockColPos));
Console.WriteLine("Discontinued database type = " + productsSqlDataReader.GetDataTypeName(discontinuedColPos));
while (productsSqlDataReader.Read())
{
int productID = productsSqlDataReader.GetInt32(productIDColPos);
Console.WriteLine("productID = " + productID);
string productName = productsSqlDataReader.GetString(productNameColPos);
Console.WriteLine("productName = " + productName);
decimal unitPrice = productsSqlDataReader.GetDecimal(unitPriceColPos);
Console.WriteLine("unitPrice = " + unitPrice);
short unitsInStock = productsSqlDataReader.GetInt16(unitsInStockColPos);
Console.WriteLine("unitsInStock = " + unitsInStock);
bool discontinued = productsSqlDataReader.GetBoolean(discontinuedColPos);
Console.WriteLine("discontinued = " + discontinued);
}
productsSqlDataReader.Close();
mySqlConnection.Close();
}
}

</source>

==Read column values as Sql* types using the GetSql* methods==



<source lang="csharp">

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
class StronglyTypedColumnValuesSql
{
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"SELECT TOP 5 ID, Name, UnitPrice, " +
"UnitsInStock, Discontinued " +
"FROM Products " +
"ORDER BY ProductID";
mySqlConnection.Open();
SqlDataReader productsSqlDataReader = mySqlCommand.ExecuteReader();
int productIDColPos = productsSqlDataReader.GetOrdinal("ID");
int productNameColPos = productsSqlDataReader.GetOrdinal("Name");
int unitPriceColPos = productsSqlDataReader.GetOrdinal("UnitPrice");
int unitsInStockColPos = productsSqlDataReader.GetOrdinal("UnitsInStock");
int discontinuedColPos = productsSqlDataReader.GetOrdinal("Discontinued");
while (productsSqlDataReader.Read())
{
SqlInt32 productID = productsSqlDataReader.GetSqlInt32(productIDColPos);
Console.WriteLine("productID = " + productID);
SqlString productName = productsSqlDataReader.GetSqlString(productNameColPos);
Console.WriteLine("productName = " + productName);
SqlMoney unitPrice = productsSqlDataReader.GetSqlMoney(unitPriceColPos);
Console.WriteLine("unitPrice = " + unitPrice);
SqlInt16 unitsInStock = productsSqlDataReader.GetSqlInt16(unitsInStockColPos);
Console.WriteLine("unitsInStock = " + unitsInStock);
SqlBoolean discontinued = productsSqlDataReader.GetSqlBoolean(discontinuedColPos);
Console.WriteLine("discontinued = " + discontinued);
}
productsSqlDataReader.Close();
mySqlConnection.Close();
}
}

</source>

==Refernece column name in SqlDataReader==

<source lang="csharp">
using System;
using System.Data.SqlClient;
class FirstExample
{
public static void Main()
{
try
{
SqlConnection mySqlConnection = new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI");
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText = "SELECT id, firstname, lastname from employee";
mySqlConnection.Open();
SqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader();
mySqlDataReader.Read();
Console.WriteLine("mySqlDataReader[\" ID\"] = "+ mySqlDataReader["ID"]);
Console.WriteLine("mySqlDataReader[\" First Name\"] = "+ mySqlDataReader["FirstName"]);
Console.WriteLine("mySqlDataReader[\" Last Name\"] = "+ mySqlDataReader["LastName"]);
mySqlDataReader.Close();
mySqlConnection.Close();
}
catch (SqlException e)
{
Console.WriteLine("A SqlException was thrown");
Console.WriteLine("Number = "+ e.Number);
Console.WriteLine("Message = "+ e.Message);
Console.WriteLine("StackTrace:\n" + e.StackTrace);
}
}
}

</source>

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Csharp/C Sharp/Database ADO.net/Table Column - История изменений

в 15:31, 26 мая 2010

Admin: 1 версия