Providers factory provides us indepandent database access where we can connect to any database sources(SQLServer,DB2,Oracle,MS-Access).
Provider Factory allows programmers to write their own implementation for accessing database.
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.Common;
namespace DatabaseProvider
{
/// <summary>
///
/// Design Pattern: Factory.
/// </summary>
public abstract class Database
{
private string connectionString;
private DbProviderFactory dbProviderFactory;
private string schema;
private string dataProvider;
private bool status;
protected Database() { }
public DbProviderFactory DbProviderFactory
{
get { return dbProviderFactory; }
}
public string ConnectionString
{
get { return connectionString; }
set { connectionString = value; }
}
public string Schema
{
get { return schema; }
}
public string DataProvider
{
get { return dataProvider; }
}
public DbConnection GetConnection()
{
DbConnection newConnection = null;
try
{
try
{
ProviderFactory = DbProviderFactories.GetFactory(this.ProviderType);
dbConnection = ProviderFactory.CreateConnection();
dbConnection.ConnectionString = this.ConnectionString;
}
catch
{
throw;
}
}
catch
{
if (newConnection != null)
newConnection.Close();
throw;
}
return newConnection;
}
public DbCommand CreateCommand()
{
return dbProviderFactory.CreateCommand();
}
public DbCommand CreateCommand(string sQueryString, DbConnection connection)
{
try
{
// Create the DbCommand.
DbCommand command = this.CreateCommand();
command.CommandText = sQueryString;
command.Connection = connection;
return command;
}
catch
{
throw;
}
}
public DbDataAdapter CreateDataAdapter()
{
return dbProviderFactory.CreateDataAdapter();
}
public DbDataAdapter CreateDataAdapter(string sQueryString, DbConnection connection)
{
try
{
// Create the DbCommand.
DbCommand command = this.CreateCommand();
command.CommandText = sQueryString;
command.Connection = connection;
// Create the DbDataAdapter.
DbDataAdapter adapter = this.CreateDataAdapter();
adapter.SelectCommand = command;
return adapter;
}
catch
{
throw;
}
}
private DbCommandBuilder CreateCommandBuilder()
{
return dbProviderFactory.CreateCommandBuilder();
}
public DbCommandBuilder CreateCommandBuilder(DbDataAdapter dbDA)
{
DbCommandBuilder dbCB = this.CreateCommandBuilder();
dbCB.DataAdapter = dbDA;
return dbCB;
}
}
}
web.config
<add key="Connectionstring" value="database=local;user id=sa;pwd=sa;initial catalog=northwind"/>
<add key="SQLProvider" value="System.Data.SqlClient"/>
<add key="OledbProvider" value="System.Data.OleDb"/>
<add key="Db2Provider" value="IBM.Data.DB2"/>
<add key="OracleProvider" value="System.Data.OracleClient"/>
aspx.cs
private Database DB;
private DbDataAdapter SQLDA;
private DbCommandBuilder SQLDB;
private DbConnection Conn;
private DBCommand cmd;
//pass the connection string and provider type to create database connection
DB.Connectionstring=Configuration.ConfigurationManager.AppSettings["Connectionstring"].ToString();
DB.DataProvider=Configuration.ConfigurationManager.AppSettings["SQLProvider"].ToString();
//create database connection
Conn = DB.GetConnection();
Conn.Open();
//creating Data Adapter
SQLDA=DB.CreateDataAdapter("select * from emp",Conn);
//Create Command Builder
SQLDB=DB.CreateCommandBuilder(SQLDA);
//Create Command
cmd=DB.CreateCommand("select * from emp",Conn);
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