数据层抽象工厂 [英] Data Layer Abstract Factory

问题描述

我是开发抽象工厂模式的新手，并且想在数据层中创建一个抽象工厂，这将帮助我将该层链接到其他任何数据库，例如sql和oracle.您能帮我完成这项任务吗?请注意，数据库的连接字符串将在此层而不是表示中找到.

I'm new on developing an Abstract Factory pattern, and would like to create an abstract factory in the data layer that will help me link this layer to any other databases for example sql and oracle. Can you help me on developing this task please. Note that the connection string of the database will be found in this layer not in the presentation..

谢谢

已编辑

public abstract class Database
{
    public string connectionString;

    #region Abstract Functions

    public abstract IDbConnection CreateConnection();
    public abstract IDbCommand CreateCommand();
    public abstract IDbConnection CreateOpenConnection();
    public abstract IDbCommand CreateCommand(string commandText, IDbConnection connection);
    public abstract IDbCommand CreateStoredProcCommand(string procName, IDbConnection connection);
    public abstract IDataParameter CreateParameter(string parameterName, object parameterValue);

    #endregion
}

---

public class SQLDatabase : Database
{
    public override IDbConnection CreateConnection()
    {
        return new SqlConnection(connectionString);
    }

    public override IDbCommand CreateCommand()
    {
        return new SqlCommand();
    }

    public override IDbConnection CreateOpenConnection()
    {
        SqlConnection connection = (SqlConnection)CreateConnection();
        connection.Open();

        return connection;
    }

    public override IDbCommand CreateCommand(string commandText, IDbConnection connection)
    {
        SqlCommand command = (SqlCommand)CreateCommand();

        command.CommandText = commandText;
        command.Connection = (SqlConnection)connection;
        command.CommandType = CommandType.Text;

        return command;
    }

    public override IDbCommand CreateStoredProcCommand(string procName, IDbConnection connection)
    {
        SqlCommand command = (SqlCommand)CreateCommand();

        command.CommandText = procName;
        command.Connection = (SqlConnection)connection;
        command.CommandType = CommandType.StoredProcedure;

        return command;
    }

    public override IDataParameter CreateParameter(string parameterName, object parameterValue)
    {
        return new SqlParameter(parameterName, parameterValue);
    }
}

这是我创建的两个类.

推荐答案

该功能已存在.

将连接字符串添加到app/webb.config:

Add a connection string to app/webb.config:

<connectionStrings>
    <add name="TheDatabase" providerName="System.Data.OleDb" connectionString="Provider=OraOLEDB.Oracle.1;Persist Security Info=False;User Id=xxx;Password=yyy;Data Source=zzzz;Extended Properties="/>
  </connectionStrings>

使用工厂建立连接:

var connectionString = ConfigurationManager.ConnectionStrings["TheDatabase"];
var providerName = connectionString.ProviderName;
var factory = DbProviderFactories.GetFactory(providerName);

获得连接:

var connection = factory.CreateConnection();

获取命令:

var command == connection.CreateCommand();

您唯一需要做的就是在app/web.config中切换驱动程序.不需要其他更改.

The only thing you need to do is to switch driver in the app/web.config. No other changes are required.

public class Database
{
    public static IDbConnection CreateOpenConnection()
    {
        var connectionString = ConfigurationManager.ConnectionStrings["TheDatabase"];
        var providerName = connectionString.ProviderName;
        var factory = DbProviderFactories.GetFactory(providerName);
        var connection = factory.CreateConnection();
        connection.Open();
        return connection;
    }
}

class FlowerManager : DataWorker
{
    public static void GetFlowers()
    {
        using (IDbConnection connection = Database.CreateOpenConnection())
        {
            using (IDbCommand command = connection.CreateCommand("SELECT * FROM FLOWERS", connection))
            {
                using (IDataReader reader = command.ExecuteReader())
                {
                    // ...
                }
            }
        }
    }
}

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