开发自己的Data Access Application Block[下篇]

上接： [原创] 我的ORM: 开发自己的Data Access Application Block - Part I 4. Database 下面来介绍重中之重：Database，绝大部分的DataAccess 操作都集中在这个Abstract Database中。这是一个相对庞大的Class，所以不得不采用Partial Class的方式来编写。

下面来介绍重中之重：Database，绝大部分的Data Access 操作都集中在这个Abstract Database中。这是一个相对庞大的Class，所以不得不采用Partial Class的方式来编写。

Part I：Field 和Property

这些Field 和Property基本上对应我们前面的Configuraiton。此为我们定义了三个Field 和Property：DbDataAdapter，Connection，_transaction。考虑到垃圾回收，使Database实现IDisposable接口。值得说明一点的是，我们通过Database的DatabaseProviderFactory创建了泛型的DbDataAdapter，DbConnection和Transaction。

• ConnectionString：string

• DatabaseProviderFactory：DbProviderFactory

• DefaultCommandType：CommandType

• UseCommandBuilder：bool

• DbParameterNameMapping：IDbParameterNameMapping

• StoredProcedureNameMapping：IStoredProcedureNameMapping

• DbDataAdapter：DbDataAdapter

• Connection: DbConnection

• Transaction: DbTransaction

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.Common;

using Artech.ApplicationBlock.DataMapping;

namespace Artech.ApplicationBlock.DataAccess
{
/**////

Database defines a series of database-based operations.

Database : IDisposable

{
private bool _isDisposed;

The five private fields possess the corressponding pubic properties, and they are only allowed to be evaluated by Database Factory.#region The five private fields possess the corressponding pubic properties, and they are only allowed to be evaluated by Database Factory.
private DbProviderFactory _dbProviderFactory;
private string _connectionString;
private CommandType _defaultCommandType;
private bool _useCommandBuilder;
private IDbParameterNameMapping _dbParameterNameMapping;
private IStoredProcedureNameMapping _storedProcedureNameMapping;

/**////

/// Database connection string which is specified by the database factory.
///
public string ConnectionString
{
get
{
return this._connectionString;
}

set
{
this._connectionString = value;
}
}

/**////

/// The concrete database specific provider factory.
///
public DbProviderFactory DatabaseProviderFactory
{
get
{
return this._dbProviderFactory;
}
set
{
this._dbProviderFactory = value;
}
}

/**////

/// The defaull command type to perform the database operations which do not specify the commanf type.
///
public CommandType DefaultCommandType
{
get
{
return this._defaultCommandType;
}
set
{
this._defaultCommandType = value;
}
}

/**////

///Determine whether to use command builder or mapped stored procedures to execute database operations.
///
public bool UseCommandBuilder
{
get
{
return this._useCommandBuilder;
}
set
{
this._useCommandBuilder = value;
}
}

/**////

/// A string which indicates the type to perform mapping between stored procedure parameter and source column.
///
public IDbParameterNameMapping DbParameterNameMapping
{
get
{
return this._dbParameterNameMapping;
}
set
{
this._dbParameterNameMapping = value;
}
}

/**////

/// A string which indicates the type to perform mapping between table name and the related stored procedure names.
///
public IStoredProcedureNameMapping StoredProcedureNameMapping
{
get
{
return this._storedProcedureNameMapping;
}
set
{
this._storedProcedureNameMapping = value;
}
}
#endregion

Connection & Database DataAdapter#region Connection & Database DataAdapter
private DbDataAdapter _dbDataAdapter;
private DbConnection _connection;

/**////

/// A generic database data adapter which is responsible for save the changed data into database.
///
private DbDataAdapter DatabaseAdapter
{
get
{
if (this._dbDataAdapter == null)
{
this._dbDataAdapter = this._dbProviderFactory.CreateDataAdapter();
this._dbDataAdapter.AcceptChangesDuringUpdate = false;
this._dbDataAdapter.MissingSchemaAction = MissingSchemaAction.Add;
}

return this._dbDataAdapter;
}
}

/**////

/// The database connection.
///
private DbConnection Connection
{
get
{
if (this._connection == null)
{
this._connection = this._dbProviderFactory.CreateConnection();
this._connection.ConnectionString = this._connectionString;
}

return this._connection;
}
}
#endregion

Constructor#region Constructor
public Database()
&