Data Access Technologies Road Map

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Data Access Technologies Road Map

Prash Shirolkar, Author
Alyssa Henry, Contributor
Stephen Pepitone, Contributor
Acey J. Bunch, Contributor
Microsoft Corporation

Created: January 2002
Revised: December 2004

Summary: Learn about the past, present, and future of the Microsoft data access technologies. (8 printed pages)

Contents

Introduction
Microsoft Data Access Components (MDAC)
Current MDAC Architecture
Current MDAC Components
Deprecated MDAC Components
MDAC ReleasesSQL Native Client
ADO.NET
Obsolete Data Access Technologies
For More Information

 

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Introduction

This article describes the past, present, and future of Microsoft data access technologies, including DB-Library, ESQL, DAO, Microsoft® Data Access Components (MDAC) (including ODBC, ADO, and OLE DB), ADO.NET, and SQL Native Client. This article identifies which technologies are being enhanced, and which technologies and components are being deprecated or excluded from future releases.

Microsoft Data Access Components (MDAC)

With Microsoft Data Access Components (MDAC), developers can connect to and use data from a wide variety of relational and non-relational data sources. You can connect to many different data sources using ActiveX® Data Objects (ADO), Open Database Connectivity (ODBC), or OLE DB. You can do this through providers and drivers that are either built and shipped by Microsoft, or that are developed by various third parties.

Current MDAC Architecture

With the current MDAC architecture, client-server, n-tier, or Web browser applications can access SQL, Semi-Structured, and Legacy Data stores. Additionally, with MDAC (depending on requirements), these applications have the flexibility to access the data using ADO, OLE DB, or ODBC.

Figure 1. Current MDAC architecture

For the purposes of this document, you can divide the MDAC stack into the following components, based on technology and products:

• ADO (Including ADOMD and ADOX)
• OLE DB (including SQL Server OLE DB Provider, Oracle OLE DB Provider, OLE DB Provider for ODBC Drivers, Data Shape Provider, and Remote Data Provider)
• ODBC (including SQL ODBC Driver and Oracle ODBC Driver)

Current MDAC Components

These components are supported in the current release. Use these components when you develop new applications or upgrade existing applications.

• ADO: ActiveX Data Objects (ADO) provides a high-level programming model that will continue to be enhanced. Although a little less performant than coding to OLE DB or ODBC directly, ADO is straightforward to learn and use, and can be used from script languages such as Microsoft Visual Basic® Scripting Edition (VBScript) or Microsoft JScript®.
• ADOMD: ADO Multi-Dimensional (ADOMD) is to be used with multi-dimensional data providers such as Microsoft OLAP Provider, also known as Microsoft Analysis Services Provider. No major feature enhancements have been made to it since MDAC 2.0; however, it will be available on the 64-bit Microsoft Windows® operating system.
• ADOX: ADO Extensions for DDL and Security (ADOX) enables the creation and modification of definitions of a database, a table, an index, or a stored procedure. You can use ADOX with any provider. The Microsoft Jet OLE DB Provider provides full support for ADOX, while the Microsoft SQL OLE DB Provider provides limited support. No major enhancements are planned for ADOX in future MDAC releases; however, it will be available on the 64-bit Windows operating system.
• OLE DB: OLE DB is a comprehensive set of COM interfaces for accessing a diverse range of data in a variety of data stores. OLE DB providers exist for accessing data in databases, file systems, message stores, directory services, workflow, and document stores. OLE DB core services (though not every OLE DB provider) will be available on the 64-bit Windows operating system.
• SQLOLEDB: Microsoft OLE DB Provider for SQL Server (SQLOLEDB) supports access to Microsoft SQL Server 6.5 and later. This OLE DB Provider will be the primary focus of future MDAC feature enhancements. It will be available on the 64-bit Windows operating system.
• Microsoft SQL Server Network Libraries: The SQL Server Network Libraries allow SQLOLEDB and SQLODBC to communicate with the SQL Server database. The following SQL Server Network Libraries are currently deprecated in MDAC releases: Banyan Vines, AppleTalk, Servernet, IPX/SPX, Giganet, and RPC. TCP/IP, Named Pipes, and Shared Memory SQL Server Network Libraries will continue to be enhanced and will be available on the 64-bit Windows operating system.
• ODBC: The Microsoft Open Database Connectivity (ODBC) interface is a C programming language interface that allows applications to access data from a variety of Database Management Systems (DBMS). Applications using this API are limited to accessing relational data sources only. ODBC will be available on the 64-bit Windows operating system.
• SQLODBC: Microsoft SQL Server ODBC Driver (SQLODBC) enables access to Microsoft SQL Server 6.5 and later. SQLODBC will be available on the 64-bit Windows operating system.

Deprecated MDAC Components

These components are still supported in the current release of MDAC, but might be removed in future releases. Microsoft recommends that when you develop new applications, you avoid using these components. Additionally, when you upgrade or modify existing applications, remove any dependency on these components.

• Jet: Starting with version 2.6, MDAC no longer contains Jet components. In other words, MDAC 2.6, 2.7, 2.8, and all future MDAC releases do not contain Microsoft Jet, Microsoft Jet OLE DB Provider, or the ODBC Desktop Database Drivers.
• MSDASQL: The Microsoft OLE DB Provider for ODBC (MSDASQL) provides ADO clients access to databases through ODBC Drivers. This has been the default provider for ADO; however, for future releases of MDAC and the 64-bit Windows operating system, MSDASQL has been deprecated. Therefore, to access the database from ADO, clients must use appropriate Native OLE DB Providers, such as SQLOLEDB, to access Microsoft SQL Server. MSDASQL will be not available on the 64-bit Windows operating system; however, it will still be possible to use on the 64-bit Windows operating system through the 32-bit Windows subsystem.
• MSDADS: With the Microsoft OLE DB Provider for Data Shaping (MSDADS), you can create hierarchical relationships between keys, fields, or rowsets in an application. No major feature enhancements have been made since MDAC 2.1. This Provider has been deprecated in future MDAC releases. Microsoft recommends that you use XML instead of MSDADS.
• Oracle ODBC: The Microsoft Oracle ODBC Driver (Oracle ODBC) provides access to Oracle database servers. It provides full support for Oracle 7. It also uses Oracle 7 emulation to provide limited support for Oracle 8 databases. The Oracle ODBC Driver has not yet been tested with Oracle 9 databases.
• RDS: Remote Data Services (RDS) is a proprietary Microsoft mechanism to access remote ADO Recordset objects across the Internet or an intranet. No major feature enhancements have been made to RDS since MDAC 2.1. This component is being deprecated. Microsoft now ships the Microsoft SOAP Toolkit 2.0, in which applications can access remote data by using an open, XML-based standard. Applications that use RDS should migrate to SOAP.
• JRO: The Microsoft Jet OLE DB Provider and other related components have been removed from the MDAC stack since MDAC 2.6. Jet Replication Objects (JRO) is used only with Jet (Access) databases, basically to create or compact the Jet Database and Jet Replication Management. JRO has been deprecated and MDAC 2.7 will be its last release. It will not be available on the 64-bit Windows operating system.
• SQL XML: SQL XML provides extensions to Microsoft OLE DB Provider for SQL Server (SQLOLEDB) to allow clients to request Microsoft SQL Server 2000 data through XML, and to retrieve XML streams. It was first released with MDAC 2.6. With SQL XML Web Release 1, clients can insert, update, and delete data in SQL Server 2000 using Updategrams and Bulk Load. This component is not being deprecated, but it is being removed from future MDAC releases. Current and later versions of this product are available as Web downloads. SQL XML will be available on the 64-bit Windows operating system.

MDAC Releases

Here is a list of the supportability scenarios of past, present, and future MDAC releases, starting with the earliest.

• MDAC 1.5, MDAC 2.0, and MDAC 2.1: These versions of MDAC were independent releases that were released through the Microsoft Windows NT® Option Pack, the Microsoft Windows Platform SDK, or the MDAC Web site. These versions of MDAC are no longer supported.
• MDAC 2.5: This version of MDAC was included with the Windows 2000 operating system. Future services packs of MDAC 2.5 will be included with corresponding Windows 2000 service packs. Additionally, these MDAC services packs will be released to the MDAC Web site in accordance with the Windows 2000 service pack release schedule. You can only install this version of MDAC on Windows NT, Windows 95, and Windows 98 platforms. You can only install this version on Windows 2000 and Windows Millennium Edition platforms through the operating systems or their services packs. This version is currently supported.
• MDAC 2.6: MDAC 2.6 RTM, SP1, and SP2 were included with Microsoft SQL Server 2000 RTM, SP1, and SP2, respectively. Additionally, these MDAC service packs were released to the MDAC Web site in accordance with the Microsoft SQL Server 2000 service pack release schedule. You can install this version of MDAC and its service packs on Windows 2000, Windows Millennium Edition, Windows NT, Windows 95, and Windows 98 platforms. This version is no longer supported.
• MDAC 2.7: This version of MDAC is included with the Microsoft Windows XP RTM and SP1 operating systems. You can install this version of MDAC and its service packs on Windows 2000, Windows Millennium, Windows NT, and Windows 98 platforms. You can only install this version on the Windows XP platform through the operating system or its services packs.
  • The 32-bit version of MDAC 2.7 has been released to the MDAC Web site.
  • The 64-bit version of MDAC 2.7 will release with the 64-bit version of Windows XP only.
• MDAC 2.8: This version of MDAC is included with Windows Server 2003 and Windows XP SP2 and later.
  • The 32-bit version of MDAC 2.8 will also be released to the MDAC Web site at the same time Windows Server 2003 is released to the customer.
  • The 64-bit version of MDAC 2.8 will release with the 64-bit version of Windows Server 2003 only.

SQL Native Client (SQLNCLI)

SQL Native Client (SQLNCLI) is a data access technology that is new to Microsoft SQL Server 2005, and it is a stand alone data access Application Programming Interface (API) that is used for both OLE DB and ODBC. It combines the SQL OLE DB Provider and the SQL ODBC Driver into one native dynamic link library (DLL) while also providing new functionality that is separate and distinct from the Microsoft Data Access Components (MDAC). SQL Native Client can be used to create new applications or enhance existing applications that need to take advantage of new SQL Server 2005 features such as Multiple Active Result Sets (MARS), User-Defined Types (UDT), and XML data type support.

ADO.NET

ADO.NET is an evolutionary improvement over traditional ADO for creating distributed, data sharing applications. It is a high-level application programming interface that is targeted at loosely coupled, n-tier, Internet-based applications that support disconnected access to data. It is a core component of the Microsoft .NET Framework.

Figure 2. ADO.NET architecture

ADO.NET provides .NET-managed providers for connected access, and DataSets that read and write in XML for disconnected management of retrieved data and user interaction. The following data providers are available for ADO.NET:

• Microsoft SQL .NET Data Provider: This provider allows .NET applications to directly access a Microsoft SQL Server database.
• Microsoft OLE DB .NET Data Provider: This provider allows .NET applications to access databases using their native OLE DB Providers.
• Microsoft ODBC .NET Data Provider: This provider allows .NET applications to access databases by using their ODBC drivers.
• Microsoft Oracle .NET Data Provider: This provider allows .NET applications to access an Oracle database.

The DataSet reads and writes XML and the XMLDataDocument integrates relational and XML views.

Obsolete Data Access Technologies

Obsolete technologies are technologies that have not been enhanced or updated in several product releases and that will be excluded from future product releases. Do not use these technologies when you write new applications. When you modify existing applications that are written using these technologies, consider migrating those applications to ADO.NET.

The following components are considered obsolete:

• DB-Library: This is a SQL Server-specific programming model that includes C APIs. There have been no feature enhancements to the DB-Library since SQL Server 6.5. Its final release was with SQL Server 2000 and it will not be ported to the 64-bit Windows operating system.
• Embedded SQL (E-SQL): This is a SQL Server-specific programming model that enables Transact-SQL statements to be embedded in Visual C code. No feature enhancements have been made to the E-SQL since SQL Server 6.5. Its final release was with SQL Server 2000 and it will not be ported to the 64-bit Windows operating system.
• Data Access Objects (DAO): DAO provides access to JET (Access) databases. This API can be used from Microsoft Visual Basic®, Microsoft Visual C++®, and scripting languages. It was included with Microsoft Office 2000 and Office XP. DAO 3.6 is the final version of this technology. It will not be available on the 64-bit Windows operating system.
• Remote Data Objects (RDO): RDO was specifically designed to access remote ODBC relational data sources, and made it easier to use ODBC without complex application code. It was included with Microsoft Visual Basic versions 4, 5, and 6. RDO version 2.0 was the final version of this technology.

For More Information

For more information, visit the following Microsoft Web site:

• The Data Access and Storage Developer Center Web site

출처 : http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmdac/html/data_mdacroadmap.asp