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94-710: UDL may refer to: Universal Data Link , a file format storing information about database connections Universal Design for Learning , an educational framework University of Lleida ( Universitat de Lleida ), a university in Lleida, Spain Urban debate league , a high school debate teams group in the United States User defined literals , ways to customize literals in C++ programming language since C++11. Topics referred to by

188-489: A physical quantity . The protocol defines the rules, syntax , semantics , and synchronization of communication and possible error recovery methods . Protocols may be implemented by hardware , software , or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses predetermined for that particular situation. The specified behavior

282-402: A tunneling arrangement to accommodate the connection of dissimilar networks. For example, IP may be tunneled across an Asynchronous Transfer Mode (ATM) network. Protocol layering forms the basis of protocol design. It allows the decomposition of single, complex protocols into simpler, cooperating protocols. The protocol layers each solve a distinct class of communication problems. Together,

376-475: A .NET Managed Provider, a modified version of an OLE DB provider specifically designed for .NET. The object structure is no longer built around a Recordset object. Instead a Dataset object is used to contain data gathered from multiple sources. This is transparent to the programmer. Unlike the old ADO Recordset, the Dataset's design promotes the use of disconnected data. Conceptually, a Dataset object can be seen as

470-669: A coarse hierarchy of functional layers defined in the Internet Protocol Suite . The first two cooperating protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP) resulted from the decomposition of the original Transmission Control Program, a monolithic communication protocol, into this layered communication suite. The OSI model was developed internationally based on experience with networks that predated

564-599: A computer environment (such as ease of mechanical parsing and improved bandwidth utilization ). Network applications have various methods of encapsulating data. One method very common with Internet protocols is a text oriented representation that transmits requests and responses as lines of ASCII text, terminated by a newline character (and usually a carriage return character). Examples of protocols that use plain, human-readable text for its commands are FTP ( File Transfer Protocol ), SMTP ( Simple Mail Transfer Protocol ), early versions of HTTP ( Hypertext Transfer Protocol ), and

658-721: A conflict could arise that caused the OLE DB Session Pooling to run at 100% CPU usage. This was later fixed. Microsoft published a full list of bugs fixed in MDAC 2.5 Service Pack 2 and MDAC 2.5 Service Pack 3 . A security vulnerability also existed (later fixed) whereby an unchecked buffer was found in the SQL Server Driver. This flaw was introduced in MDAC 2.5 SP2. MDAC 2.6 was released in September 2000 and

752-400: A convenient level of indirection . Additionally, the dialog box specifies a number of alternate OLE DB data providers for a variety of target applications. Open Database Connectivity (ODBC) is a native interface that is accessed through a programming language (usually C ) that can make calls into a native library . In MDAC this interface is defined as a DLL. A separate module or driver

846-681: A coordinated, stand-alone setup program." The MDAC 1.0 stack consisted of ODBC 3.0, OLE DB 1.1, ADO 1.0, and the Advanced Data Connector (ADC) 1.0 – which according to Microsoft was the precursor to the Remote Data Service of MDAC 1.5. It also included ODBC drivers for Access/Jet, SQL Server and Oracle databases. MDAC 1.0 was released via several mechanisms: the Advanced Data Connector shipped with Internet Information Server (IIS) 3.0 and as

940-546: A downloadable cab file ; OLE DB 1.1 and ADO 1.0 shipped with the OLE DB 1.1 SDK, which came with Visual Studio 97 and was also downloadable. MDAC 1.0 came with Active Server Pages, that itself came in IIS 3.0, and also came with Visual InterDev 1.0. MDAC 1.5 was released between September 1997 and March 1998, and involved a more centralised distribution mechanism than MDAC 1.0. It was released with Microsoft Internet Explorer 4.0,

1034-501: A downloadable component and will support it on their 64-bit operating systems. Several components have been completely removed from MDAC by Microsoft and are no longer supported. They are: Microsoft has released several versions of MDAC over time. The distribution method has varied and the feature-set is different for each version. MDAC 1.0 was first released in August 1996. According to Microsoft, "MDAC 1.0 existed more as concept than

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1128-456: A machine rather than a human being. Binary protocols have the advantage of terseness, which translates into speed of transmission and interpretation. Binary have been used in the normative documents describing modern standards like EbXML , HTTP/2 , HTTP/3 and EDOC . An interface in UML may also be considered a binary protocol. Getting the data across a network is only part of the problem for

1222-457: A networking protocol, the protocol software modules are interfaced with a framework implemented on the machine's operating system. This framework implements the networking functionality of the operating system. When protocol algorithms are expressed in a portable programming language the protocol software may be made operating system independent. The best-known frameworks are the TCP/IP model and

1316-417: A packet-switched network, rather than this being a service of the network itself. His team was the first to tackle the highly complex problem of providing user applications with a reliable virtual circuit service while using a best-effort service , an early contribution to what will be the Transmission Control Protocol (TCP). Bob Metcalfe and others at Xerox PARC outlined the idea of Ethernet and

1410-554: A protocol. The data received has to be evaluated in the context of the progress of the conversation, so a protocol must include rules describing the context. These kinds of rules are said to express the syntax of the communication. Other rules determine whether the data is meaningful for the context in which the exchange takes place. These kinds of rules are said to express the semantics of the communication. Messages are sent and received on communicating systems to establish communication. Protocols should therefore specify rules governing

1504-451: A redistributable package. Throughout its history, MDAC has been the subject of several security flaws , which led to attacks such as an escalated privileges attack , although the vulnerabilities were generally fixed in later versions and fairly promptly. The current version is 2.8 service pack 1, but the product has had many different versions and many of its components have been deprecated and replaced by newer Microsoft technologies. MDAC

1598-565: A reference model for communication standards led to the OSI model , published in 1984. For a period in the late 1980s and early 1990s, engineers, organizations and nations became polarized over the issue of which standard , the OSI model or the Internet protocol suite, would result in the best and most robust computer networks. The information exchanged between devices through a network or other media

1692-474: A security vulnerability that results because one of the ODBC functions in MDAC that is used to connect to data sources contained an unchecked buffer. Another vulnerability that was fixed was one whereby an attacker could respond to an SQL Server discovery message broadcast by clients with a specially crafted packet that could cause a buffer overflow. Another flaw was found whereby code could be executed remotely when

1786-478: A set of cooperating processes that manipulate shared data to communicate with each other. This communication is governed by well-understood protocols, which can be embedded in the process code itself. In contrast, because there is no shared memory , communicating systems have to communicate with each other using a shared transmission medium . Transmission is not necessarily reliable, and individual systems may use different hardware or operating systems. To implement

1880-461: A single interface that other software could use to access Microsoft databases. Jet also provided support for security, referential integrity , transaction processing , indexing , record and page locking, and data replication. In later versions of Jet, the engine was extended to run SQL queries, store character data in Unicode format, create views , and allowed bi-directional replication with

1974-673: A single communication. A group of protocols designed to work together is known as a protocol suite; when implemented in software they are a protocol stack . Internet communication protocols are published by the Internet Engineering Task Force (IETF). The IEEE (Institute of Electrical and Electronics Engineers) handles wired and wireless networking and the International Organization for Standardization (ISO) handles other types. The ITU-T handles telecommunications protocols and formats for

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2068-532: A small in-memory relational database in its own right that allows for manipulation of data in any direction. In order to propagate changes back into the database, a DataAdapter object is used that transfers data from between the data source and the DataSet object. Cursors were also deprecated in ADO.NET, being replaced with a DataReader object, which is used to efficiently process a large list of results one record at

2162-456: A standardization process. Such protocols are referred to as de facto standards . De facto standards are common in emerging markets, niche markets, or markets that are monopolized (or oligopolized ). They can hold a market in a very negative grip, especially when used to scare away competition. From a historical perspective, standardization should be seen as a measure to counteract the ill-effects of de facto standards. Positive exceptions exist;

2256-456: A time without storing them. MDAC is a continually evolving component framework. As such, there have been several components that were previously part of it but have since been deprecated or removed entirely from the framework. Jet stands for Joint Engine Technology and was a database engine used for Microsoft Access , Microsoft Exchange Server and Visual Basic . Jet was part of a Relational Database Management System (RDBMS) and offered

2350-430: A transfer mechanism of a protocol is comparable to a central processing unit (CPU). The framework introduces rules that allow the programmer to design cooperating protocols independently of one another. In modern protocol design, protocols are layered to form a protocol stack. Layering is a design principle that divides the protocol design task into smaller steps, each of which accomplishes a specific part, interacting with

2444-434: Is a high-level programming interface to OLE DB. It uses a hierarchical object model to allow applications to programmatically create, retrieve, update and delete data from sources supported by OLE DB. ADO consists of a series of hierarchical COM-based objects and collections, an object that acts as a container of many other objects. A programmer can directly access ADO objects to manipulate data, or can send an SQL query to

2538-447: Is almost entirely functionally equivalent to MDAC 2.8." There are two ways of checking the version of MDAC that is installed on a computer. For Windows 2000, Windows XP and Windows Server 2003, one way to check is via Microsoft's Component Checker program, which compares the value of each installed MDAC DLL to the MDAC file manifest. The second way is to check the key HKEY_LOCAL_MACHINE\Software\Microsoft\DataAccess\FullInstallVer in

2632-773: Is conceptually divided into consumers and providers . The consumers are the applications that need access to the data, and the provider is the software component that exposes an OLE DB interface through the use of the Component Object Model (or COM). OLE DB is the database access interface technology used by MDAC. OLE DB providers can be created to access such simple data stores as a text file or spreadsheet , through to such complex databases as Oracle and SQL Server . However, because different data store technology can have different capabilities, OLE DB providers may not implement every possible interface available. The capabilities that are available are implemented through

2726-532: Is different from Wikidata All article disambiguation pages All disambiguation pages Universal Data Link The first version of MDAC was released in August 1996. At that time Microsoft stated MDAC was more a concept than a stand-alone program and had no widespread distribution method. Later Microsoft released upgrades to MDAC as web-based redistributable packages. Eventually, later versions were integrated with Microsoft Windows and Internet Explorer , and in MDAC 2.8 SP1 they ceased offering MDAC as

2820-453: Is governed by rules and conventions that can be set out in communication protocol specifications. The nature of communication, the actual data exchanged and any state -dependent behaviors, is defined by these specifications. In digital computing systems, the rules can be expressed by algorithms and data structures . Protocols are to communication what algorithms or programming languages are to computations. Operating systems usually contain

2914-551: Is needed for each database that must be accessed. The functions in the ODBC API are implemented by these DBMS-specific drivers. The driver that Microsoft provides in MDAC is called the SQL Server ODBC Driver (SQLODBC), and (as the name implies) is designed for Microsoft's SQL Server. It supports SQL Server v6.5 and upwards. ODBC allows programs to use SQL requests that will access databases without having to know

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3008-511: Is not supported on Windows 98 or Windows Me. OLE DB (also called OLEDB or OLE-DB) allows MDAC applications access to different types of data stores in a uniform manner. Microsoft has used this technology to separate the application from data can store in the website the data store that it needs to access. This was done because different applications need access to different types and sources of data, and do not necessarily need to know how to access technology-specific functionality. The technology

3102-555: Is now an official component of the Microsoft's operating system, though they will be providing ongoing bug and security fixes to previously released versions of the web-distributable version. However, Microsoft have created a new component called the SQL Native Client (SQLNCLI), which is a stand-alone data access API that has combined the OLE DB and ODBC libraries into one DLL. It was formed to be independent of MDAC, which

3196-542: Is now known as Windows DAC in Windows Vista . The latest version of MDAC (2.8) consists of several interacting components, all of which are Windows specific except for ODBC (which is available on several platforms). MDAC architecture may be viewed as three layers: a programming interface layer, consisting of ADO and ADO.NET , a database access layer developed by database vendors such as Oracle and Microsoft ( OLE DB , .NET managed providers and ODBC drivers), and

3290-931: Is now reliant on the state the operating system is in – a developer now links to this library and avoids situations where an update of the operating system which updates MDAC breaks applications built to a different version of MDAC. Windows 7 SP1 has broken forward compatibility of MDAC 2.8. Software compiled on Windows 7 SP1 that relies on MDAC ADO will not work on Windows versions prior to Windows 7 SP1 (including Windows 7 RTM, Vista, XP). Microsoft has provided solutions to work around this issue for some applications but VBA applications remain affected. The fix for this issue has been release in February 2012. Windows Vista will no longer use MDAC, but instead use Windows DAC, which consists of updated versions of ADO, OLE DB, and ODBC components. According to Microsoft, "Windows DAC includes some changes to work with Windows Vista, but

3384-513: Is of course impossible because you would then have a negative context switch rate - the drop is either 33% or 60% depending on which planet the author was on at the time of writing) for a 10-user workload. They were unimpressed that a fundamental functional change to the default behaviour of Net-Lib occurred without more than a passing mention in an unrelated document. Windows XP users also sometimes experienced problems connecting to SQL Server because SQL Server attempts to use certificates it finds on

3478-449: Is referred to as communicating sequential processes (CSP). Concurrency can also be modeled using finite state machines , such as Mealy and Moore machines . Mealy and Moore machines are in use as design tools in digital electronics systems encountered in the form of hardware used in telecommunication or electronic devices in general. The literature presents numerous analogies between computer communication and programming. In analogy,

3572-499: Is the OLE DB provider that Microsoft provides for the Microsoft SQL Server from version 6.5 upwards. Universal data link files (or '.udl files') provide a common user interface for specifying connection attributes. A user can use a Data Link Properties dialog box to save connection information in a .udl file as an alternative to directly specifying them by hand in a connection string. Consequently, these files provide

3666-408: Is the synchronization of software for receiving and transmitting messages of communication in proper sequencing. Concurrent programming has traditionally been a topic in operating systems theory texts. Formal verification seems indispensable because concurrent programs are notorious for the hidden and sophisticated bugs they contain. A mathematical approach to the study of concurrency and communication

3760-594: Is typically independent of how it is to be implemented . Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard . A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: protocols are to communication what programming languages are to computations . An alternate formulation states that protocols are to communication what algorithms are to computation . Multiple protocols often describe different aspects of

3854-776: The National Physical Laboratory in the United Kingdom, it was written by Roger Scantlebury and Keith Bartlett for the NPL network . On the ARPANET , the starting point for host-to-host communication in 1969 was the 1822 protocol , written by Bob Kahn , which defined the transmission of messages to an IMP. The Network Control Program (NCP) for the ARPANET, developed by Steve Crocker and other graduate students including Jon Postel and Vint Cerf ,

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3948-423: The OSI model . At the time the Internet was developed, abstraction layering had proven to be a successful design approach for both compiler and operating system design and, given the similarities between programming languages and communication protocols, the originally monolithic networking programs were decomposed into cooperating protocols. This gave rise to the concept of layered protocols which nowadays forms

4042-638: The PARC Universal Packet (PUP) for internetworking. Research in the early 1970s by Bob Kahn and Vint Cerf led to the formulation of the Transmission Control Program (TCP). Its RFC   675 specification was written by Cerf with Yogen Dalal and Carl Sunshine in December 1974, still a monolithic design at this time. The International Network Working Group agreed on a connectionless datagram standard which

4136-516: The Windows NT operating system line's Win32 subsystem . The SQL Server Network Library is controlled through the use of a Client Network Utility, which is bundled with the SQL Server. Each Net-Lib supported network protocol has a separate driver (not to be confused with a device driver ), and has support for a session layer in its protocol stack. There are two general types of Net-Lib:

4230-459: The Windows registry . Microsoft notes that this information may be incorrect for versions of MDAC prior to 2.1 when compared with the versions of the MDAC files installed to the system No bulletins released 1.5 Network protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any variation of

4324-547: The finger protocol . Text-based protocols are typically optimized for human parsing and interpretation and are therefore suitable whenever human inspection of protocol contents is required, such as during debugging and during early protocol development design phases. A binary protocol utilizes all values of a byte , as opposed to a text-based protocol which only uses values corresponding to human-readable characters in ASCII encoding. Binary protocols are intended to be read by

4418-590: The public switched telephone network (PSTN). As the PSTN and Internet converge , the standards are also being driven towards convergence. The first use of the term protocol in a modern data-commutation context occurs in April 1967 in a memorandum entitled A Protocol for Use in the NPL Data Communications Network. Under the direction of Donald Davies , who pioneered packet switching at

4512-481: The Internet Client SDK 4.0 and through a CD-ROM given out at the 1997 Professional Developers Conference (PDC). There were five versions of MDAC 1.5: The different versions of MDAC 1.5 consisted of: This version of MDAC had a security flaw that made it vulnerable to an escalated privileges attack . The vulnerability caused systems that had both IIS and MDAC installed to give an unauthorized web user

4606-551: The MSDASQL component for their 64-bit operating systems and the Microsoft Oracle ODBC driver was later superseded by a .NET Managed Oracle Provider, which supported Oracle 9i. However, Windows Server 2008 and Windows Vista SP1 ship with a 64-bit version of MSDASQL. Remote Data Services (RDS) allowed the retrieval of a set of data from the server, which the client then altered in some way and then sent back to

4700-744: The Microsoft SQL Server. It was superseded by MSDE which was superseded SQL Server Express . There were three modules to Jet. One was the Native Jet ISAM Driver , a Jet dynamic link library (DLL) that could directly manipulate Microsoft Access database files (MDB), which was a modified form of an Indexed Sequential Access Method (ISAM) database. Another one of the modules were the ISAM Drivers , DLLs that allowed access to ISAM databases, among them being Xbase , Paradox , Btrieve and FoxPro files. The final module

4794-479: The ability to execute shell commands on the IIS system as a privileged user. This allowed the attacker to use MDAC to tunnel SQL and other ODBC data requests through the public connection to a private back-end network when on a multi-homed Internet-connected IIS system. It also allowed the user to gain unauthorized access to secured, non-published files on the IIS system MDAC 1.5 was the last data access component release supported under Windows NT 3.51 SP5. MDAC 2.0

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4888-456: The approval or support of a standards organization , which initiates the standardization process. The members of the standards organization agree to adhere to the work result on a voluntary basis. Often the members are in control of large market shares relevant to the protocol and in many cases, standards are enforced by law or the government because they are thought to serve an important public interest, so getting approval can be very important for

4982-411: The attacker responded to the broadcast with another specially crafted packet. MDAC 2.8 was released in August 2003 and distributed with Microsoft Windows Server 2003 , as well as on Microsoft's Data Access Technologies website. It did not introduce any new features to the product but fixed a number of bugs and security issues – a reg file (automates changes to the registry) was removed that made

5076-448: The basis of protocol design. Systems typically do not use a single protocol to handle a transmission. Instead they use a set of cooperating protocols, sometimes called a protocol suite . Some of the best-known protocol suites are TCP/IP , IPX/SPX , X.25 , AX.25 and AppleTalk . The protocols can be arranged based on functionality in groups, for instance, there is a group of transport protocols . The functionalities are mapped onto

5170-506: The choice of writing applications which directly access OLE DB and ODBC. The Microsoft SQL Server Network Library (also known as Net-Lib) is used by the Microsoft SQL Server to read and write data using many different network protocols . Though Net-Lib is specific to the SQL Server, Microsoft includes it with MDAC. The SQL Server uses the Open Data Services (ODS) library to communicate with Net-Lib, which interfaces directly with

5264-512: The cluster, directly or through the installation of another program, it may cause a catastrophic failure of the SQL Server Agent or other SQL Server services." This issue affected Veritas Software 's Backup Exec 9.0 for Windows Servers, because it installs Microsoft SQL Server 2000 Desktop Engine (MSDE 2000) as its database. Revision 4367 installed MDAC version 2.6 SP2 while revision 4454 installed MDAC version 2.7 SP1, which did not have

5358-442: The content being carried: text-based and binary. A text-based protocol or plain text protocol represents its content in human-readable format , often in plain text encoded in a machine-readable encoding such as ASCII or UTF-8 , or in structured text-based formats such as Intel hex format , XML or JSON . The immediate human readability stands in contrast to native binary protocols which have inherent benefits for use in

5452-581: The database itself. These component layers are all made available to applications through the MDAC API . The Microsoft SQL Server Network Library, a proprietary access method specific to Microsoft SQL Server, is also included in the MDAC. Developers of Windows applications are encouraged to use ADO or ADO.NET for data access, the benefit being that users of the application program are not constrained in their choice of database architecture except that it should be supported by MDAC. Naturally, developers still have

5546-466: The database via several ADO mechanisms. ADO is made up of nine objects and four collections . The collections are: The objects are: ADO.NET is the latest version of ADO (after ADO 2.8, now often referred to as ADO Classic) and is part of the MDAC 2.8 stack alongside classic ADO. It is built around Microsoft .NET . Though sometimes seen as an evolutionary step up from ADO, some fundamental structural changes were made by Microsoft. ADO.NET runs through

5640-673: The field of computer networking, it has been historically criticized by many researchers as abstracting the protocol stack in this way may cause a higher layer to duplicate the functionality of a lower layer, a prime example being error recovery on both a per-link basis and an end-to-end basis. Commonly recurring problems in the design and implementation of communication protocols can be addressed by software design patterns . Popular formal methods of describing communication syntax are Abstract Syntax Notation One (an ISO standard) and augmented Backus–Naur form (an IETF standard). Finite-state machine models are used to formally describe

5734-654: The full Data Access SDK. MDAC 2.1 was distributed with SQL Server 7.0 and SQL Server 6.5 SP5. MDAC 2.1 SP1 was distributed with Internet Explorer 5 and MDAC 2.1 SP1a (GA) was distributed with Microsoft Office 2000, BackOffice 4.5 and Visual Studio 98 SP3. However, none of these versions of MDAC were released to the general public via the World Wide Web . MDAC 2.1 SP2 was distributed from Microsoft's website. The components that were included with 2.1 were: This version had security vulnerabilities whereby an unchecked buffer could allow an elevated privileges attack. This

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5828-426: The horizontal message flows (and protocols) are between systems. The message flows are governed by rules, and data formats specified by protocols. The blue lines mark the boundaries of the (horizontal) protocol layers. The software supporting protocols has a layered organization and its relationship with protocol layering is shown in figure 5. To send a message on system A, the top-layer software module interacts with

5922-643: The internet as a reference model for general communication with much stricter rules of protocol interaction and rigorous layering. Typically, application software is built upon a robust data transport layer. Underlying this transport layer is a datagram delivery and routing mechanism that is typically connectionless in the Internet. Packet relaying across networks happens over another layer that involves only network link technologies, which are often specific to certain physical layer technologies, such as Ethernet . Layering provides opportunities to exchange technologies when needed, for example, protocols are often stacked in

6016-476: The layers make up a layering scheme or model. Computations deal with algorithms and data; Communication involves protocols and messages; So the analog of a data flow diagram is some kind of message flow diagram. To visualize protocol layering and protocol suites, a diagram of the message flows in and between two systems, A and B, is shown in figure 3. The systems, A and B, both make use of the same protocol suite. The vertical flows (and protocols) are in-system and

6110-427: The layers, each layer solving a distinct class of problems relating to, for instance: application-, transport-, internet- and network interface-functions. To transmit a message, a protocol has to be selected from each layer. The selection of the next protocol is accomplished by extending the message with a protocol selector for each layer. There are two types of communication protocols, based on their representation of

6204-581: The local computer, however if there is more than one certificate available it did not know which one to use. When attempting to use Microsoft Analysis Services 2000 RTM, an error would sometimes appear when trying to browse cubes. Microsoft also discovered a problem in Windows 95 , Windows 98 , and Windows Me 's setup program which prevented the MDAC installation program from rolling back when it encountered an installation error. Several security issues were resolved by Microsoft for MDAC 2.7. David Litchfield of Next Generation Security Software Ltd reported

6298-402: The module directly below it and hands over the message to be encapsulated. The lower module fills in the header data in accordance with the protocol it implements and interacts with the bottom module which sends the message over the communications channel to the bottom module of system B. On the receiving system B the reverse happens, so ultimately the message gets delivered in its original form to

6392-587: The network library protocol might unexpectedly switch to TCP/IP , even if the DSN was configured to use named pipes . This issue was found by InfoWorld reporter Randall C. Kennedy , who identified that the change was actually made in MDAC 2.6 but was never documented. It was discovered when testing client/server database workloads on a Windows XP computer; InfoWorld claims that although overall server CPU utilization rose by only 8 percent using TCP/IP, context switches per second dropped by more than 150 percent (which

6486-417: The operating system does not allow any other process access to the instances' area of shared memory. Net-Lib is also able to support the impersonation of a logged in user's security context for protocols that support authenticated connections (called trusted connections ). This allows Net-Lib to provide an integrated logon authentication mechanism via the use of Windows Authentication . Windows Authentication

6580-470: The other parts of the protocol only in a small number of well-defined ways. Layering allows the parts of a protocol to be designed and tested without a combinatorial explosion of cases, keeping each design relatively simple. The communication protocols in use on the Internet are designed to function in diverse and complex settings. Internet protocols are designed for simplicity and modularity and fit into

6674-457: The possible interactions of the protocol. and communicating finite-state machines For communication to occur, protocols have to be selected. The rules can be expressed by algorithms and data structures. Hardware and operating system independence is enhanced by expressing the algorithms in a portable programming language. Source independence of the specification provides wider interoperability. Protocol standards are commonly created by obtaining

6768-594: The primary and the secondary. The primary Net-Lib consists of a Super Socket Net-Lib and the Shared Memory Net-Lib, while there are numerous secondary Net-Libs, including TCP/IP and named pipes network libraries (named pipes are a method of communicating with other processes via a system-persistent pipeline that is given an identity). The Microsoft OLE DB Provider for SQL Server (SQLOLEDB) communicates via primary Net-Libs. The Super Socket Net-Lib deals with inter-computer communications and coordinates

6862-633: The problem MDAC 2.7 was released in October 2001 through Microsoft's website. A refresh release was issued in April 2002 through the release of Windows XP and through Microsoft's website. Version 2.7 was available in U.S. English , Chinese (Traditional and Simplified), German, Japanese, Korean, Brazilian Portuguese , Czech , Danish, Greek, Slovak , Slovenian , Spanish, Finnish, French, Hungarian, Italian, Dutch , Norwegian, Polish, Portuguese, Russian, Swedish, and Turkish . Hebrew and Arabic were only available through Windows XP. The main feature change

6956-531: The proprietary interfaces to the databases. It handles the SQL request and converts it into a request that the individual database system understands. According to Microsoft, "After SQL Server 2012, the ODBC driver will be updated for the most recent server features, including Microsoft Windows Azure SQL Database, and released as the Microsoft ODBC Driver for SQL Server." ActiveX Data Objects ( ADO )

7050-401: The protocol, creating incompatible versions on their networks. In some cases, this was deliberately done to discourage users from using equipment from other manufacturers. There are more than 50 variants of the original bi-sync protocol. One can assume, that a standard would have prevented at least some of this from happening. In some cases, protocols gain market dominance without going through

7144-539: The protocol. The need for protocol standards can be shown by looking at what happened to the Binary Synchronous Communications (BSC) protocol invented by IBM . BSC is an early link-level protocol used to connect two separate nodes. It was originally not intended to be used in a multinode network, but doing so revealed several deficiencies of the protocol. In the absence of standardization, manufacturers and organizations felt free to enhance

7238-502: The router. The Super Socket Net-Lib also handles data encryption via the use of the Windows SSL API. The Shared Memory Net-Lib, on the other hand, manages connections between multiple instances of SQL Server that exist on one computer. It uses a shared memory area to communicate between the processes. This is inherently secure; there is no need for data encryption between instances of SQL Server that exist on one computer as

7332-403: The same term [REDACTED] This disambiguation page lists articles associated with the title UDL . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=UDL&oldid=1047270817 " Category : Disambiguation pages Hidden categories: Short description

7426-517: The secondary Net-Libs – though the TCP/IP secondary Net-Lib is an exception in that it calls on the Windows Sockets 2 API directly. The Banyan VINES , AppleTalk , ServerNet , IPX/SPX , Giganet , and RPC Net-Libs were dropped from MDAC 2.5 onwards. The Network Library router had the job of managing all these protocols, however now only the named pipes secondary Net-Lib is managed by

7520-660: The server for further processing. With the popular adoption of Transact-SQL , which extends SQL with such programming constructs as loops and conditional statements, this became less necessary and it was eventually deprecated in MDAC 2.7. Microsoft produced SOAP Toolkit 2.0, which allows clients to do this via an open XML -based standard. SQLXML was designed for SQL Server 2000, but was deprecated with MDAC 2.6. It allowed Microsoft's relational database to be viewed by XPath and allowed data to viewable as an XML file. It has not actually been deprecated but has been removed from later versions of MDAC, though Microsoft does provide it as

7614-542: The server run in an "unsafe" mode whereby the RDS could be exploited to gain unauthorized access to the system and a new restriction was imposed on the length of the Shape query string. There were also several ODBC Administrator changes. On May 23, 2005, Brad Rhodes (Lead Program Manager of Microsoft Data Access Technologies) announced that MDAC 2.8 SP1 was the last stand-alone redistributable of MDAC that Microsoft will ship. MDAC

7708-461: The top module of system B. Program translation is divided into subproblems. As a result, the translation software is layered as well, allowing the software layers to be designed independently. The same approach can be seen in the TCP/IP layering. The modules below the application layer are generally considered part of the operating system. Passing data between these modules is much less expensive than passing data between an application program and

7802-506: The transmission. In general, much of the following should be addressed: Systems engineering principles have been applied to create a set of common network protocol design principles. The design of complex protocols often involves decomposition into simpler, cooperating protocols. Such a set of cooperating protocols is sometimes called a protocol family or a protocol suite, within a conceptual framework. Communicating systems operate concurrently. An important aspect of concurrent programming

7896-406: The transport layer. The boundary between the application layer and the transport layer is called the operating system boundary. Strictly adhering to a layered model, a practice known as strict layering, is not always the best approach to networking. Strict layering can have a negative impact on the performance of an implementation. Although the use of protocol layering is today ubiquitous across

7990-501: The use of COM objects – an OLE DB provider will map the data store technology's functionality to a particular COM interface. Microsoft calls the availability of an interface to be "provider-specific" as it may not be applicable depending on the database technology involved. Additionally, however, providers may also augment the capabilities of a data store; these capabilities are known as services in Microsoft parlance. The Microsoft OLE DB Provider for SQL Server (SQLOLEDB)

8084-654: Was an OLE DB provider for allowing ActiveX Data Objects access to databases via any ODBC driver. Microsoft supplied several OLE-DB providers (for the Indexing Service, Active Directory , Jet, SQL Server, Oracle ( MSDAORA ) and Internet Publishing), however unless otherwise directed, ADO defaulted to using MSDASQL as the default provider. After MDAC 2.5 both the Oracle ODBC driver and MSDASQL supported Oracle 7 and partially supported Oracle 8i. Features that were not supported were: Microsoft initially deprecated

8178-717: Was distributed through the web and with Microsoft SQL Server 2000 MDAC 2.6 RTM, SP1 (released June 20, 2001), and SP2 (released June 11, 2002) were distributed in parallel with the Microsoft SQL Server 2000 service packs, and could also be downloaded from the Microsoft website. Beginning with this version of MDAC, Microsoft Jet, Microsoft Jet OLE DB Provider, and the ODBC Desktop Database Drivers were not included. Instead, these could be installed manually. Microsoft also released an alert warning that MDAC 2.6 should not be installed on an SQL Server 7.0 Cluster, because "if you install MDAC 2.6 or later on any node in

8272-549: Was distributed with the Data Access 2.0 SDK and included the contents of MDAC 1.5, the ODBC 3.5 SDK and the OLE DB 1.5 SDK, and the OLE DB for OLAP Specification. It also had included many updates to the core product, including a security feature added to the RDS which prevented it from being used maliciously an IIS server. This version came included in Windows NT 4.0 SP4, and also with Visual Studio 6.0, which came with

8366-415: Was first implemented in 1970. The NCP interface allowed application software to connect across the ARPANET by implementing higher-level communication protocols, an early example of the protocol layering concept. The CYCLADES network, designed by Louis Pouzin in the early 1970s was the first to implement the end-to-end principle , and make the hosts responsible for the reliable delivery of data on

8460-616: Was found some time later and it affected MDAC 2.1, 2.5 and 2.6 and was addressed in a later patch MDAC 2.5 was released on February 17, 2000, and distributed with Windows 2000 , and the MDAC service packs were released in parallel with the Windows 2000 service packs. They were also distributed through Microsoft's website. Three service packs were released. The components included with 2.5 were: Several issues were found in this version of MDAC. When using OLE DB Session Pooling, Microsoft COM+ would try to continuously load and unload OLE DB, and

8554-588: Was presented to the CCITT in 1975 but was not adopted by the CCITT nor by the ARPANET. Separate international research, particularly the work of Rémi Després , contributed to the development of the X.25 standard, based on virtual circuits , which was adopted by the CCITT in 1976. Computer manufacturers developed proprietary protocols such as IBM's Systems Network Architecture (SNA), Digital Equipment Corporation's DECnet and Xerox Network Systems . TCP software

8648-524: Was redesigned as a modular protocol stack, referred to as TCP/IP. This was installed on SATNET in 1982 and on the ARPANET in January 1983. The development of a complete Internet protocol suite by 1989, as outlined in RFC   1122 and RFC   1123 , laid the foundation for the growth of TCP/IP as a comprehensive protocol suite as the core component of the emerging Internet . International work on

8742-514: Was support for Microsoft's 64-bit operating system, however support for Banyan VINES was also dropped from this version of MDAC. There were several known issues: MDAC 2.7 continued causing connectivity problems on clustered servers running Microsoft SQL Server 6.5 or SQL Server 7.0, with no workaround provided by Microsoft. When creating or configuring ODBC data source names (DSNs) using the Microsoft SQL Server ODBC driver

8836-639: Was the Data Access Objects (DAO) DLL , DAO allowed programmers access to the Jet engine. It was basically an object-oriented data language used by Access Basic and Visual Basic application developers to access Jet. Similarly, the Microsoft Jet OLE DB Provider and Replication Objects (JRO) which allowed replication between Jet data sources was removed from MDAC 2.6 The Microsoft OLE DB Provider for ODBC, or MSDASQL ,

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