Tuesday, 15 November 2016

Client Communication with Teradata

Client applications can connect to Teradata Database using one of the following methods:
Network-attached through a Local Area Network (LAN)- Workstation Attachment Methods
Channel-attached through an IBM mainframe- Mainframe Attachment Method

Workstation Attachment Methods
Workstation-attached methods include:
.NET Data Provider for Teradata
Java Database Connectivity (JDBC)
OLE DB Provider for Teradata
Open Database Connectivity (ODBC)
Teradata CLIv2 for workstation-attached systems
The following figure illustrates the transparent connection between client applications and Teradata Database.


.NET Data Provider for Teradata
The .NET Data Provider for Teradata conforms to the ADO.NET specifications. ADO.NET provides a rich set of data access services to .NET Framework applications. The Data Provider allows .NET applications to access Teradata Database from all .NET Framework languages including C#, VB, F# and PowerShell.

Java Database Connectivity
JDBC is a specification for an API. The API allows platform-independent Java applications to access Teradata Database using SQL and external stored procedures.
The JDBC API provides a standard set of interfaces for:
Opening connections to databases
Executing SQL statements
Processing results
Teradata JDBC Driver provides access to Teradata Database using the Java language. Teradata JDBC Driver is a type 4 (pure Java) JDBC Driver. It is a set of Java classes that use TCP/IP to communicate directly with Teradata Database.

OLE DB Provider for Teradata
OLE DB Provider for Teradata allows programmers to design application programs that allow access between Teradata Database and data stores that do no use SQL. The application program (the consumer) requests database information from an intermediate program (the provider), which accesses Teradata Database. The intermediate program receives the response from Teradata Database and returns a copy of the desired data to the application program.
OLE DB Provider for Teradata also uses service providers. A service provider enhances the functionality of a provider; for example, the Microsoft Cursor Service for OLE DB adds client‑side cursor support to any provider.

Open Database Connectivity
ODBC Driver for Teradata provides an interface to Teradata Databases using the industry standard ODBC API. ODBC Driver for Teradata provides Core‑level SQL and Extension‑level 1 (with some Extension‑level 2) function call capability using the Windows Sockets (WinSock) Transmission Control Protocol/Internet Protocol (TCP/IP) communications software interface. ODBC operates independently of CLI.
Teradata CLIv2 for Workstation-Attached Systems
Teradata CLIv2 for workstation-attached systems is a Teradata proprietary API and library providing an interface between applications on a TCP/IP-connected client and Teradata Database server.
Teradata CLIv2 for workstation-attached systems can:
Build parcels which are packaged by Micro Teradata Director Program (MTDP) and sent to Teradata Database using the Micro Operating System Interface (MOSI).
Manage all interactions between the application and Teradata Database.
Provide an application with a pointer to data rows returned from Teradata Database.

MTDP
MTDP is the interface between Teradata CLIv2 for workstation-attached systems and MOSI.
 Functions of MTDP include:
Session initiation and termination
Logging, verification, recovery, and restart
Physical input to and output from the server
Note: MTDP does not control session balancing; session balancing on workstation‑attached systems is controlled by Teradata Database Gateway on the server.

MOSI
MOSI is the interface between MTDP and Teradata Database. MOSI is a library of service routines providing operating system independence among clients that access Teradata Database. With MOSI, only one version of MTDP is required to run on all workstation‑attached platforms.
Mainframe Attachment Method
Mainframe attachment uses Teradata CLIv2 for mainframe-attached systems.

Teradata CLIv2 for Mainframe-Attached Systems
Teradata CLIv2 for mainframe-attached systems is a collection of callable service routines providing the interface between applications and the Teradata Director Program (TDP) on an IBM mainframe client. Teradata CLIv2 for mainframe-attached systems can operate with all versions of IBM operating systems, including Customer Information Control System (CICS), Information Management System (IMS), and IBM System z Operating System.
By way of TDP, Teradata CLIv2 for mainframe-attached systems sends requests to the server and provides client applications with responses from the server.
Teradata CLIv2 for mainframe-attached systems provides support for:
Managing multiple serially executed requests in a session
Managing multiple simultaneous sessions to the same or different servers
Using cooperative processing so an application can perform operations on the client and the server at the same time
Generally insulating the application from the details of communicating with a server

Teradata Director Program
TDP manages communications between Teradata CLIv2 for mainframe-attached systems and the Teradata Database server. TDP executes on the same mainframe as Teradata CLIv2 for mainframe-attached systems, but runs as a different job or virtual machine. Although an individual TDP is associated with one logical server, any number of TDPs may operate and be simultaneously accessed by Teradata CLIv2 for mainframe-attached systems on the same mainframe. Each TDP is referred to by an application using an identifier called the TDPid that is unique in a mainframe; for example, TDP2.
Functions of TDP include:
Session initiation and termination
Logging, verification, recovery, and restart
Physical input to and output from the server, including session balancing and queue maintenance
Security

Teradata Database Server
A server implements the actual relational database that processes requests received from Teradata CLIv2 for mainframe-attached systems by way of TDP. The following figure illustrates the logical structure of the client-server interface on mainframe‑attached systems.




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