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ODBC Driver Guide

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Introduction

This chapter introduces ODBC, the c-treeACE SQL ODBC driver, and how they work together to provide access from a wealth of desktop tools to c-treeACE SQL environments:

  • A c-treeACE SQL environment is an SQL interface over c-tree.
  • ODBC: Microsoft’s Open Data Base Connectivity has become a widely accepted database access standard on the desktop.
  • Desktop tools and applications that support ODBC can access any data source supported by an ODBC driver. These tools include client/server development, query, and personal productivity tools.

In V11 and later, c-treeACE SQL ODBC drivers for Unix are available on AIX and Solaris (Sparc) platforms.

Overview of ODBC

The Open Database Connectivity (ODBC) interface from Microsoft has emerged as the standard mechanism for client applications to access data from a variety of different sources through a single interface. Users of applications supporting ODBC merely select a new database from a point-and-click menu to connect transparently to that data source.

To become accessible from ODBC client applications, database environments must provide software, called a driver, on the client system where the application resides. The driver translates the standard ODBC function calls into calls the data source can process, and returns data to the application. Each data source provides a driver on the client system for applications to use to access data from that source.

The c-treeACE SQL ODBC Driver extends this plug-and-play interoperability to c-treeACE SQL. It allows any Microsoft Windows tool or application that supports the ODBC call library to easily use c-treeACE SQL as a data source. With it, applications based on tools such as and Visual Basic can include c-treeACE SQL as a data source.

The ODBC interface specifies two major components:

  • A library of function calls that allow applications to connect with a database system and issue statements through an application programming interface (API)
  • Syntax for Structured Query Language (SQL) statements, based on existing standards

ODBC drivers fit in as a layer of “middleware” in the ODBC architecture. The ODBC architecture includes the following layers:

Application

An ODBC application is any program that calls ODBC functions and uses them to issue SQL statements. For example, many vendors have added ODBC support to their existing Windows-based tools, such as PowerBuilder™ and Impromptu®, so those tools can use ODBC for data access.

ODBC Driver Manager

A Microsoft-supplied dynamic-link library (DLL) that routes calls from an application to the appropriate ODBC driver for a data source. An application sees the ODBC driver manager and a driver as a single entity that processes requests to a particular data source. The ODBC driver manager loads the requested driver in response to an application’s call to the ODBC SQLConnect() or SQLDriverConnect() functions.

ODBC Driver

A dynamic link library (DLL) that processes ODBC function calls for a specific data source. The driver connects to the data source and translates the standard SQL statements into syntax the data source can process. It also returns any requested data to the application. There are ODBC drivers for every major database system.

Data Source

The combination of a database system, the operating system it uses, and any network software required to access it. (ODBC defines a database system (DBMS) as any vendor’s implementation of a data access system that provides an SQL interface.)

The following figure shows the components involved in a typical ODBC environment.

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