(eBook) - Borland Delphi SQL User Guide.PDF - Delphi - stan-lej

SQL Links for Windows

Delphi for Windows

Introduction

Agreement

Borland SQL Links for Windows enables users to access and manipulate SQL data using

features in Borland applications.

Supported Borland applications

Any Borland application that supports the Borland Database Engine (BDE) can use

Borland SQL Links. The cornerstone of all Borland Windows-based database products,

the BDE (also known as IDAPI, the Integrated Database Application Programming

Interface) supports Paradox for Windows, dBASE for Windows, Delphi 95, and custom

applications built using the BDE API.

For the purpose of this manual, we refer to all supported Borland database products and

custom applications as BDE applications.

Supported databases

Drivers in the SQL Links product package support InterBase, Informix, ORACLE, and

SYBASE and Microsoft SQL Server databases.

Where to find information

This book describes how Borland SQL Links for Windows works, how to install one or

more SQL Link drivers, and how to set up your supported Borland application to access

SQL data. It includes appendices which provides driver-specific information on

required workstation software, configuration parameters, troubleshooting, and data

translation.

It is meant to be used with:

• your BDE application user documentation, which describes how to use your product

to access both local (workstation-based) and SQL server data

• your BDE application programming documentation, which describes how to write

custom applications to use with both local and SQL server data

Introduction 1

User’s Guide

• your SQL server documentation

Depending on how you plan to work with SQL data, you may not need to read through

all of the above books. The following table shows what kind of information each type of

SQL Links user needs, and where to find it in SQL Links and related documentation.

Table Intro.1 Where to find information on SQL Links and related topics

Who you are

What you do

Information you need

Where to find it

BDE application end-user

(no knowledge of SQL)

Use Borland desktop or

custom applications to

work with both local and

SQL data (graphical user

interface only)

How to install SQL Links

Borland SQL Links for

Windows User’s Guide

Borland SQL Links for

Windows User’s Guide

BDE application user

documentation

How to create one or more

aliases to the SQL database

How to connect to the SQL

database through your

BDE application

How to work with local and

SQL data through your

Borland desktop graphical

user interface (GUI)

BDE application user

documentation

BDE application end-user

(knows SQL)

Use supported application

to pass SQL statements to

local and/or SQL data

How to install SQL Links

Borland SQL Links for

Windows User’s Guide

Borland SQL Links for

Windows User’s Guide

BDE application user

documentation

How to create one or more

aliases to the SQL database

How to connect to the SQL

database through your

BDE application

How to frame SQL

statements the server can

accept and work with

How to pass SQL

statements from your BDE

application directly to the

SQL server

SQL server documentation

BDE application user

documentation and/or

online Help

BDE application

developer

Adapt existing applications

(or write new ones) for use

in a mixed workstation/

SQL environment

How to install SQL Links

Borland SQL Links for

Windows User’s Guide

How to create one or more

aliases to the SQL database

Borland SQL Links for

Windows User’s Guide

Differences between

workstation databases and

SQL databases

Product-specific online

Help for SQL and upsizing

issues

Programming tools

available to create

applications that will work

in a mixed workstation/

SQL environment

Product-specific online

Help for SQL and upsizing

issues, BDE application

programmer’s reference

Summary information on

data type translation,

language driver usage, and

other general factors that

influence the interaction

between the Borland

application and the server

Driver-specific appendix in

the Borland SQL Links

User’s Guide

How to frame SQL

statements the server can

accept and work with

SQL server documentation

2 SQL Links User’s Guide

Other important sources of information include the Borland SQL Links README file

(READLINK.TXT)and the IDAPI Configuration Utility online Help.

Terms and conventions

The Borland SQL Links manuals use special typefaces to help you distinguish between

keys to press, names of objects, menu commands, and text to be entered. The following

table lists these conventions:

Table Intro.2 SQL Link documentation conventions

Convention

Applies to

Examples

Bold type

Method names, error and information

messages, and text the user types in

insertRecord

Paradox displays the message Index

error on key field

Enter a:\install

Italic type

Glossary terms, variables, emphasized

words

Answer table, searchButton, searchVal

ALL CAPS

DOS files and directories, reserved

words, operators, types of SQL queries

CONNECT.EXE, C:\WINDOWS,

CREATE

Initial Caps

Applications, fields, menu commands,

data types

Sample application, Price field,

Form | View Data command,

Interval data type

Keycap Font

Keys on the computer keyboard

F1, Enter

Monospaced font

Code examples

myTable.open(“sites.db”)

Introduction 3

4 SQL Links User’s Guide

Chapter 1

How Borland SQL Links work

This chapter provides a general overview of the Borland SQL Links and how they work

with a Borland Database Engine (BDE) application.

Introduction

If you work in a setting where you need to share access to files or printers, you are

probably familiar with the idea of a local area network , or LAN. A LAN enables

workstation users to share files, software, and printer resources stored on dedicated

machines called servers . Workstations connect to network servers through a system of

cabling, communications hardware, and software. In large user populations, two or

more LANs can connect through gateways to form wide area networks , or WANs.

In a network environment, your workstation uses the network server in much the same

way as it uses its own hard disk. If your workstation needs access to data stored on the

server’s hard disk it requests that data from the server. The server sends the requested

data over the network and back to your workstation where it is processed locally.

However, the network server differs from the workstation in that server data can be

accessed by more than one user at the same time.

The database server

A database server is a computer that processes high-level database requests. Although

other types of network servers let most processing occur on the user’s workstation,

database servers are active, with most processing occurring on the database server itself.

If your workstation needs access to data stored in a database server, you query the server

directly. The database server processes the query itself and sends only the answer over

the network and back to your workstation.

Since the processing is performed at the server and not at the workstation that

originated the request, the workstation becomes a client of the database server. In a

client/server system , multiple clients (users) request the services of the database server

Chapter 1, How Borland SQL Links work 5

Chapter

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