Delphi database architecture. A Delphi database application is built using Delphi database development tools, Delphi data-access components

A Delphi database application is built using Delphi database development tools, Delphi data-access components, and data-aware GUI components. A database application uses Delphi components to communicate with the Borland Database Engine (BDE), which in turn communicates with databases. The following figure illustrates the relationship of Delphi tools and Delphi database applications to the BDE and data sources:

Figure 1.1. Delphi database architecture

The following table summarizes Delphi’s database features.

Table 1.1 Database features summary

Tool	Purpose
Data Access components	Access databases, tables, stored procedures, and custom component editors.
Data Control components	Provide user interface to database tables.
Database Desktop (DBD)	Create, index, and query Paradox and dBASE tables, and SQL databases. Access and edit data from all sources.
ReportSmith	Create, view, and print reports.
Borland Database Engine (BDE)	Access data from file-based Paradox and dBASE tables, and from local InterBase server databases.
BDE Configuration Utility	Create and manage database connection Aliases used by the BDE.
Local InterBase Server	Provides a single-user, multi-instance desktop SQL server for building and testing Delphi applications, before scaling them up to a production database, such as Oracle, Sybase, Informix, or InterBase on a remote server.
InterBase SQL Link	Native driver that connect Delphi applications to the Local InterBase Server.

These features enable you to build database applications with live connections to Paradox and dBASE tables, and the Local InterBase Server through the BDE. In many cases, you can create simple data access applications with these components and their properties without writing a line of code.

The BDE is built into Delphi components so you can create database applications without needing to know anything about the BDE. The Delphi installation program installs drivers and sets up configuration for Paradox, dBASE, and the Local InterBase Server, so you can begin working with tables native to these systems immediately. The BDE Configuration Utility enables you to tailor database connections and manage database aliases.

Advanced BDE features are available to programmers who need more functionality. These features include local SQL, which is a subset of the industry-standard SQL that enables you to issue SQL statements against Paradox and dBASE tables; low-level API function calls for direct engine access; and ODBC support for communication with other ODBC-compliant databases, such as Access and Btrieve.

Delphi includes Borland ReportSmith, so you can embed database report creation, viewing, and printing capabilities in Delphi database applications. Delphi also includes the Database Desktop (DBD), a tool that enables you to create, index, and query desktop and SQL databases, and to copy data from one source to another.

The following table lists the additional database features available in the Client/server edition of Delphi. These features extend Delphi’s database capabilities to access remote SQL database servers such as Sybase, Microsoft SQL Server, Oracle, Informix, and InterBase.

Table 1.2 Additional Delphi Client/Server database features

Tool	Purpose
SQL Drivers	Both SQL Links and ReportSmith provide native drivers that connect Delphi database applications to remote SQL database servers, such as Oracle, Sybase, Microsoft SQL Server, Informix, and InterBase.
Visual Query Builder	Creates SQL statements by visually manipulating tables and columns.

SQL Links provide Delphi applications with SQL access to data residing on remote servers, including Sybase, Microsoft SQL Server, Oracle, and Informix. When an SQL Link driver is installed, SQL statements are passed directly to the server for parsing and execution.

Дата добавления: 2015-10-26