13th Chapter-DELPHI Development Database Application Overview (i) (2)

Database Characteristics of 13.2.1 Delphi

Like other applications, Delphi provides a number of parts to facilitate the creation of database applications. The data members of a database object can be set at design time or by program code at run time. Delphi's widget board provides the parts to be used in the development of two-page database applications:

A part on a data access page that accesses a database table directly in the databases.

The part on the Data control page that interacts with the user to display and modify data in the database.

The database application first uses the database components provided by Delphi to establish contact with BDE and then contact the database via BDE. The following diagram illustrates the relationship between Delphi Database Tools and Components, Delphi database application and BDE, and data sources.

The following table summarizes the database features of Delphi:

Table 13.1 Delphi Database Features

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Main uses of tools and components

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Data Access Components access to databases, database tables, storage processes, etc.

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Data Control components interacts with the user, providing an interface to display and modify the database

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Database Desktop (DBD) to establish, index, query tables of databases, and access, edit from various data

The data in

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Reportsmith Create, browse, and print data in a database table

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Borland DB Engine database application access to data in dBASE Paradox database through BDE

(BDE) and data from the local InterBase database server

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BDE Configuration establishes and manages the database that the BDE uses when establishing a connection to the database.

Utility Alias

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It is a single user, multiple-routine local SQL database server that can be

Local interbase server is used in stand-alone environments to develop or test client/server database applications

program, and then expand it into a remote database server such as

ORACLE, SyBase, Informix, etc.

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InterBase SQL Link connects the Delphi database application to a local interbase server

Driver Program

Delphi These features enable us to create database applications that are flexible enough to connect with DBASE, Paradox, local interbase database servers, and to access data easily through BDE. When we create a simple database should use the above tools and components provided by Delphi without even having to write any programs.

BDE is automatically included in Delphi, so when creating a database application, we don't have to be concerned about what BDE is about. The Delphi installer automatically installs the appropriate drivers for Paradox, dBASE, and local interbaseserver, and establishes the relevant configuration, DBE Configuration Utility can establish the connection information between the application and the database. You can also set aliases for the database.

The following table lists the features of Delphi development Client/server applications that extend Delphi's ability to access remote databases, such as SQL database servers (ORACLE, SyBase, Informix, Microsoft sql Server, InterBase).

Table 13.2 Delphi Client/server Database Features

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Main use of tools

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SQL link and reportsmith in SQL drivers are

SQL Drivers Delphi Database application provides access to remote SQL

Server drivers, such as access to Oracle, SyBase,

Microsoft SQL Server, Informix, intermix

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Visual Query Builder creates a visual way to create SQL statements against database tables and tables

To manipulate the records in

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SQL Links enables Delphi database applications to access data residing on remote servers using SQL language, including Oracle, Sybase, Microsoft SQL Server, Informix, InterBase. After the SQL link driver is installed, the SQL statement can directly manipulate the data on the server.

13.2.2 Delphi Access to data sources (DataSource)

Delphi database applications get the data they need through BDE, BDE with different types of data sources, BDE can use data sources as shown in table 13.3

Table 13.3 Delphi accessible Data source

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Data source (DataSource) attribute description file name extension

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Database tables are managed by the dBASE database management system or

The dBASE database is established in DBD, and each table is a separate file. Dbf

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Database tables are managed through the Paradox database system. Db

Paradox database or DBD established, each table is a separate file

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The ASCII file table is established through the database desktop, each. Txt

The table is a separate file

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The local interbase server database is managed through the InterBase database system. Gdb

Established, multiple tables are included in a database file

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SQL database server: The database is supplied by the corresponding database server depending on the different

Oracle,sybase,informix dedicated or general-purpose tools can also be managed through the DBD database

Microsoft SQL Server creates a database and accesses the database system via SQL link

InterBase

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ODBC data sources mainly refer to those database systems with ODBC interfaces that depend on the corresponding

Databases such as Ms Access,btrieve

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