HOST Built-in Command in Oracle Forms

Description

• Executes an indicated operating system command.

Syntax

PROCEDURE HOST

(system_command_string VARCHAR2);

PROCEDURE HOST

(system_command_string VARCHAR2,

screen_action NUMBER);

Built-in Type unrestricted procedure

Enter Query Mode yes

Parameters

system_command_string  

       Specifies the system command you want to pass to your particular operating system.  

screen_action  

       Specifies one of the following constants:

No parameter

• Specifies that Oracle Forms will: clear the screen prompt the operator to return from the command

NO_PROMPT

• Specifies that Oracle Forms will:
• Clear the screen (does not prompt the operator to return from the command)

NO_SCREEN

Specifies that Oracle Forms will:

• Not clear the screen
• Not prompt the operator to return from the system command

(The HOST command should not send output to the screen when using the NO_SCREEN parameter.)

Usage notes

• Note that the command interpreter for Microsoft Windows 2000 and XP is cmd. Before using the HOST Built-in to run an external command, be sure to check for the operating system and pass the appropriate command string.

• The host command operates on the application server machine. Any screen output that it performs is not visible to the user of the application.

HOST Examples

/*** built-in: HOST**

Example: Execute an operating system command in a ** subprocess or subshell.

Uses the ** 'Get_Connect_Info' procedure from the **

GET_APPLICATION_PROPERTY example. */

PROCEDURE Mail_Warning( send_to VARCHAR2) IS

the_username VARCHAR2(40);

the_password VARCHAR2(40);

the_connect VARCHAR2(40);

the_command VARCHAR2(2000);

BEGIN

      /* ** Get Username, Password, Connect information */

      Get_Connect_Info(the_username,the_password,the_connect);

      /* ** Concatenate together the static text and values of **

      local variables to prepare the operating system command ** string. */

      the_command := 'orasend '|| ' to='||send_to|| ' std_warn.txt '|| ' subject="## LATE PAYMENT ##"'||

       ' user='||the_username|| ' password='||the_password|| ' connect='||the_connect; Message('Sending Message...', NO_ACKNOWLEDGE);

       Synchronize;

       /* ** Execute the command string as an O/S command The ** NO_SCREEN option tells forms not to clear the screen *

       * while we do our work at the O/S level "silently". */

       Host( the_command, NO_SCREEN );

       /* ** Check whether the command succeeded or not */

       IF NOT Form_Success THEN

            Message('Error -- Message not sent.');

       ELSE Message('Message Sent.');

       END IF;

END;