Dr. Dobb's Journal - February 2009 - (Page 30)

d02will_p1db 12/12/08 10:31 AM Page 30 State of the Art VIDEOS AND ORACLE FORMS 10G Listing One CREATE TABLE MULTIMEDIA ( ID INTEGER, THEBLOB BLOB, FILE_NAME VARCHAR2(50 BYTE) NOT NULL, MIME_TYPE VARCHAR2(20 BYTE) NOT NULL ) TABLESPACE table_DATA1 LOGGING NOCOMPRESS LOB (THEBLOB) STORE AS ( TABLESPACE table_DATA2 ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE INDEX ( TABLESPACE table_index1 ) ) NOCACHE NOPARALLEL NOMONITORING; To store videos, you need a datatype that can hold the video Listing Two DROP DIRECTORY DOCHOME; CREATE OR REPLACE DIRECTORY DOCHOME AS '/u03/docHome'; Listing Three CREATE OR REPLACE PROCEDURE load_multimedia as l_blob blob; l_bfile bfile; begin insert into multimedia values ( 1, empty_blob(),'Gulfport.wmv' ,'video/x-ms-wmv' ) returning theblob into l_blob; l_bfile := bfilename('DOCHOME','Gulfport.wmv'); dbms_lob.fileopen(l_bfile); dbms_lob.loadfromfile( l_blob, l_bfile, dbms_lob.getlength( l_bfile) ); dbms_lob.fileclose(l_bfile); end; / continued from page 28 Creating a Stored Procedure The show_video() procedure displays videos. This procedure must be called from the web browser using a Database Access Descriptor (DAD) from your HTTP Server. I ran across this procedure (created by Brian Hill) in the OTN Reports Forum. However, I customized it for my needs; see Listing Four. In this procedure, the select statement selects the filename, mime type, and video (Blob), while the table ID equals the parameter passed in with the procedure. I use the HTP package to display a header on the web page. The HTP package consists of a set of procedures and functions to embed HTML inside PL/SQL code. The package WPG_Docload.Download_File() downloads a Blob datatype into a browser; in this case, display the video on the web page. Listing Four CREATE OR REPLACE PROCEDURE show_video (p_file_number IN NUMBER) AS l_file_name multimedia.file_name%TYPE; l_mime_type multimedia.mime_type%TYPE; l_blob_handle BLOB; BEGIN SELECT file_name, mime_type, theblob INTO l_file_name, l_mime_type, l_blob_handle FROM multimedia WHERE ID = p_file_number; -- build an http header that includes mime type and length OWA_UTIL.mime_header (NVL (l_mime_type, 'application/octet'), FALSE); HTP.p ('Content-length: ' DBMS_LOB.getlength (l_blob_handle)); HTP.p ('Content-Disposition: file_name="' l_file_name '"'); OWA_UTIL.http_header_close; -- download the file WPG_Docload.Download_File (l_blob_handle); EXCEPTION WHEN OTHERS THEN HTP.p (SQLCODE SQLERRM); END show_video; / Creating a Database Access Descriptor (DAD) According to MetaGlossary.com a database access descriptor (DAD) “is a set of values that specify how an application connects to 30 Dr. Dobb’s Journal l www.ddj.com l February 2009 http://www.MetaGlossary.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - February 2009

Dr. Dobb's Journal - February 2009 Contents Friday Night Fish Fry Alia Vox Developer Diaries Conversations Computing in the Clouds Software Development in the Cloud Videos and Oracle Forms 10g Parallel LINQ Decoupling C Header Files Effective Concurrency Disciplined Agility Swaine’s Flames

Dr. Dobb's Journal - February 2009

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