LOBS, BLOBS, CLOBS: Dealing with Attachments in APEX

@sthilaire wphilltech.com

LOBS, BLOBS, CLOBS

Dealing with Attachments in APEX

Tim St. Hilaire

Feb 2014

http://www.enkitec.com/apex/f?p=16000:1:1334296126571201



The Plan

• Intro

• The Goal

• APEX BLOB Wizard

• Making It Your Own

• Base Technology

• Advanced Database Concepts

• Questions



Introduction

Tim St. Hilaire

• System Integrator

• Problems Solver

• Pragmatist

• Technology Enthusiast

• APEX Fan

• Enkitec Product Developer



The Goal

• Ability to accept file attachment input from users in an application

• Use the content in applications either as text, images, or downloadable to users

• Understand how the data is stored, retrieved, and managed inside the database



Demonstration – The Goal



The Academics



The Academics

• LOB – Large Objects – broken down into datatypes – BLOB - Stores unstructured binary data in the

database as a bit stream

– CLOB – Stores large amounts of text such as XML in the database character set

– NCLOB – National Character Set LOB – stores Unicode data

– BFILE – external LOB

– Secure File LOB – file data enabling advanced features such as compression and encryption



BLOB vs. CLOB

• BLOB – Stream of data intended to be binary

– Chunks are returned in RAW format (substr)

• CLOB – Will translate between character sets

– Chunks are returned in VARCHAR2 format (substr)

SELECT * FROM

NLS_DATABASE_PARAMETERS WHERE

PARAMETER = 'NLS_CHARACTERSET';



There are 10 types of people in the world…

Those that understand binary, and those that don’t.

-- The Internet



APEX



Demonstration - APEX Submit Button



Where did the file go?

WWV_FLOW_FILES

APEX_APPLICATION_FILES



Table Context Sensitivity

• APEX_APPLICATION_FILES – limits to files available in the workspace.

• Includes files that were uploaded by all applications in a workspace

• Includes files that have been uploaded via the builder

• Includes Static Shared Component Files for the Application and the Workspace



Evaluate WWV_FLOW_FILES

Pros

• No Table Creations Required

• Consistent Implementation

• Storage in a known location

Cons

• Need Remote Key Storage

• Application Files combined

• Storage for all Workspaces is shared

• Some Files are publicly available



Custom Table



My Table

• To configure your own table

• Minimum Requirements

• Adjust to Features and Business Requirements

ID NUMBER (your choice)

ACTUAL_FILE BLOB

MIME_TYPE VARCHAR2

FILE_NAME VARCHAR2



Custom Table CREATE TABLE MY_APEX_FILES(

BLOB_ID NUMBER NOT NULL,

NAME VARCHAR2(100 BYTE),

DESCRIPTION VARCHAR2(2000 BYTE),

CATEGORY VARCHAR2(200 BYTE),

PUBLIC_FLAG VARCHAR2(1 BYTE),

BLOB_CONTENT BLOB,

BLOB_SIZE NUMBER,

MIME_TYPE VARCHAR2(255 BYTE),

FILE_NAME VARCHAR2(255 BYTE),

CREATED_BY VARCHAR2(50 BYTE),

CREATED_ON DATE,

UPDATED_BY VARCHAR2(50 BYTE),

UPDATED_ON DATE);



Referencing



Form - File Browse Settings



Form - Display Images















Form - Difference

<img id="P210_IMAGE" src="apex_util.get_blob_file?a=500&s=970034890998301&p=210&d=27553826455759041&i=27566106354076381&p_pk1=321230641481386783828770868593367722825&p_pk2=&p_ck=D164075B30411E1CF29B6B9ED9A57684" alt="Hunger" title="Hunger">

<img id="P210_IMAGE_SELECT" src="wwv_flow.show?p_request=NATIVE%3DC825C6CF697537EC53FBD9065B8B0827585481276038A327CEF5A150CAC67389&p_instance=970034890998301&p_flow_id=500&p_flow_step_id=210">



Report - Showing Contents



Report – BLOB Field

• When writing SQL, the report column is NOT the BLOB content Field – as much as a reference to the content



Report – Numbers Required

• The Report column is calculated as SIZE

• Using the APEX format mask / generator, it must be a number.



Report Content = SIZE

• Note – You can store the size when the row is written for easy syntax



Notes From the Field

• The Mime Type and File Name is important for usability




• The report column containing the primary key must be named the same as the primary key field in the BLOB table – even if the BLOB table is not in the report

• Fields are ignored based on format selections (inline vs. download)



Report - Include Download



Link Creation Result

<a href="apex_util.get_blob?s=8634949024800&a=500&c=3473415610798872&p=200&k1=3418001856547833&k2=&ck=BD47E34C8E5A3058299ECD457A4574B4&rt=IR" alt="Download"

title="Download 58KB">Download</a>




• Case Sensitive Names

“Apex_application_files”

!=

APEX_APPLICATION_FILES



Report - Include Image



Report - Include Image

As a Column in a Select Statement: CASE

WHEN MIME_TYPE LIKE 'image%' THEN '<img src="'||apex_util.get_blob_file_src(

'P210_BLOB_CONTENT',ID)||

'" height="75" width="75" />'

ELSE NULL

END as shrunk



Text



Quiz

What is the size limit of a VARCHAR2?

(A) 255

(B) 2000

(C) 4000

(D) 32767

(E) 8 Terabytes

(F) Whatever it is defined as….



Maximum Width



Rich Text Editor

Character Limit!

Or

The most descriptive error messages ever…



Demonstration – Text Region Error



Plugin – Rich Text



The Next Level of Complexity



Once Upon a Time….

@apexins.sql

Tablespace_apex

tablespace_files

tablespace_temp

images

@apexins.sql

SYSAUX

SYSAUX

TEMP

/i/



Specify LOB Storage Location

CREATE TABLE ContainsLOB_tab (

n NUMBER,

c CLOB)

lob (c) STORE AS BASICFILE segname

(TABLESPACE lobtbs1

CHUNK 4096

PCTVERSION 5

NOCACHE LOGGING

STORAGE (MAXEXTENTS 5)

);



Demonstration – Text Region Plugin



Size of Tables

SELECT

l.table_name||'-lob',

s.bytes

FROM user_lobs l,

user_segments s

WHERE

s.segment_name = l.segment_name

AND

s.segment_type = 'LOBSEGMENT'



Size Matters

ALTER TABLE MY_TABLE DEALLOCATE UNUSED;

ALTER TABLE MY_TABLE enable ROW MOVEMENT;

ALTER TABLE MY_TABLE SHRINK SPACE cascade;

ALTER TABLE MY_TABLE disable ROW MOVEMENT;

Find a DBA to Partner With





Questions and Comments




References Many thanks to all those that have come before me, and for those that take the time to help others grow and improve their skills by sharing their time an knowledge.

• Enkitec Plugin – http://www.enkitec.com/products/plugins

• Demonstration Application – http://wphilltech.com

• APEX Docs – BLOB in APEX 17.10 http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35125/advnc_blob.htm#HTMDB25906 – GET_BLOB_FILE_SRC http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35127/apex_util.htm#AEAPI129

• DBMS_LOB – http://docs.oracle.com/cd/E11882_01/appdev.112/e25788/d_lob.htm

• Oracle SecureFiles and Large Objects – http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_tables.htm – http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_lob_ops.htm

• APEX Builder - BLOB Support in Forms and Reports – http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35125/advnc_blob.htm

• Icons – http://www.stdicon.com/


http://www.enkitec.com/products/plugins

http://www.enkitec.com/products/plugins

http://wphilltech.com/

http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35125/advnc_blob.htm#HTMDB25906




http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35127/apex_util.htm#AEAPI129



http://docs.oracle.com/cd/E11882_01/appdev.112/e25788/d_lob.htm



http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_tables.htm

http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_tables.htm

http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_lob_ops.htm

http://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_lob_ops.htm

http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35125/advnc_blob.htm

http://docs.oracle.com/cd/E37097_01/doc/doc.42/e35125/advnc_blob.htm

http://www.stdicon.com/

http://www.stdicon.com/


Disclaimer

• Marks, images, brands and referenced content are the property of their respective owners. Usage is for discussion purposes only. No ownership assumed or implied.

• The comments and opinions expressed here are sole responsibility of the author and not of his employer or any other party.

• No trees were harmed during the creation of this presentation. However, a great number of electrons were terribly inconvenienced.
