Lecture 3 multimedia databases

Multimedia Databases

Possible solutions to the R limitations

Topics Covered
 Why multimedia is a problem for databases
 Support for searching
 Types of Databases
 Relational Databases and Multimedia
– Example - Access
 Object Relational Databases and Multimedia
– Example - Oracle
 Object Oriented Databases and Multimedia
– Example - Jasmine

The problem - recap
 Data increasingly means not just numbers and small strings
but multimedia data as well – structured (text, images, video,
audio, VR, etc.)
 Databases promise:
– well structured data organisation
– efficient storage of large amounts of data
– querying
– transactional support for concurrent users
 If you include multimedia data
– multimedia is large and may swamp other data
– multimedia data structures are completely different from standard
database structures
– multimedia data structures do not easily lend themselves to content-
based searching

Data integration
 Databases already integrate various kinds of
data, numbers, dates, small text strings.
 They do this by the use of domains
– i.e. each atomic value in the database belongs to
one of a small number of types
 each type has two aspects:
– a range of values which are acceptable
– some operations which are available

Cont ….
 the schema indicates a domain for each part
of the database and the DBMS enforces the
domain constraint
– e.g. in a Relational Database, each column is
assigned a domain
 Therefore a DBMS must provide domain
types for any kind of data that they wish to
house and theoverall structure will deal with
the integration

Domain types of MM data
 DBMS typically provide three different kinds of
domain for multimedia data:
1. large object domains, sequences of data often of
two kinds
 Binary Large Objects – BLOBs – which are an unstructured
sequence of bytes
 Character Large Objects – CLOBs – which are an
unstructured sequence of characters
1. file references – instead of holding the data, a
file reference contains a link to the data (OLE in
Access)
2. genuine multimedia data types – (Oracle and
Jasmine)

Cont …
 There is an important difference between
the last of these and the first two:
– multimedia data types present the possibility of
exploiting the structure of the data for querying
and manipulation
– large objects at best allow you to extract
sections or to concatenate them
– file references mean that the DBMS has no
access the data at all

Querying MM data
A DBMS permits a user to search the database by
content e.g. give the name of the student with
matriculation number 0123456 We would like to
do the same with multimedia data e.g. give the
pictures painted by Picasso or sound files with
female singer hitting top C
 With standard data this is easy – numeric and
string operators are well understood With
multimedia data this is more difficult and requires
some method of identifying contents of which
there are two kinds:

Cont …
 automatic identification
– an algorithm takes the data and returns a
measure which can be compared – e.g. of
blackness
 manual identification
– a person examines the data and catalogues it –
e.g. in a table of pictures, there is a column for
the picture and another for the painter

Types of Database
 There are three kinds of DBMS that might be used
for housing multimedia data.
 Relational DBMS store everything as First
Normal Form tables
– all data items are atomic and are held in rectangular
tables
– data can only be related if they are in one or in two
records connected by a common value (foreign key)
– records are identified only by content
– it is difficult (if not impossible) to extend the set of
domains

Cont …
 Object-oriented DBMS store everything as
classes of objects
– all data is held as components of objects (like Java
variables)
– data is related by object reference (i.e. one class
variable has a type which is another class and the
values of that variable are instances of that class)
– the set of classes is extensible and so you can freely
create domains

Cont …
 Object-relationalDBMS are
fundamentally relations but are not First
Normal Form
– the values in cells can be object references as
well as atomic values
– new types can be defined

How can we use these
different types?
 In a relational database, you can have:
– domain types for large objects
– using a string type for file names
– extra file types as in OLE in Access
 In an object-oriented database, you can have:
– specially designed classes for multimedia
 In an object-relational database, you can have:
– specially designed types for multimedia

R type database e.g. Access and
OLE
 Object Linking and Embedding was Microsoft’s first
architecture for integrating files of different types:
 Each file type in Windows is associated with an
application It is possible to place a file of one type inside
another:
– either by wholly embedding the data in which case it is rendered
by a plug-in associated with the program
– or by placing a link to the data in which case it is rendered by
calling the original program
 Access works with this system by providing a domain type
for OLE
 • There’s not much you can do with OLE fields since the
data is in a format that Access does not understand
 • You can plug the foreign data into a report or a form and
little else

R databases e.g. BFILEs in
Oracle

 The BFILE datatype provides access to
BLOB files of up to 4 gigabytes that are
stored in file systems outside an Oracle
database.
– The BFILE datatype allows read-only support
of large binary files; you cannot modify a file
through Oracle. Oracle provides APIs to access
file data.

Large Object Types in Oracle
and SQL3
 Oracle and SQL3 support three large object types:
– BLOB - The BLOB domain type stores unstructured
binary data in the database. BLOBs can store up to four
gigabytes of binary data.
– CLOB – The CLOB domain type stores up to four
gigabytes of single-byte character set data
– NCLOB - The NCLOB domain type stores up to four
gigabytes of fixed-width and varying width multi-byte
national character set data
* SQL3 is a significant extension to standard SQL which turns into a full object-based
language

Cont …
 These types support
– Concatenation – making up one LOB by putting two
of them together
– Substring – extract a section of a LOB
– Overlay – replace a substring of one LOB with another
– Trim – removing particular characters (e.g.
whitespace) from the beginning or end
– Length – returns the length of the LOB
– Position – returns the position of a substring in a LOB
– Upper and Lower – turns a CLOB or NCLOB into
upper or lower case
– LOBs can only appear in a where clause using “=”,
“<>” or “like” and not in group by or order by at all

Large Object Types in
MySQL
MySQL has four BLOB and four CLOB (called
TEXT in MySQL) domain types:
 TINYBLOB and TINYTEXT – store up to 256
bytes
 BLOB and TEXT – store up to 64K bytes
 MEDIUMBLOB and MEDIUMTEXT – store up
to 16M bytes
 LONGBLOB and LONGTEXT – store up to 4G
bytes

Oracle interMedia Audio,
Image, and Video
 Oracle interMedia supports multimedia storage, retrieval,
and management of:
– BLOBs stored locally in Oracle8i onwards and containing audio,
image, or video data
– BFILEs, stored locally in operating system-specific file systems
and containing audio, image or video data
– URLs containing audio, image, or video data stored on any HTTP
server such as Oracle Application Server, Netscape Application
Server, Microsoft Internet Information Server, Apache HTTPD
server, and Spyglass servers
– Streaming audio or video data stored on specialized media
servers such as the Oracle Video Server

The Object Relational Multimedia
Domain Types in interMedia
 interMedia
provides the ORDAudio, ORDImage,
and ORDVideo object types and methods for:
– updateTime ORDSource attribute manipulation
– manipulating multimedia data source attribute
information
– extracting attributes from multimedia data
– getting and managing multimedia data from Oracle
interMedia, Web servers, and other servers
– performing a minimal set of manipulation operations on
multimedia data (images only)

Cont …
 The properties available are:
 ORDImage – the height, width, data size of the
on-disk image, file type, image type,compression
type, and MIME type
 ORDAudio – the format, encoding, number of
channels, sampling rate, sample size,compression
type, and audio duration
 ORDVideo – the format, frame size, frame
resolution, frame rate, video duration, number of
frames, compression type, number of colours, and
bit rate

Cont …
 Oracle also stores metadata including:
– source type, location, and source name
– MIME type and formatting information
– characteristics such as height and width of an
image, number of audio channels, video frame
rate, pay time, etc.

OO databases – e.g. Jasmine
 Jasmine is an Object-Oriented database and has an
application known as Studio is its development
environment
 It comes with a number of built in classes include
four multimedia classes:
– Picture -
– Image –
– Video –
– Audio -
 These come with manipulation and compression
facilities They also have been made to fit well
with Java Media Framework

conclusions
 At present you can not do much with MM data,
there are two reasons for this:
1. It is very large
– indexing on multimedia data is not reasonable nor is
storing a default value
– other retrieval may be slowed down
– transactions may be compromised
2. The properties are not well understood or
implementable in reasonable time
– what does it mean to say that one image is before
another in order therefore there are few operators in the
where clause that work

Cont ..
 At
the moment, there is no reason for putting
multimedia data into a relational database
– it just slows everything down
– and you can’t do very much
 You could use an object relational or object
oriented database
– now you can do more
– but the products are immature
– and everything will be slow

Cont …
 There are three main reasons for integrating
multimedia data with a database:
 1. Cataloguing the data
– a column for file names is good enough
 2. Decorating Reports
– The OLE approach works well here Otherwise a file
name column and a simple application for generating
the reports would do
 3. Web Applications
– Again a file name column is good enough

Lecture 3 multimedia databases

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