("oracle_why_image_indatabase", 2005) Oracle database provides a feature known as oracle Intermedia which enables easy and efficient management of images, audio and video data. ("Oracle", 2005) This helps programmers in multimedia application development. Oracle 10g also addresses issues such as security, backup/recovery, extensibility and flexibility. ("oracle_why_image_indatabase", 2005) It reduces the response time and hence reduces the operation cost as well.
Storing images in file system allows does not allow selective access to images in the directory. Individual users can access all or none of the images in the file system, which is not desired and this proves a threat to the database. ("oracle_why_image_indatabase",2005) In traditional file systems the images have to be backed up on regular basis, which is not so in database storage. One single backup program is required for day to day backup and also only one program is required for recovery. Conversion of images form one format to another is also made possible in this storage procedure.
Oracle, as we all know is a database management system that is Object Relational in nature. This allows oracle to store images in addition to normal data in the database. With the support provided for Binary Large Object's, it is possible to store complex objects in the database. ("sdsu.edu", 1997) "BLOB stored images have an object relational type known as ORDImgB, while BFILE stored images have an object relational type known as ORDImgF."("sdsu.edu", 1997) A locator is stored in the row and the actual image is stored in other table space. To store a binary image in the database define a column in the table with BLOB data type. All movie files, images form scanners; large mpeg files can be stored in BLOB column. A table containing BLOB data type is as follows
CREATE TABLE test_table (
Image BLOB); ("expertanswercenter", 2005)
The images stored in database are linked with metadata. "Metadata in Greek literally means data about data." ("Wikipedia", 2005) It is information that describes another set of data and stored in a central location to help organizations standardize their data. The images are stored in a row in the table which contains alphanumeric columns.
Storage space required for image data depends on how the image was captured. Database applications such as geographic information systems, imaging, workflow etc require the storing and retrieval of these images which is facilitated by data cartridges. "A data cartridge is the mechanism by which clients, application-specific servers, and database servers can be easily and reliably extended."("sdsu.edu",1997) Storing, retrieval, compressing, decompressing, reformatting and a few data manipulation services such as scaling and cropping are achieved through data cartridge mechanism. ("sdsu.edu",1997)
Accessing the attributes within a complex object is possible through the dot notation. Accessing images to perform various functions such as select, update or delete can be performed with the following syntax statement.
"SELECT table_alias.variable.data_attribute FROM table_name table_alias" ("sdsu.edu", 1997) It is also possible to extract other properties such as the file format, content format, height and width in pixels, compression format and