Data Accessor Pattern:
- Used to seperate data access complexity from application logic. Typically used in applications with a db backend. Changes in data representation will not affect application logic as long as application uses a generic set of access operations to retrieve data (etc: read,write,delete).
Active Domain Object Pattern:
- Sits in between the physical representation and the business logic. Encapsulates physical data representation in higher level domain objects. The data access can be encapsulated in a data accessor pattern.
Object Relational Map:
- Maps objects to relational databases. In other words, it is used to encapsulate physical data in logical objects. A typical mapping would map a table to a class, a row to an object and a column to an attribute.
- A one to one relationship between tables is mapped using a direct reference.
- A one to many could be an aggregation or an association. In an aggregation, one side owns the other one. In an association, one side is related to the other one. In an aggregation, all owned objects are automatically updated. In an aggregation, all related objects are just read automatically.
- A many to many is a bidirectional association.
“Words like 'vision' and 'dream' are back in currency. For long, they were inhabiting the manifestoes of political parties and the lexicon of the student who wanted to make a name in elocution. The common man did not believe in these words.
Now, suddenly he does. Many factors have contributed to this recharging of meaning. One is a President, who, by virtue of not being a regular politician, has caught the imagination of the nation. His dream of India becoming a superpower by 2020 has become the people's dream.
But between the idea and the reality falls a shadow, as the poet said. In a series of articles beginning with one penned by President A.P.J. Abdul Kalam himself, we do a reality-check on this dream. Experts ranging from Bharat Karnad and M.S. Swaminathan to K. Kasturirangan and Arun Shourie give their concrete proposals on how to turn these ideas into reality. So that dreams do not remain daydreams.
The 21st century belongs to the knowledge age, where acquisition, possession and application of knowledge are the most important resources. To India, knowledge is not new. Ancient India was an advanced knowledge society with a continual process of intellectual renaissance through inspiring contributions by saints of many faiths, philosophers, poets, scientists, astronomers and mathematicians. There existed great universities like Takshasila and Nalanda where students not only from India but also from far-off countries came to study diverse subjects. Many scholars have said that India culturally conquered and dominated China for 20 centuries without sending a single soldier across the border.
However, invasions and colonial rule destroyed these institutions and robbed them of their core competence. People were systematically degraded to lower levels of existence. By the time the British left, India was at its nadir. Now, it has the challenging task of rediscovering itself and become a knowledge superpower by 2020. For this India first needs to transform itself into a knowledge society. Let us see the genesis of such a society, its characteristics and how India can transform itself into a knowledge power.
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