what is data independence exactly? give an example
Answer Posted / sravya
There are two types of data independence
1. Logical data independence: The ability to change the
logical (conceptual) schema without changing the External
schema (User View) is called logical data independence. For
example, the addition or removal of new entities,
attributes, or relationships to the conceptual schema should
be possible without having to change existing external
schemas or having to rewrite existing application programs.
2 Physical data independence: The ability to change the
physical schema without changing the logical schema is
called physical data independence. For example, a change to
the internal schema, such as using different file
organization or storage structures, storage devices, or
indexing strategy, should be possible without having to
change the conceptual or external schemas.
| Is This Answer Correct ? | 127 Yes | 11 No |
Post New Answer View All Answers
Using the relations and the rules set out in the notes under each relation, write statements to create the two sequence generators specified in the notes.
How to delete a column in an existing table?
Explain the use of indexes option in imp command.
How translate command is different from replace?
How to convert characters to times in oracle?
Hi this srilatha. I comlpeted my Oracle-hrms. can u provide me interview questions on Core hr, payroll,sshr,OLM etc..
Her departmandaki isçilerden empno' su ikinci sirada olan isçilerin empno, deptno, hiredate, sira_no bigilerini döndüren sorguyu yaziniz?
What are the various oracle database objects?
If youre unsure in which script a sys or system-owned object is created, but you know its in a script from a specific directory, what UNIX command from that directory structure can you run to find your answer?
What do database buffers contain?
Explain the use of grant option in imp command.
What is coalesce function?
How different is ms access and oracle?
What is where clause in oracle?
What is the meaning of recursive hints in oracle?