What are the purpose for having variable length records, Database Management System

Assignment Help:

What are the purpose for having variable length records? What kinds of separator characters are required for each?

Variable-Length Records - Variable-length records are those records that are of various sizes. A file may holds variable-length records in any of the subsequent situations:

• Records having variable length fields - In this case, the end-of-field symbol along with end-of-record symbol could be used as the separator characters.

• Records having repeating fields - In this case, the number of repetitions of repeating area can be used along with end-of-record symbol as the separator characters.

• Records having optional fields - In this case, the end-of-field symbol along with end-of-record symbol could be used as the separator characters.

• File containing records of various record types - In this case, a special field (or control field) can be prefixed with every record and end-of-record symbol could be used as the separator characters.

In each of the above situations either we can use end-of-record symbol or the length of every record can be prefixed at the starting of the record for the separation of the variable-length records.


Related Discussions:- What are the purpose for having variable length records

Explain the term- periodic recomputation, Explain the term- Periodic recomp...

Explain the term- Periodic recomputation Periodic recomputation:  Base values are often updated in bunches. Sometimes, it is possible to just recompute all derived attributes p

Differentiate between logical database design and physical, Differentiate b...

Differentiate between logical database design and physical database design. Show how this separation leads to data independence? Basis Logical Databas

What is a recursive relationship, Question: (a) Can a set of data requi...

Question: (a) Can a set of data requirements be correctly modelled by two or more different ER diagrams? Explain your answer. You may use a small example, if you think it will

Exclusive lock, Exclusive lock It is asked for by a transaction on...

Exclusive lock It is asked for by a transaction on a data item that it wants to update. No other transaction can put either a shared lock or an exclusive lock on a dat

Define partial, Partial Key : It is a group of attributes that can uniquel...

Partial Key : It is a group of attributes that can uniquely identify small entities and that are related to same base entity. It is sometime named as Discriminator.  Altern

To eliminate duplicate rows-data manipulation language, To eliminate duplic...

To eliminate duplicate rows (distinct operator)  Example: SELECT DISTINCT DEPTNO FROM EMP;

Writing a pl/sql program, Problem 1. Create a PL/SQL program to insert ...

Problem 1. Create a PL/SQL program to insert data into student table and display the details of the student having Reg.No 1010 Writing a PL/SQL program to Insert data

What is difference between truncate and delete, What is difference between ...

What is difference between TRUNCATE and DELETE? - Truncate can't be rolled back whereas Delete can be. - Truncate keeps the lock on table whereas Delete keeps the lock on ea

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd