What is system log, Database Management System

Assignment Help:

What is system log?  What are the entries?      

Ans:  The system log that is generally written on stable storage contains the redundant data required to recover from volatile storage failures and as well from errors discovered by the transaction or the database system. System log is as well known as log and has sometimes been called the DBMS journal. It consists of the following entries (also known as log records):

a. [start_transaction, T]: Points out that transaction T has started execution.

b. [write_item, T, X, old_value, new_value]: Points out that transaction T has changed the value of database item X from old_value to new_value.

c. [read_item, T, X]: Points out that transaction T has read the value of database item X.

d. [commit, T]: Points out that transaction T has completed successfully, and affirms that its effect can be committed (recorded permanently) to the database.

e. [abort, T]: Points out that transaction T has been aborted.


Related Discussions:- What is system log

Convert the er - diagram into a relational database, Convert the following ...

Convert the following ER - diagram (Entity Relationship Diagram) into a relational database (the primary keys are underlined):       Ans:  The relational database schema f

Assign, #quesDefine a job scheduling strategy that will meet business requi...

#quesDefine a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pi

School portal design and development, Project Description: This is going...

Project Description: This is going to be a School portal to handle each activities in school such as, School fees payment, online registration and every other payment, course re

Why containment is important in oosystems, Why containment is important in ...

Why containment is important in oosystems? Containment is an significant concept in oosystems because it allows dissimilar users to view data at different granularities.

Define object-oriented database, Question : Object-Oriented Database (O...

Question : Object-Oriented Database (OODM) is defined as a logical data model that captures the semantics of objects supported in object-oriented programming. An Object-Oriente

Write short notes on schema diagram, Write short notes on Schema diagram. ...

Write short notes on Schema diagram. A database schema along with primary key and foreign key dependencies can be depicted pictorially by schema diagram. Every relation appears

What is storage manager, What is storage manager? A storage manager is ...

What is storage manager? A storage manager is a program module that gives the interface among the low level data keeps in a database and the application programs and queries su

How the time stamps are implemented, How the time stamps are implemented ...

How the time stamps are implemented Use the value of the system clock as the time stamp. That is a transaction's time stamp is equivalent to the value of the clock when the tra

Higher software development cost, Drawbacks of Data Distribution: The prim...

Drawbacks of Data Distribution: The primary drawbacks of distributed database systems are the added complexity needed to ensure proper coordination between the sites. This increas

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