NEB Class 12 • Computer Science • DBMS • Concept Guide

Centralized & Distributed Databases & Database Security: NEB Class 12 Computer Guide

Master Centralized and Distributed Databases and Database Security through clear concepts, representations, a reliable answer method and exam-focused practice.

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Concepts · Worked reasoning · NEB practice

Quick answer: A centralized database is managed mainly at one site, while a distributed database coordinates data across networked locations. Design trades consistency, availability, latency, autonomy and failure handling; security requires identity, authorization, encryption, auditing and recovery.

Core concept

What Centralized and Distributed Databases and Database Security means physically

A centralized database is managed mainly at one site, while a distributed database coordinates data across networked locations. Design trades consistency, availability, latency, autonomy and failure handling; security requires identity, authorization, encryption, auditing and recovery.

Compare placement and replication→transaction/consistency model→network and failure assumptions→access control→backup and disaster recovery.

The institutional reference gives the wider physical model; the CDC curriculum determines the NEB boundary.

Worked checkpoint with interpretation

A bank may replicate selected data across sites for availability, but transactions need coordination so concurrent updates do not create contradictory balances.

Do not stop at the number. State what the sign, ratio, spacing, frequency or direction means. A common error is Assuming distributed always means faster or safer, confusing backup with replication, granting broad privileges, or transmitting sensitive records without protection.

NEB answer method

Model → evidence → equation → check

First identify the system and what the question asks. Label the diagram, apparatus or reaction with SI quantities, then state the principle before selecting an equation. Solve symbolically where possible and check units, limiting cases and chemical or physical meaning.

StageQuestionEvidence
ModelWhat is idealised?Assumption stated
RepresentationWhich diagram fits?Labels or balanced equation
CalculationWhich relation follows?Symbols then SI values
EvaluationDoes it make sense?Unit, sign and trend check

Make the idea concrete in Nepal

Connect the model to a school laboratory, household technology, health, environment, energy or local material. The example should clarify the science rather than merely mention a place. Compare a prediction with an observation and record uncertainty.

Review the NEB Class 12 Computer Science revision roadmap and the complete Computer Science guide. For online or physical tuition, call 9846662070.

Questions students ask about Centralized and Distributed Databases and Database Security

What is the central idea of Centralized and Distributed Databases and Database Security?

A centralized database is managed mainly at one site, while a distributed database coordinates data across networked locations. Design trades consistency, availability, latency, autonomy and failure handling; security requires identity, authorization, encryption, auditing and recovery.

Which equation should I remember?

Compare placement and replication→transaction/consistency model→network and failure assumptions→access control→backup and disaster recovery.

How should I begin a numerical?

Draw the situation, list known quantities in SI units, choose the governing relation symbolically, substitute once and finish with a unit and reasonableness check.

What is a common exam mistake?

Assuming distributed always means faster or safer, confusing backup with replication, granting broad privileges, or transmitting sensitive records without protection.

How can I practise this topic?

Alternate one concept explanation, one diagram and two numericals. Revisit errors after a day instead of only rereading the solution.

Where can I get tuition support?

For online or physical KTM Tuition classes, call 9846662070. After Grade 12, the MKS Education panel below gives preparation and pre-counselling contacts.

Frequently asked questions

References and next steps

Scope checked against CDC Nepal; concept support from an institutional reference and OpenStax Science. Continue with the Centralized and Distributed Databases and Database Security cluster.

NEB +2 tuition support

Ask about online or physical tuition

For focused Class 11 and Class 12 subject tuition, lesson clarification, worked-example practice and exam preparation, call 9846662070. Class mode, timetable, teacher availability and fees should be confirmed directly before enrolment.

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