Interview Notes - Page 9

Logical and Physical Data Independence

Data independence is the ability to change a schema at one level without changing the level above. Physical independence is easy to achieve; logical i...

DBMS

Three Level Architecture and Data Abstraction

The ANSI-SPARC architecture separates a database into external, conceptual and internal levels. That separation is what makes data abstraction and dat...

DBMS

Database Users and the Role of the DBA

A database system serves naive users, application programmers, sophisticated users and specialised users, and is run by a database administrator whose...

DBMS

Advantages and Limitations of a DBMS

A DBMS buys controlled redundancy, enforced integrity, sharing, security, recovery and independence. It charges for them in cost, complexity, hardware...

DBMS

File System versus DBMS

The file based approach fails on redundancy, inconsistency, isolation, atomicity, concurrency, security and integrity. Each failure maps to one specif...

DBMS

What a DBMS Is and Why It Exists

A DBMS is the software layer between users and stored data. It exists to give many users controlled, concurrent, recoverable and consistent access to...

DBMS

Data, Information and Databases

Data is raw recorded fact, information is data placed in context, and a database is an organised, shared, self describing collection of related data...

Java

JDBC Transactions and Batch Operations

A transaction makes several statements succeed or fail together, and batching turns many round trips into one.

Java

PreparedStatement and SQL Injection Prevention in Java

Concatenating input into SQL lets a caller rewrite your query. Bound parameters make that structurally impossible.

Java

Immutability and Defensive Copying in Java

An immutable object cannot change after construction, which removes whole categories of bug at the cost of a little copying.

Java

Sealed Classes and Pattern Matching in Java

A sealed type names exactly which types may extend it, which lets the compiler check that a pattern switch covers every case.

Java

Garbage Collection in Java

The collector reclaims objects that can no longer be reached. Understanding reachability explains both leaks and pauses.