Database Administration Questions

Immutable classes are Java classes whose objects can not be modified once created. Any modification in Immutable object result in new object. For example is String is immutable in Java. Mostly Immutable are also final in Java, in order to prevent sub class from overriding methods in Java which can compromise Immutability. You can achieve same functionality by making member as non final but private and not modifying them except in constructor.

Biodegradable substances can be broken down into simpler, harmless substances in nature with due course of time by the biological process such as action of microbes. They can be recycled as a part of food chain.

Here, Leather bags are biodegradable.

Work breakdown structure is an important tool for project scope management.

Project Scope Management refers to the set of processes that ensure a project’s scope is accurately defined and mapped. Scope Management techniques enable project managers and supervisors to allocate just the right amount of work necessary to successfully complete a project—concerned primarily with controlling what is and what is not part of the project’s scope.

A relational database is a digital database based on the relational model of data, a database structured to recognize relations between stored items of information. A software system used to maintain relational databases is a relational database management system.

Computer database in which all data is stored in Relations which (to the user) are tables with rows and columns. Each table is composed of records (called Tuples) and each record is identified by a field (attribute) containing a unique value. Every table shares at least one field with another table in 'one to one,' 'one to many,' or 'many to many' relationships. These relationships allow the database user to access the data in almost an unlimited number of ways, and to combine the tables as building blocks to create complex and very large databases.

Sound is a mechanical vibration and needs a medium for propagation. The higher the density of the medium, the faster the sound travels. So, sound cannot travel through vacuum.

As the sound travels faster in solids than liquids and gases, sound travels faster in the glass than Air and water.