Define partial key and primary key, Database Management System

Assignment Help:

Define Partial Key and Primary Key

A partial key, also known as discriminator, is the set of attributes which can uniquely identify weak entities that are related to similar owner entity. Primary key is a unique key but not comprise null values. An entity set can comprise at most one primary key.

Related Discussions:- Define partial key and primary key

Determine the subsystem design issue, Determine the Other System Design Iss...

Determine the Other System Design Issue How to realise subsystems; through hardware or software? How is object model mapped on chosen hardware software? Mapping

Illustrate the diagram - association as a cache, Association as a cache ...

Association as a cache This association must be updated when any new element is added to it, but testing for overlap using association is more efficient. Figure:

Describe the host language, Describe the host language? Host Language:...

Describe the host language? Host Language: You could write applications along with SQL statements embedded inside a host language. The SQL statements give the database inter

Describe physical data independence, Describe Physical Data independence ? ...

Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter

RDBMS, what is RDBMS? how it works? good example.

what is RDBMS? how it works? good example.

Develop a database design , A practice called Perfect Pets provides private...

A practice called Perfect Pets provides private health care for domestic pets throughout America. This service is provided through various clinics located in the main cities of Ame

Explain tuple variable, Define tuple variable? Tuple variables are used...

Define tuple variable? Tuple variables are used for comparing two tuples in the same relation. The tuple variables are explained in the from clause by way of the as clause.

Explain the dynamic hashing techniques, Explain the Dynamic Hashing Techniq...

Explain the Dynamic Hashing Techniques There are two methods in it: extendible hashing - stores an access structure in addition to the file, and therefore is somewhat identica

What are the properties of transaction, What are the properties of transact...

What are the properties of transaction? There are three properties of transactions :- A) Atomicity B) Consistency C) Isolation

Object-based models - data models, Object-based Models: Use objects as key ...

Object-based Models: Use objects as key data representation components . Examples:- Entity-Relationship Model: It is a collection of real world objects known as entitie

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages