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

State the data flow diagram of functional model, State the data flow diagra...

State the data flow diagram of functional model Any action initiated by transition in the state diagram can be extended into an entire data flow diagram in functional model. Th

Define single valued and multivalued attributes, Define single valued and m...

Define single valued and multivalued attributes.  Single valued attributes: attributes with a single value for a particular entity are known as single valued attributes.   M

What are the functions of an accumulator, What are the functions of an accu...

What are the functions of an accumulator? The accumulator is the register associated with the ALU operations and sometimes I/O operations. It is an integral part of ALU. It hol

What is dml compiler, What is DML compiler? DML Compiler: Translates DM...

What is DML compiler? DML Compiler: Translates DML statements in a query language within low level instructions understandable through the query evaluation engine. Attempts to

Data models, why older data models are being replaced by new data models....

why older data models are being replaced by new data models.

Benefits and drawbacks of heap files, Benefits of heap files 1.   This i...

Benefits of heap files 1.   This is a easy file Organisation method. 2.   Insertion is somehow capable. 3.   Good for bulk-loading data into a table. 4.   Best if file

Define blocks, Define blocks? The database system resides eternally on ...

Define blocks? The database system resides eternally on non-volatile storage, and is into fixed-length storage units known as blocks.

Differance between internal and external schema, Differance between interna...

Differance between internal and external schema? Internal and external schema: Internal Schema • Describes the physical storage structure • Uses a physical data model External

Shared lock or read lock, Shared lock or Read Lock It is requested ...

Shared lock or Read Lock It is requested by a transaction that needs to just read the value of data item. A shared lock on a data item does not permit an exclusive lock

What is the function of sql server agent windows service, What is the funct...

What is the function of SQL Server Agent Windows service? - It's a Windows service that handles tasks scheduled within SQL Server environment. These tasks are also known as job

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