Refresher/SQL/Basic Concepts

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Presentation

Introduction
Introduction
Basic Concepts
Most Frequently Asked
Most Frequently Asked
List of Topics
List of Topics
   
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This presentation was made possible by Wikiversal/WikiverSuite, which is made possible by your donation. Thank you for your support.
Most Frequently Asked
Most Frequently Asked
 Constraint: an input filter
 
 Denormalizing: performance improvement through reduction in number of joins needed for data processing
 
 Group by and order by clauses: expensive due to creation of temporary tables
 
 Indexes' tradeoffs: faster retrieval, slower updates
 
 Join: a logical connection between two tables
 
 Normalizing: eliminating redundant information and making it easier for future updates
 
 Primary key: a combination of columns which uniquely specify a row
 
 Trigger: the code automatically executed in response to certain table events
 
 Where vs having: where is a restriction and having is a filter
 
 Wildcard: % using LIKE
 
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