Refresher/m/SQL/Basic Concepts

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