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Revision 12498

Added by Aaron Marcuse-Kubitza almost 11 years ago

schemas/util.sql: diff(text, text): documented how to write a custom keys() function to match up rows using a subset of the columns (including a sample keys() function template)

View differences:

trunk/schemas/util.sql
1083 1083 
single_row: whether the tables consist of a single row, which should be
1084 1084 
	displayed side-by-side
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to match up rows using a subset of the columns, create a custom keys() function


  		




  
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which returns this subset as a record:


  		




  
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-- note that OUT parameters for the returned fields are *not* needed


  		




  
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CREATE OR REPLACE FUNCTION [schema].keys(value [schema].[base_type])


  		




  
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  RETURNS record AS


  		




  
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$BODY$


  		




  
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SELECT ($1.key_field_0, $1.key_field_1)


  		




  
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$BODY$


  		




  
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  LANGUAGE sql IMMUTABLE


  		




  
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  COST 100;


  		




  
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to run EXPLAIN on the FULL JOIN query:


  		




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# run this function


  		




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# look for a NOTICE containing the expanded query that it ran


  		












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