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@@ -1,5 +1,7 @@
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 *SVN*
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+* [DOC] clear up some ambiguity with the way has_and_belongs_to_many creates the default join table name.  #7072 [jeremymcanally]
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+
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 * change_column accepts :default => nil. Skip column options for primary keys.  #6956, #7048 [dcmanges, Jeremy Kemper]
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 * MySQL, PostgreSQL: change_column_default quotes the default value and doesn't lose column type information.  #3987, #6664 [Jonathan Viney, manfred, altano@bigfoot.com]

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@@ -745,7 +745,13 @@ module ActiveRecord
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       # Associates two classes via an intermediate join table.  Unless the join table is explicitly specified as
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       # an option, it is guessed using the lexical order of the class names. So a join between Developer and Project
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-      # will give the default join table name of "developers_projects" because "D" outranks "P".
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+      # will give the default join table name of "developers_projects" because "D" outranks "P".  Note that this precedence
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+      # is calculated using the <tt><</tt> operator for <tt>String</tt>.  This means that if the strings are of different lengths, 
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+      # and the strings are equal when compared up to the shortest length, then the longer string is considered of higher
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+      # lexical precedence than the shorter one.  For example, one would expect the tables <tt>paper_boxes</tt> and <tt>papers</tt> 
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+      # to generate a join table name of <tt>papers_paper_boxes</tt> because of the length of the name <tt>paper_boxes</tt>,
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+      # but it in fact generates a join table name of <tt>paper_boxes_papers</tt>.  Be aware of this caveat, and use the 
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+      # custom <tt>join_table</tt> option if you need to.
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       #
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       # Deprecated: Any additional fields added to the join table will be placed as attributes when pulling records out through
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       # has_and_belongs_to_many associations. Records returned from join tables with additional attributes will be marked as