49 lines
1.5 KiB
Ruby
49 lines
1.5 KiB
Ruby
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## This patch is from rails 4.2-stable. Remove it when 4.2.6 is released
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## https://github.com/rails/rails/issues/21108
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module ActiveRecord
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module ConnectionAdapters
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class AbstractMysqlAdapter < AbstractAdapter
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# SHOW VARIABLES LIKE 'name'
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def show_variable(name)
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variables = select_all("select @@#{name} as 'Value'", 'SCHEMA')
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variables.first['Value'] unless variables.empty?
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rescue ActiveRecord::StatementInvalid
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nil
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end
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# MySQL is too stupid to create a temporary table for use subquery, so we have
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# to give it some prompting in the form of a subsubquery. Ugh!
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def subquery_for(key, select)
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subsubselect = select.clone
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subsubselect.projections = [key]
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subselect = Arel::SelectManager.new(select.engine)
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subselect.project Arel.sql(key.name)
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# Materialized subquery by adding distinct
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# to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on'
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subselect.from subsubselect.distinct.as('__active_record_temp')
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end
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end
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end
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end
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module ActiveRecord
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module ConnectionAdapters
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class MysqlAdapter < AbstractMysqlAdapter
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ADAPTER_NAME = 'MySQL'.freeze
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# Get the client encoding for this database
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def client_encoding
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return @client_encoding if @client_encoding
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result = exec_query(
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"select @@character_set_client",
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'SCHEMA')
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@client_encoding = ENCODINGS[result.rows.last.last]
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end
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end
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end
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end
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