134 lines
3.7 KiB
Ruby
134 lines
3.7 KiB
Ruby
# Adds support for WITH statements when using PostgreSQL. The code here is taken
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# from https://github.com/shmay/ctes_in_my_pg which at the time of writing has
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# not been pushed to RubyGems. The license of this repository is as follows:
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#
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# The MIT License (MIT)
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#
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# Copyright (c) 2012 Dan McClain
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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module ActiveRecord
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class Relation
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class Merger # :nodoc:
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def normal_values
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NORMAL_VALUES + [:with]
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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::Querying
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delegate :with, to: :all
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end
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module ActiveRecord
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class Relation
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# WithChain objects act as placeholder for queries in which #with does not have any parameter.
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# In this case, #with must be chained with #recursive to return a new relation.
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class WithChain
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def initialize(scope)
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@scope = scope
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end
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# Returns a new relation expressing WITH RECURSIVE
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def recursive(*args)
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@scope.with_values += args
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@scope.recursive_value = true
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@scope
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end
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end
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def with_values
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@values[:with] || []
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end
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def with_values=(values)
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raise ImmutableRelation if @loaded
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@values[:with] = values
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end
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def recursive_value=(value)
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raise ImmutableRelation if @loaded
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@values[:recursive] = value
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end
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def recursive_value
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@values[:recursive]
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end
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def with(opts = :chain, *rest)
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if opts == :chain
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WithChain.new(spawn)
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elsif opts.blank?
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self
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else
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spawn.with!(opts, *rest)
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end
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end
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def with!(opts = :chain, *rest) # :nodoc:
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if opts == :chain
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WithChain.new(self)
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else
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self.with_values += [opts] + rest
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self
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end
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end
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def build_arel(aliases)
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arel = super
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build_with(arel) if @values[:with]
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arel
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end
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def build_with(arel)
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with_statements = with_values.flat_map do |with_value|
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case with_value
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when String
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with_value
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when Hash
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with_value.map do |name, expression|
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case expression
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when String
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select = Arel::Nodes::SqlLiteral.new "(#{expression})"
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when ActiveRecord::Relation, Arel::SelectManager
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select = Arel::Nodes::SqlLiteral.new "(#{expression.to_sql})"
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end
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Arel::Nodes::As.new Arel::Nodes::SqlLiteral.new("\"#{name}\""), select
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end
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when Arel::Nodes::As
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with_value
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end
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end
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unless with_statements.empty?
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if recursive_value
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arel.with :recursive, with_statements
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else
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arel.with with_statements
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end
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end
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end
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end
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end
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