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# frozen-string-literal: true
#
# This adds the following dataset methods:
#
# and :: alias for where
# exclude_where :: alias for exclude
# interval :: Returns max - min, using a single query
# range :: Returns min..max, using a single query
#
# It is only recommended to use this for backwards compatibility.
#
# You can load this extension into specific datasets:
#
# ds = DB[:table]
# ds = ds.extension(:sequel_4_dataset_methods)
#
# Or you can load it into all of a database's datasets, which
# is probably the desired behavior if you are using this extension:
#
# DB.extension(:sequel_4_dataset_methods)
#
# Related module: Sequel::Sequel4DatasetMethods
#
module Sequel
module Sequel4DatasetMethods
# Alias for where.
def and(*cond, &block)
where(*cond, &block)
end
# Alias for exclude.
def exclude_where(*cond, &block)
exclude(*cond, &block)
end
# Returns the interval between minimum and maximum values for the given
# column/expression. Uses a virtual row block if no argument is given.
#
# DB[:table].interval(:id) # SELECT (max(id) - min(id)) FROM table LIMIT 1
# # => 6
# DB[:table].interval{function(column)} # SELECT (max(function(column)) - min(function(column))) FROM table LIMIT 1
# # => 7
def interval(column=(no_arg = true), &block)
column = Sequel.virtual_row(&block) if no_arg
if loader = cached_placeholder_literalizer(:_interval_loader) do |pl|
arg = pl.arg
aggregate_dataset.limit(1).select((SQL::Function.new(:max, arg) - SQL::Function.new(:min, arg)).as(:interval))
end
loader.get(column)
else
aggregate_dataset.get{(max(column) - min(column)).as(:interval)}
end
end
# Returns a +Range+ instance made from the minimum and maximum values for the
# given column/expression. Uses a virtual row block if no argument is given.
#
# DB[:table].range(:id) # SELECT max(id) AS v1, min(id) AS v2 FROM table LIMIT 1
# # => 1..10
# DB[:table].interval{function(column)} # SELECT max(function(column)) AS v1, min(function(column)) AS v2 FROM table LIMIT 1
# # => 0..7
def range(column=(no_arg = true), &block)
column = Sequel.virtual_row(&block) if no_arg
r = if loader = cached_placeholder_literalizer(:_range_loader) do |pl|
arg = pl.arg
aggregate_dataset.limit(1).select(SQL::Function.new(:min, arg).as(:v1), SQL::Function.new(:max, arg).as(:v2))
end
loader.first(column)
else
aggregate_dataset.select{[min(column).as(v1), max(column).as(v2)]}.first
end
if r
(r[:v1]..r[:v2])
end
end
end
Dataset.register_extension(:sequel_4_dataset_methods, Sequel4DatasetMethods)
end
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