1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
# frozen-string-literal: true
module Sequel
module Plugins
# The subset_conditions plugin creates an additional *_conditions method
# for every `subset`, `where`, and `exclude` method call in a dataset_module
# block. This method returns the filter conditions, which can be useful if
# you want to use the conditions for a separate filter or combine them with OR.
# It also supports where_all and where_any dataset_module methods for
# combining multiple dataset method filters with AND or OR.
#
# Usage:
#
# # Add subset_conditions in the Album class
# Album.plugin :subset_conditions
#
# Album.dataset_module do
# # This will now create a published_conditions method
# where :published, published: true
#
# # This will now create a not_bad_conditions method
# exclude :not_bad, :bad
#
# # This will create good_and_available and
# # good_and_available_conditions methods
# where_all :good_and_available, :published, :not_bad
#
# # This will create good_or_available and
# # good_or_available_conditions methods
# where_any :good_or_available, :published, :not_bad
# end
#
# Album.where(Album.published_conditions).sql
# # SELECT * FROM albums WHERE (published IS TRUE)
#
# Album.exclude(Album.published_conditions).sql
# # SELECT * FROM albums WHERE (published IS NOT TRUE)
#
# Album.where(Album.published_conditions | {ready: true}).sql
# # SELECT * FROM albums WHERE ((published IS TRUE) OR (ready IS TRUE))
#
# Album.good_and_available.sql
# SELECT * FROM albums WHERE ((published IS TRUE) AND NOT bad)
#
# Album.good_or_available.sql
# SELECT * FROM albums WHERE ((published IS TRUE) OR NOT bad)
module SubsetConditions
def self.apply(model, &block)
model.instance_exec do
@dataset_module_class = Class.new(@dataset_module_class) do
Sequel.set_temp_name(self){"#{model.name}::@dataset_module_class(SubsetConditions)"}
include DatasetModuleMethods
end
end
end
module DatasetModuleMethods
# Also create a method that returns the conditions the filter uses.
def where(name, *args, &block)
super
cond = args
cond = cond.first if cond.size == 1
define_method(:"#{name}_conditions"){filter_expr(cond, &block)}
end
# Also create a method that returns the conditions the filter uses.
def exclude(name, *args, &block)
super
cond = args
cond = cond.first if cond.size == 1
define_method(:"#{name}_conditions"){Sequel.~(filter_expr(cond, &block))}
end
# Create a method that combines filters from already registered
# dataset methods, and filters for rows where all of the conditions
# are satisfied.
#
# Employee.dataset_module do
# where :active, active: true
# where :started, Sequel::CURRENT_DATE <= :start_date
# where_all(:active_and_started, :active, :started)
# end
#
# Employee.active_and_started.sql
# # SELECT * FROM employees WHERE ((active IS TRUE) AND (CURRENT_DATE <= start_date))
def where_all(name, *args)
_where_any_all(:&, name, args)
end
# Create a method that combines filters from already registered
# dataset methods, and filters for rows where any of the conditions
# are satisfied.
#
# Employee.dataset_module do
# where :active, active: true
# where :started, Sequel::CURRENT_DATE <= :start_date
# where_any(:active_or_started, :active, :started)
# end
#
# Employee.active_or_started.sql
# # SELECT * FROM employees WHERE ((active IS TRUE) OR (CURRENT_DATE <= start_date))
def where_any(name, *args)
_where_any_all(:|, name, args)
end
private
if RUBY_VERSION >= '2'
# Backbone of #where_any and #where_all
def _where_any_all(meth, name, args)
ds = model.dataset
# #bind used here because the dataset module may not yet be included in the model's dataset
where(name, Sequel.send(meth, *args.map{|a| self.instance_method(:"#{a}_conditions").bind(ds).call}))
end
else
# Cannot bind module method to arbitrary objects in Ruby 1.9.
# :nocov:
def _where_any_all(meth, name, args)
ds = model.dataset.clone
ds.extend(self)
where(name, Sequel.send(meth, *args.map{|a| ds.send(:"#{a}_conditions")}))
end
# :nocov:
end
end
end
end
end
|
