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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
|
require 'bigdecimal'
require 'date'
require 'arel/visitors/reduce'
module Arel
module Visitors
class ToSql < Arel::Visitors::Reduce
##
# This is some roflscale crazy stuff. I'm roflscaling this because
# building SQL queries is a hotspot. I will explain the roflscale so that
# others will not rm this code.
#
# In YARV, string literals in a method body will get duped when the byte
# code is executed. Let's take a look:
#
# > puts RubyVM::InstructionSequence.new('def foo; "bar"; end').disasm
#
# == disasm: <RubyVM::InstructionSequence:foo@<compiled>>=====
# 0000 trace 8
# 0002 trace 1
# 0004 putstring "bar"
# 0006 trace 16
# 0008 leave
#
# The `putstring` bytecode will dup the string and push it on the stack.
# In many cases in our SQL visitor, that string is never mutated, so there
# is no need to dup the literal.
#
# If we change to a constant lookup, the string will not be duped, and we
# can reduce the objects in our system:
#
# > puts RubyVM::InstructionSequence.new('BAR = "bar"; def foo; BAR; end').disasm
#
# == disasm: <RubyVM::InstructionSequence:foo@<compiled>>========
# 0000 trace 8
# 0002 trace 1
# 0004 getinlinecache 11, <ic:0>
# 0007 getconstant :BAR
# 0009 setinlinecache <ic:0>
# 0011 trace 16
# 0013 leave
#
# `getconstant` should be a hash lookup, and no object is duped when the
# value of the constant is pushed on the stack. Hence the crazy
# constants below.
#
# `matches` and `doesNotMatch` operate case-insensitively via Visitor subclasses
# specialized for specific databases when necessary.
#
WHERE = ' WHERE ' # :nodoc:
SPACE = ' ' # :nodoc:
COMMA = ', ' # :nodoc:
GROUP_BY = ' GROUP BY ' # :nodoc:
ORDER_BY = ' ORDER BY ' # :nodoc:
WINDOW = ' WINDOW ' # :nodoc:
AND = ' AND ' # :nodoc:
DISTINCT = 'DISTINCT' # :nodoc:
def initialize connection
@connection = connection
@schema_cache = connection.schema_cache
@quoted_tables = {}
@quoted_columns = {}
end
private
def visit_Arel_Nodes_DeleteStatement o, collector
collector << "DELETE FROM "
collector = visit o.relation, collector
if o.wheres.any?
collector << " WHERE "
inject_join o.wheres, collector, AND
else
collector
end
end
# FIXME: we should probably have a 2-pass visitor for this
def build_subselect key, o
stmt = Nodes::SelectStatement.new
core = stmt.cores.first
core.froms = o.relation
core.wheres = o.wheres
core.projections = [key]
stmt.limit = o.limit
stmt.orders = o.orders
stmt
end
def visit_Arel_Nodes_UpdateStatement o, collector
if o.orders.empty? && o.limit.nil?
wheres = o.wheres
else
wheres = [Nodes::In.new(o.key, [build_subselect(o.key, o)])]
end
collector << "UPDATE "
collector = visit o.relation, collector
values = false
unless o.values.empty?
values = true
collector << " SET "
collector = inject_join o.values, collector, ", "
end
unless wheres.empty?
collector << " WHERE "
collector = inject_join wheres, collector, " AND "
end
collector
end
def visit_Arel_Nodes_InsertStatement o, collector
collector << "INSERT INTO "
collector = visit o.relation, collector
if o.columns.any?
collector << " (#{o.columns.map { |x|
quote_column_name x.name
}.join ', '})"
end
maybe_visit o.values, collector
end
def visit_Arel_Nodes_Exists o, collector
collector << "EXISTS ("
collector = visit(o.expressions, collector) << ")"
if o.alias
collector << " AS "
visit o.alias, collector
else
collector
end
end
def visit_Arel_Nodes_Casted o, collector
collector << quoted(o.val, o.attribute).to_s
end
def visit_Arel_Nodes_Quoted o, collector
collector << quoted(o.expr, nil).to_s
end
def visit_Arel_Nodes_True o, collector
collector << "TRUE"
end
def visit_Arel_Nodes_False o, collector
collector << "FALSE"
end
def table_exists? name
@schema_cache.table_exists? name
end
def column_for attr
return unless attr
name = attr.name.to_s
table = attr.relation.table_name
return nil unless table_exists? table
column_cache(table)[name]
end
def column_cache(table)
@schema_cache.columns_hash(table)
end
def visit_Arel_Nodes_Values o, collector
collector << "VALUES ("
collector << o.expressions.zip(o.columns).map { |value, attr|
if Nodes::SqlLiteral === value
value
else
quote(value, attr && column_for(attr))
end
}.join(', ')
collector << ")"
end
def visit_Arel_Nodes_SelectStatement o, collector
if o.with
collector = visit o.with, collector
collector << SPACE
end
collector = o.cores.inject(collector) { |c,x|
visit_Arel_Nodes_SelectCore(x, c)
}
unless o.orders.empty?
collector << SPACE
collector << ORDER_BY
len = o.orders.length - 1
o.orders.each_with_index { |x, i|
collector = visit(x, collector)
collector << COMMA unless len == i
}
end
collector = maybe_visit o.limit, collector
collector = maybe_visit o.offset, collector
collector = maybe_visit o.lock, collector
collector
end
def visit_Arel_Nodes_SelectCore o, collector
collector << "SELECT"
if o.top
collector << " "
collector = visit o.top, collector
end
if o.set_quantifier
collector << " "
collector = visit o.set_quantifier, collector
end
unless o.projections.empty?
collector << SPACE
len = o.projections.length - 1
o.projections.each_with_index do |x, i|
collector = visit(x, collector)
collector << COMMA unless len == i
end
end
if o.source && !o.source.empty?
collector << " FROM "
collector = visit o.source, collector
end
unless o.wheres.empty?
collector << WHERE
len = o.wheres.length - 1
o.wheres.each_with_index do |x, i|
collector = visit(x, collector)
collector << AND unless len == i
end
end
unless o.groups.empty?
collector << GROUP_BY
len = o.groups.length - 1
o.groups.each_with_index do |x, i|
collector = visit(x, collector)
collector << COMMA unless len == i
end
end
if o.having
collector << " "
collector = visit(o.having, collector)
end
unless o.windows.empty?
collector << WINDOW
len = o.windows.length - 1
o.windows.each_with_index do |x, i|
collector = visit(x, collector)
collector << COMMA unless len == i
end
end
collector
end
def visit_Arel_Nodes_Bin o
visit o.expr
end
def visit_Arel_Nodes_Distinct o, collector
collector << DISTINCT
end
def visit_Arel_Nodes_DistinctOn o, collector
raise NotImplementedError, 'DISTINCT ON not implemented for this db'
end
def visit_Arel_Nodes_With o
"WITH #{o.children.map { |x| visit x }.join(', ')}"
end
def visit_Arel_Nodes_WithRecursive o, collector
collector << "WITH RECURSIVE "
inject_join o.children, collector, ', '
end
def visit_Arel_Nodes_Union o, collector
collector << "( "
infix_value(o, collector, " UNION ") << " )"
end
def visit_Arel_Nodes_UnionAll o, collector
collector << "( "
infix_value(o, collector, " UNION ALL ") << " )"
end
def visit_Arel_Nodes_Intersect o, collector
collector << "( "
infix_value(o, collector, " INTERSECT ") << " )"
end
def visit_Arel_Nodes_Except o, collector
collector << "( "
infix_value(o, collector, " EXCEPT ") << " )"
end
def visit_Arel_Nodes_NamedWindow o, collector
collector << quote_column_name(o.name)
collector << " AS "
visit_Arel_Nodes_Window o, collector
end
def visit_Arel_Nodes_Window o, collector
collector << "("
if o.orders.any?
collector << "ORDER BY "
collector = inject_join o.orders, collector, ", "
end
if o.framing
collector = visit o.framing, collector
end
collector << ")"
end
def visit_Arel_Nodes_Rows o, collector
if o.expr
collector << "ROWS "
visit o.expr, collector
else
collector << "ROWS"
end
end
def visit_Arel_Nodes_Range o, collector
if o.expr
collector << "RANGE "
visit o.expr, collector
else
collector << "RANGE"
end
end
def visit_Arel_Nodes_Preceding o, collector
collector = if o.expr
visit o.expr, collector
else
collector << "UNBOUNDED"
end
collector << " PRECEDING"
end
def visit_Arel_Nodes_Following o, collector
collector = if o.expr
visit o.expr, collector
else
collector << "UNBOUNDED"
end
collector << " FOLLOWING"
end
def visit_Arel_Nodes_CurrentRow o, collector
collector << "CURRENT ROW"
end
def visit_Arel_Nodes_Over o
case o.right
when nil
"#{visit o.left} OVER ()"
when Arel::Nodes::SqlLiteral
"#{visit o.left} OVER #{visit o.right}"
when String, Symbol
"#{visit o.left} OVER #{quote_column_name o.right.to_s}"
else
"#{visit o.left} OVER #{visit o.right}"
end
end
def visit_Arel_Nodes_Having o, collector
collector << "HAVING "
visit o.expr, collector
end
def visit_Arel_Nodes_Offset o, collector
collector << "OFFSET "
visit o.expr, collector
end
def visit_Arel_Nodes_Limit o, collector
collector << "LIMIT "
visit o.expr, collector
end
# FIXME: this does nothing on most databases, but does on MSSQL
def visit_Arel_Nodes_Top o, collector
collector
end
def visit_Arel_Nodes_Lock o, collector
visit o.expr, collector
end
def visit_Arel_Nodes_Grouping o, collector
collector << "("
visit(o.expr, collector) << ")"
end
def visit_Arel_SelectManager o, collector
collector << "(#{o.to_sql.rstrip})"
end
def visit_Arel_Nodes_Ascending o, collector
visit(o.expr, collector) << " ASC"
end
def visit_Arel_Nodes_Descending o, collector
visit(o.expr, collector) << " DESC"
end
def visit_Arel_Nodes_Group o, collector
visit o.expr, collector
end
def visit_Arel_Nodes_NamedFunction o, collector
collector << o.name
collector << "("
collector << "DISTINCT " if o.distinct
collector = inject_join(o.expressions, collector, ", ") << ")"
if o.alias
collector << " AS "
visit o.alias, collector
else
collector
end
end
def visit_Arel_Nodes_Extract o
"EXTRACT(#{o.field.to_s.upcase} FROM #{visit o.expr})#{o.alias ? " AS #{visit o.alias}" : ''}"
end
def visit_Arel_Nodes_Count o, collector
aggregate "COUNT", o, collector
end
def visit_Arel_Nodes_Sum o, collector
aggregate "SUM", o, collector
end
def visit_Arel_Nodes_Max o, collector
aggregate "MAX", o, collector
end
def visit_Arel_Nodes_Min o, collector
aggregate "MIN", o, collector
end
def visit_Arel_Nodes_Avg o, collector
aggregate "AVG", o, collector
end
def visit_Arel_Nodes_TableAlias o, collector
collector = visit o.relation, collector
collector << " "
collector << quote_table_name(o.name)
end
def visit_Arel_Nodes_Between o, collector
collector = visit o.left, collector
collector << " BETWEEN "
visit o.right, collector
end
def visit_Arel_Nodes_GreaterThanOrEqual o, collector
collector = visit o.left, collector
collector << " >= "
visit o.right, collector
end
def visit_Arel_Nodes_GreaterThan o, collector
collector = visit o.left, collector
collector << " > "
visit o.right, collector
end
def visit_Arel_Nodes_LessThanOrEqual o, collector
collector = visit o.left, collector
collector << " <= "
visit o.right, collector
end
def visit_Arel_Nodes_LessThan o, collector
collector = visit o.left, collector
collector << " < "
visit o.right, collector
end
def visit_Arel_Nodes_Matches o, collector
collector = visit o.left, collector
collector << " LIKE "
visit o.right, collector
end
def visit_Arel_Nodes_DoesNotMatch o, collector
collector = visit o.left, collector
collector << " NOT LIKE "
visit o.right, collector
end
def visit_Arel_Nodes_JoinSource o, collector
if o.left
collector = visit o.left, collector
end
if o.right.any?
collector << " " if o.left
collector = inject_join o.right, collector, ' '
end
collector
end
def visit_Arel_Nodes_Regexp o, collector
raise NotImplementedError, '~ not implemented for this db'
end
def visit_Arel_Nodes_NotRegexp o, collector
raise NotImplementedError, '!~ not implemented for this db'
end
def visit_Arel_Nodes_StringJoin o, collector
visit o.left, collector
end
def visit_Arel_Nodes_FullOuterJoin o
"FULL OUTER JOIN #{visit o.left} #{visit o.right}"
end
def visit_Arel_Nodes_OuterJoin o, collector
collector << "LEFT OUTER JOIN "
collector = visit o.left, collector
collector << " "
visit o.right, collector
end
def visit_Arel_Nodes_RightOuterJoin o
"RIGHT OUTER JOIN #{visit o.left} #{visit o.right}"
end
def visit_Arel_Nodes_InnerJoin o, collector
collector << "INNER JOIN "
collector = visit o.left, collector
if o.right
collector << SPACE
visit(o.right, collector)
else
collector
end
end
def visit_Arel_Nodes_On o, collector
collector << "ON "
visit o.expr, collector
end
def visit_Arel_Nodes_Not o, collector
collector << "NOT ("
visit(o.expr, collector) << ")"
end
def visit_Arel_Table o, collector
if o.table_alias
collector << "#{quote_table_name o.name} #{quote_table_name o.table_alias}"
else
collector << quote_table_name(o.name)
end
end
def visit_Arel_Nodes_In o, collector
if Array === o.right && o.right.empty?
collector << '1=0'
else
collector = visit o.left, collector
collector << " IN ("
visit(o.right, collector) << ")"
end
end
def visit_Arel_Nodes_NotIn o, collector
if Array === o.right && o.right.empty?
collector << '1=1'
else
collector = visit o.left, collector
collector << " NOT IN ("
collector = visit o.right, collector
collector << ")"
end
end
def visit_Arel_Nodes_And o, collector
inject_join o.children, collector, " AND "
end
def visit_Arel_Nodes_Or o, collector
collector = visit o.left, collector
collector << " OR "
visit o.right, collector
end
def visit_Arel_Nodes_Assignment o, collector
case o.right
when Arel::Nodes::UnqualifiedColumn, Arel::Attributes::Attribute
collector = visit o.left, collector
collector << " = "
visit o.right, collector
else
collector = visit o.left, collector
collector << " = "
collector << quote(o.right, column_for(o.left)).to_s
end
end
def visit_Arel_Nodes_Equality o, collector
right = o.right
collector = visit o.left, collector
if right.nil?
collector << " IS NULL"
else
collector << " = "
visit right, collector
end
end
def visit_Arel_Nodes_NotEqual o, collector
right = o.right
collector = visit o.left, collector
if right.nil?
collector << " IS NOT NULL"
else
collector << " != "
visit right, collector
end
end
def visit_Arel_Nodes_As o, collector
collector = visit o.left, collector
collector << " AS "
visit o.right, collector
end
def visit_Arel_Nodes_UnqualifiedColumn o, collector
collector << "#{quote_column_name o.name}"
collector
end
def visit_Arel_Attributes_Attribute o, collector
join_name = o.relation.table_alias || o.relation.name
collector << "#{quote_table_name join_name}.#{quote_column_name o.name}"
end
alias :visit_Arel_Attributes_Integer :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_Float :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_Decimal :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_String :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_Time :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_Boolean :visit_Arel_Attributes_Attribute
def literal o, collector; collector << o.to_s; end
alias :visit_Arel_Nodes_BindParam :literal
alias :visit_Arel_Nodes_SqlLiteral :literal
alias :visit_Bignum :literal
alias :visit_Fixnum :literal
def quoted o, a
quote(o, column_for(a))
end
def unsupported o
raise "unsupported: #{o.class.name}"
end
alias :visit_ActiveSupport_Multibyte_Chars :unsupported
alias :visit_ActiveSupport_StringInquirer :unsupported
alias :visit_BigDecimal :unsupported
alias :visit_Class :unsupported
alias :visit_Date :unsupported
alias :visit_DateTime :unsupported
alias :visit_FalseClass :unsupported
alias :visit_Float :unsupported
alias :visit_Hash :unsupported
alias :visit_NilClass :unsupported
alias :visit_String :unsupported
alias :visit_Symbol :unsupported
alias :visit_Time :unsupported
alias :visit_TrueClass :unsupported
def visit_Arel_Nodes_InfixOperation o, collector
collector = visit o.left, collector
collector << " #{o.operator} "
visit o.right, collector
end
alias :visit_Arel_Nodes_Addition :visit_Arel_Nodes_InfixOperation
alias :visit_Arel_Nodes_Subtraction :visit_Arel_Nodes_InfixOperation
alias :visit_Arel_Nodes_Multiplication :visit_Arel_Nodes_InfixOperation
alias :visit_Arel_Nodes_Division :visit_Arel_Nodes_InfixOperation
def visit_Array o, collector
inject_join o, collector, ", "
end
def quote value, column = nil
return value if Arel::Nodes::SqlLiteral === value
@connection.quote value, column
end
def quote_table_name name
return name if Arel::Nodes::SqlLiteral === name
@quoted_tables[name] ||= @connection.quote_table_name(name)
end
def quote_column_name name
@quoted_columns[name] ||= Arel::Nodes::SqlLiteral === name ? name : @connection.quote_column_name(name)
end
def maybe_visit thing, collector
return collector unless thing
collector << " "
visit thing, collector
end
def inject_join list, collector, join_str
len = list.length - 1
list.each_with_index.inject(collector) { |c, (x,i)|
if i == len
visit x, c
else
visit(x, c) << join_str
end
}
end
def infix_value o, collector, value
collector = visit o.left, collector
collector << value
visit o.right, collector
end
def aggregate name, o, collector
collector << "#{name}("
if o.distinct
collector << "DISTINCT "
end
collector = inject_join(o.expressions, collector, ", ") << ")"
if o.alias
collector << " AS "
visit o.alias, collector
else
collector
end
end
end
end
end
|