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
|
require 'active_record/connection_adapters/abstract_adapter'
module ActiveRecord
class Base
# Establishes a connection to the database that's used by all Active Record objects
def self.postgresql_connection(config) # :nodoc:
require_library_or_gem 'postgres' unless self.class.const_defined?(:PGconn)
config = config.symbolize_keys
host = config[:host]
port = config[:port] || 5432
username = config[:username].to_s
password = config[:password].to_s
min_messages = config[:min_messages]
if config.has_key?(:database)
database = config[:database]
else
raise ArgumentError, "No database specified. Missing argument: database."
end
pga = ConnectionAdapters::PostgreSQLAdapter.new(
PGconn.connect(host, port, "", "", database, username, password), logger, config
)
PGconn.translate_results = false if PGconn.respond_to? :translate_results=
pga.schema_search_path = config[:schema_search_path] || config[:schema_order]
pga
end
end
module ConnectionAdapters
# The PostgreSQL adapter works both with the C-based (http://www.postgresql.jp/interfaces/ruby/) and the Ruby-base
# (available both as gem and from http://rubyforge.org/frs/?group_id=234&release_id=1145) drivers.
#
# Options:
#
# * <tt>:host</tt> -- Defaults to localhost
# * <tt>:port</tt> -- Defaults to 5432
# * <tt>:username</tt> -- Defaults to nothing
# * <tt>:password</tt> -- Defaults to nothing
# * <tt>:database</tt> -- The name of the database. No default, must be provided.
# * <tt>:schema_search_path</tt> -- An optional schema search path for the connection given as a string of comma-separated schema names. This is backward-compatible with the :schema_order option.
# * <tt>:encoding</tt> -- An optional client encoding that is using in a SET client_encoding TO <encoding> call on connection.
# * <tt>:min_messages</tt> -- An optional client min messages that is using in a SET client_min_messages TO <min_messages> call on connection.
# * <tt>:allow_concurrency</tt> -- If true, use async query methods so Ruby threads don't deadlock; otherwise, use blocking query methods.
class PostgreSQLAdapter < AbstractAdapter
def adapter_name
'PostgreSQL'
end
def initialize(connection, logger, config = {})
super(connection, logger)
@config = config
@async = config[:allow_concurrency]
configure_connection
end
# Is this connection alive and ready for queries?
def active?
if @connection.respond_to?(:status)
@connection.status == PGconn::CONNECTION_OK
else
@connection.query 'SELECT 1'
true
end
# postgres-pr raises a NoMethodError when querying if no conn is available
rescue PGError, NoMethodError
false
end
# Close then reopen the connection.
def reconnect!
# TODO: postgres-pr doesn't have PGconn#reset.
if @connection.respond_to?(:reset)
@connection.reset
configure_connection
end
end
def disconnect!
# Both postgres and postgres-pr respond to :close
@connection.close rescue nil
end
def native_database_types
{
:primary_key => "serial primary key",
:string => { :name => "character varying", :limit => 255 },
:text => { :name => "text" },
:integer => { :name => "integer" },
:float => { :name => "float" },
:decimal => { :name => "decimal" },
:datetime => { :name => "timestamp" },
:timestamp => { :name => "timestamp" },
:time => { :name => "time" },
:date => { :name => "date" },
:binary => { :name => "bytea" },
:boolean => { :name => "boolean" }
}
end
def supports_migrations?
true
end
def table_alias_length
63
end
# QUOTING ==================================================
def quote(value, column = nil)
if value.kind_of?(String) && column && column.type == :binary
"'#{escape_bytea(value)}'"
else
super
end
end
def quote_column_name(name)
%("#{name}")
end
def quoted_date(value)
value.strftime("%Y-%m-%d %H:%M:%S.#{sprintf("%06d", value.usec)}")
end
# DATABASE STATEMENTS ======================================
def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
execute(sql, name)
table = sql.split(" ", 4)[2]
id_value || last_insert_id(table, sequence_name || default_sequence_name(table, pk))
end
def query(sql, name = nil) #:nodoc:
log(sql, name) do
if @async
@connection.async_query(sql)
else
@connection.query(sql)
end
end
end
def execute(sql, name = nil) #:nodoc:
log(sql, name) do
if @async
@connection.async_exec(sql)
else
@connection.exec(sql)
end
end
end
def update(sql, name = nil) #:nodoc:
execute(sql, name).cmdtuples
end
def begin_db_transaction #:nodoc:
execute "BEGIN"
end
def commit_db_transaction #:nodoc:
execute "COMMIT"
end
def rollback_db_transaction #:nodoc:
execute "ROLLBACK"
end
# SCHEMA STATEMENTS ========================================
# Return the list of all tables in the schema search path.
def tables(name = nil) #:nodoc:
schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
query(<<-SQL, name).map { |row| row[0] }
SELECT tablename
FROM pg_tables
WHERE schemaname IN (#{schemas})
SQL
end
def indexes(table_name, name = nil) #:nodoc:
result = query(<<-SQL, name)
SELECT i.relname, d.indisunique, a.attname
FROM pg_class t, pg_class i, pg_index d, pg_attribute a
WHERE i.relkind = 'i'
AND d.indexrelid = i.oid
AND d.indisprimary = 'f'
AND t.oid = d.indrelid
AND t.relname = '#{table_name}'
AND a.attrelid = t.oid
AND ( d.indkey[0]=a.attnum OR d.indkey[1]=a.attnum
OR d.indkey[2]=a.attnum OR d.indkey[3]=a.attnum
OR d.indkey[4]=a.attnum OR d.indkey[5]=a.attnum
OR d.indkey[6]=a.attnum OR d.indkey[7]=a.attnum
OR d.indkey[8]=a.attnum OR d.indkey[9]=a.attnum )
ORDER BY i.relname
SQL
current_index = nil
indexes = []
result.each do |row|
if current_index != row[0]
indexes << IndexDefinition.new(table_name, row[0], row[1] == "t", [])
current_index = row[0]
end
indexes.last.columns << row[2]
end
indexes
end
def columns(table_name, name = nil) #:nodoc:
column_definitions(table_name).collect do |name, type, default, notnull, typmod|
# typmod now unused as limit, precision, scale all handled by superclass
Column.new(name, default_value(default), translate_field_type(type), notnull == "f")
end
end
# Set the schema search path to a string of comma-separated schema names.
# Names beginning with $ are quoted (e.g. $user => '$user')
# See http://www.postgresql.org/docs/8.0/interactive/ddl-schemas.html
def schema_search_path=(schema_csv) #:nodoc:
if schema_csv
execute "SET search_path TO #{schema_csv}"
@schema_search_path = nil
end
end
def schema_search_path #:nodoc:
@schema_search_path ||= query('SHOW search_path')[0][0]
end
def default_sequence_name(table_name, pk = nil)
default_pk, default_seq = pk_and_sequence_for(table_name)
default_seq || "#{table_name}_#{pk || default_pk || 'id'}_seq"
end
# Resets sequence to the max value of the table's pk if present.
def reset_pk_sequence!(table, pk = nil, sequence = nil)
unless pk and sequence
default_pk, default_sequence = pk_and_sequence_for(table)
pk ||= default_pk
sequence ||= default_sequence
end
if pk
if sequence
select_value <<-end_sql, 'Reset sequence'
SELECT setval('#{sequence}', (SELECT COALESCE(MAX(#{pk})+(SELECT increment_by FROM #{sequence}), (SELECT min_value FROM #{sequence})) FROM #{table}), false)
end_sql
else
@logger.warn "#{table} has primary key #{pk} with no default sequence" if @logger
end
end
end
# Find a table's primary key and sequence.
def pk_and_sequence_for(table)
# First try looking for a sequence with a dependency on the
# given table's primary key.
result = query(<<-end_sql, 'PK and serial sequence')[0]
SELECT attr.attname, name.nspname, seq.relname
FROM pg_class seq,
pg_attribute attr,
pg_depend dep,
pg_namespace name,
pg_constraint cons
WHERE seq.oid = dep.objid
AND seq.relnamespace = name.oid
AND seq.relkind = 'S'
AND attr.attrelid = dep.refobjid
AND attr.attnum = dep.refobjsubid
AND attr.attrelid = cons.conrelid
AND attr.attnum = cons.conkey[1]
AND cons.contype = 'p'
AND dep.refobjid = '#{table}'::regclass
end_sql
if result.nil? or result.empty?
# If that fails, try parsing the primary key's default value.
# Support the 7.x and 8.0 nextval('foo'::text) as well as
# the 8.1+ nextval('foo'::regclass).
# TODO: assumes sequence is in same schema as table.
result = query(<<-end_sql, 'PK and custom sequence')[0]
SELECT attr.attname, name.nspname, split_part(def.adsrc, '''', 2)
FROM pg_class t
JOIN pg_namespace name ON (t.relnamespace = name.oid)
JOIN pg_attribute attr ON (t.oid = attrelid)
JOIN pg_attrdef def ON (adrelid = attrelid AND adnum = attnum)
JOIN pg_constraint cons ON (conrelid = adrelid AND adnum = conkey[1])
WHERE t.oid = '#{table}'::regclass
AND cons.contype = 'p'
AND def.adsrc ~* 'nextval'
end_sql
end
# check for existence of . in sequence name as in public.foo_sequence. if it does not exist, return unqualified sequence
# We cannot qualify unqualified sequences, as rails doesn't qualify any table access, using the search path
[result.first, result.last]
rescue
nil
end
def rename_table(name, new_name)
execute "ALTER TABLE #{name} RENAME TO #{new_name}"
end
def add_column(table_name, column_name, type, options = {})
default = options[:default]
notnull = options[:null] == false
# Add the column.
execute("ALTER TABLE #{table_name} ADD COLUMN #{column_name} #{type_to_sql(type, options[:limit])}")
# Set optional default. If not null, update nulls to the new default.
unless default.nil?
change_column_default(table_name, column_name, default)
if notnull
execute("UPDATE #{table_name} SET #{column_name}='#{default}' WHERE #{column_name} IS NULL")
end
end
if notnull
execute("ALTER TABLE #{table_name} ALTER #{column_name} SET NOT NULL")
end
end
def change_column(table_name, column_name, type, options = {}) #:nodoc:
begin
execute "ALTER TABLE #{table_name} ALTER COLUMN #{column_name} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
rescue ActiveRecord::StatementInvalid
# This is PG7, so we use a more arcane way of doing it.
begin_db_transaction
add_column(table_name, "#{column_name}_ar_tmp", type, options)
execute "UPDATE #{table_name} SET #{column_name}_ar_tmp = CAST(#{column_name} AS #{type_to_sql(type, options[:limit], options[:precision], options[:scale])})"
remove_column(table_name, column_name)
rename_column(table_name, "#{column_name}_ar_tmp", column_name)
commit_db_transaction
end
change_column_default(table_name, column_name, options[:default]) unless options[:default].nil?
end
def change_column_default(table_name, column_name, default) #:nodoc:
execute "ALTER TABLE #{table_name} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT '#{default}'"
end
def rename_column(table_name, column_name, new_column_name) #:nodoc:
execute "ALTER TABLE #{table_name} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
end
def remove_index(table_name, options) #:nodoc:
execute "DROP INDEX #{index_name(table_name, options)}"
end
def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
return super unless type.to_s == 'integer'
if limit.nil? || limit == 4
'integer'
elsif limit < 4
'smallint'
else
'bigint'
end
end
# SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
#
# PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
# requires that the ORDER BY include the distinct column.
#
# distinct("posts.id", "posts.created_at desc")
def distinct(columns, order_by)
return "DISTINCT #{columns}" if order_by.blank?
# construct a clean list of column names from the ORDER BY clause, removing
# any asc/desc modifiers
order_columns = order_by.split(',').collect! { |s| s.split.first }
order_columns.delete_if &:blank?
# add the DISTINCT columns to the start of the ORDER BY clause
order_by.replace "#{columns}, #{order_by}"
# return a DISTINCT ON() clause that's distinct on the columns we want but includes
# all the required columns for the ORDER BY to work properly
sql = "DISTINCT ON (#{columns}) #{columns}, "
sql << order_columns * ', '
end
private
BYTEA_COLUMN_TYPE_OID = 17
NUMERIC_COLUMN_TYPE_OID = 1700
TIMESTAMPOID = 1114
TIMESTAMPTZOID = 1184
def configure_connection
if @config[:encoding]
execute("SET client_encoding TO '#{@config[:encoding]}'")
end
if @config[:min_messages]
execute("SET client_min_messages TO '#{@config[:min_messages]}'")
end
end
def last_insert_id(table, sequence_name)
Integer(select_value("SELECT currval('#{sequence_name}')"))
end
def select(sql, name = nil)
res = execute(sql, name)
results = res.result
rows = []
if results.length > 0
fields = res.fields
results.each do |row|
hashed_row = {}
row.each_index do |cel_index|
column = row[cel_index]
case res.type(cel_index)
when BYTEA_COLUMN_TYPE_OID
column = unescape_bytea(column)
when TIMESTAMPTZOID, TIMESTAMPOID
column = cast_to_time(column)
when NUMERIC_COLUMN_TYPE_OID
column = column.to_d if column.respond_to?(:to_d)
end
hashed_row[fields[cel_index]] = column
end
rows << hashed_row
end
end
res.clear
return rows
end
def escape_bytea(s)
if PGconn.respond_to? :escape_bytea
self.class.send(:define_method, :escape_bytea) do |s|
PGconn.escape_bytea(s) if s
end
else
self.class.send(:define_method, :escape_bytea) do |s|
if s
result = ''
s.each_byte { |c| result << sprintf('\\\\%03o', c) }
result
end
end
end
escape_bytea(s)
end
def unescape_bytea(s)
if PGconn.respond_to? :unescape_bytea
self.class.send(:define_method, :unescape_bytea) do |s|
PGconn.unescape_bytea(s) if s
end
else
self.class.send(:define_method, :unescape_bytea) do |s|
if s
result = ''
i, max = 0, s.size
while i < max
char = s[i]
if char == ?\\
if s[i+1] == ?\\
char = ?\\
i += 1
else
char = s[i+1..i+3].oct
i += 3
end
end
result << char
i += 1
end
result
end
end
end
unescape_bytea(s)
end
# Query a table's column names, default values, and types.
#
# The underlying query is roughly:
# SELECT column.name, column.type, default.value
# FROM column LEFT JOIN default
# ON column.table_id = default.table_id
# AND column.num = default.column_num
# WHERE column.table_id = get_table_id('table_name')
# AND column.num > 0
# AND NOT column.is_dropped
# ORDER BY column.num
#
# If the table name is not prefixed with a schema, the database will
# take the first match from the schema search path.
#
# Query implementation notes:
# - format_type includes the column size constraint, e.g. varchar(50)
# - ::regclass is a function that gives the id for a table name
def column_definitions(table_name)
query <<-end_sql
SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
FROM pg_attribute a LEFT JOIN pg_attrdef d
ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attrelid = '#{table_name}'::regclass
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
end_sql
end
# Translate PostgreSQL-specific types into simplified SQL types.
# These are special cases; standard types are handled by
# ConnectionAdapters::Column#simplified_type.
def translate_field_type(field_type)
# Match the beginning of field_type since it may have a size constraint on the end.
case field_type
# PostgreSQL array data types.
when /\[\]$/i then 'string'
when /^timestamp/i then 'datetime'
when /^real|^money/i then 'float'
when /^interval/i then 'string'
# geometric types (the line type is currently not implemented in postgresql)
when /^(?:point|lseg|box|"?path"?|polygon|circle)/i then 'string'
when /^bytea/i then 'binary'
else field_type # Pass through standard types.
end
end
def default_value(value)
# Boolean types
return "t" if value =~ /true/i
return "f" if value =~ /false/i
# Char/String/Bytea type values
return $1 if value =~ /^'(.*)'::(bpchar|text|character varying|bytea)$/
# Numeric values
return value if value =~ /^-?[0-9]+(\.[0-9]*)?/
# Fixed dates / times
return $1 if value =~ /^'(.+)'::(date|timestamp)/
# Anything else is blank, some user type, or some function
# and we can't know the value of that, so return nil.
return nil
end
# Only needed for DateTime instances
def cast_to_time(value)
return value unless value.class == DateTime
v = value
time_array = [v.year, v.month, v.day, v.hour, v.min, v.sec, v.usec]
Time.send(Base.default_timezone, *time_array) rescue nil
end
end
end
end
|