/usr/lib/ruby/vendor_ruby/sequel/dataset/actions.rb is in ruby-sequel 4.1.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 | module Sequel
class Dataset
# ---------------------
# :section: 2 - Methods that execute code on the database
# These methods all execute the dataset's SQL on the database.
# They don't return modified datasets, so if used in a method chain
# they should be the last method called.
# ---------------------
# Action methods defined by Sequel that execute code on the database.
ACTION_METHODS = (<<-METHS).split.map{|x| x.to_sym}
<< [] []= all avg count columns columns! delete each
empty? fetch_rows first first! get import insert insert_multiple interval last
map max min multi_insert paged_each range select_hash select_hash_groups select_map select_order_map
set single_record single_value sum to_csv to_hash to_hash_groups truncate update
METHS
# REMOVE40 []= insert_multiple set to_csv
# Inserts the given argument into the database. Returns self so it
# can be used safely when chaining:
#
# DB[:items] << {:id=>0, :name=>'Zero'} << DB[:old_items].select(:id, name)
def <<(arg)
insert(arg)
self
end
# Returns the first record matching the conditions. Examples:
#
# DB[:table][:id=>1] # SELECT * FROM table WHERE (id = 1) LIMIT 1
# # => {:id=1}
def [](*conditions)
raise(Error, ARRAY_ACCESS_ERROR_MSG) if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0
first(*conditions)
end
# Returns an array with all records in the dataset. If a block is given,
# the array is iterated over after all items have been loaded.
#
# DB[:table].all # SELECT * FROM table
# # => [{:id=>1, ...}, {:id=>2, ...}, ...]
#
# # Iterate over all rows in the table
# DB[:table].all{|row| p row}
def all(&block)
a = []
each{|r| a << r}
post_load(a)
a.each(&block) if block
a
end
# Returns the average value for the given column/expression.
# Uses a virtual row block if no argument is given.
#
# DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1
# # => 3
# DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1
# # => 1
def avg(column=Sequel.virtual_row(&Proc.new))
aggregate_dataset.get{avg(column).as(:avg)}
end
# Returns the columns in the result set in order as an array of symbols.
# If the columns are currently cached, returns the cached value. Otherwise,
# a SELECT query is performed to retrieve a single row in order to get the columns.
#
# If you are looking for all columns for a single table and maybe some information about
# each column (e.g. database type), see <tt>Database#schema</tt>.
#
# DB[:table].columns
# # => [:id, :name]
def columns
return @columns if @columns
ds = unfiltered.unordered.naked.clone(:distinct => nil, :limit => 1, :offset=>nil)
ds.each{break}
@columns = ds.instance_variable_get(:@columns)
@columns || []
end
# Ignore any cached column information and perform a query to retrieve
# a row in order to get the columns.
#
# DB[:table].columns!
# # => [:id, :name]
def columns!
@columns = nil
columns
end
# Returns the number of records in the dataset. If an argument is provided,
# it is used as the argument to count. If a block is provided, it is
# treated as a virtual row, and the result is used as the argument to
# count.
#
# DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1
# # => 3
# DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1
# # => 2
# DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1
# # => 1
def count(arg=(no_arg=true), &block)
if no_arg
if block
arg = Sequel.virtual_row(&block)
aggregate_dataset.get{count(arg).as(count)}
else
aggregate_dataset.get{count(:*){}.as(count)}.to_i
end
elsif block
raise Error, 'cannot provide both argument and block to Dataset#count'
else
aggregate_dataset.get{count(arg).as(count)}
end
end
# Deletes the records in the dataset. The returned value should be
# number of records deleted, but that is adapter dependent.
#
# DB[:table].delete # DELETE * FROM table
# # => 3
def delete(&block)
sql = delete_sql
if uses_returning?(:delete)
returning_fetch_rows(sql, &block)
else
execute_dui(sql)
end
end
# Iterates over the records in the dataset as they are yielded from the
# database adapter, and returns self.
#
# DB[:table].each{|row| p row} # SELECT * FROM table
#
# Note that this method is not safe to use on many adapters if you are
# running additional queries inside the provided block. If you are
# running queries inside the block, you should use +all+ instead of +each+
# for the outer queries, or use a separate thread or shard inside +each+.
def each
if row_proc = @row_proc
fetch_rows(select_sql){|r| yield row_proc.call(r)}
else
fetch_rows(select_sql){|r| yield r}
end
self
end
# Returns true if no records exist in the dataset, false otherwise
#
# DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1
# # => false
def empty?
get(Sequel::SQL::AliasedExpression.new(1, :one)).nil?
end
# If a integer argument is given, it is interpreted as a limit, and then returns all
# matching records up to that limit. If no argument is passed,
# it returns the first matching record. If any other type of
# argument(s) is passed, it is given to filter and the
# first matching record is returned. If a block is given, it is used
# to filter the dataset before returning anything.
#
# If there are no records in the dataset, returns nil (or an empty
# array if an integer argument is given).
#
# Examples:
#
# DB[:table].first # SELECT * FROM table LIMIT 1
# # => {:id=>7}
#
# DB[:table].first(2) # SELECT * FROM table LIMIT 2
# # => [{:id=>6}, {:id=>4}]
#
# DB[:table].first(:id=>2) # SELECT * FROM table WHERE (id = 2) LIMIT 1
# # => {:id=>2}
#
# DB[:table].first("id = 3") # SELECT * FROM table WHERE (id = 3) LIMIT 1
# # => {:id=>3}
#
# DB[:table].first("id = ?", 4) # SELECT * FROM table WHERE (id = 4) LIMIT 1
# # => {:id=>4}
#
# DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1
# # => {:id=>5}
#
# DB[:table].first("id > ?", 4){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1
# # => {:id=>5}
#
# DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2
# # => [{:id=>1}]
def first(*args, &block)
ds = block ? filter(&block) : self
if args.empty?
ds.single_record
else
args = (args.size == 1) ? args.first : args
if args.is_a?(Integer)
ds.limit(args).all
else
ds.filter(args).single_record
end
end
end
# Calls first. If first returns nil (signaling that no
# row matches), raise a Sequel::NoMatchingRow exception.
def first!(*args, &block)
first(*args, &block) || raise(Sequel::NoMatchingRow)
end
# Return the column value for the first matching record in the dataset.
# Raises an error if both an argument and block is given.
#
# DB[:table].get(:id) # SELECT id FROM table LIMIT 1
# # => 3
#
# ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1
# # => 6
#
# You can pass an array of arguments to return multiple arguments,
# but you must make sure each element in the array has an alias that
# Sequel can determine:
#
# DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1
# # => [3, 'foo']
#
# DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1
# # => [6, 'foo']
def get(column=(no_arg=true; nil), &block)
ds = naked
if block
raise(Error, ARG_BLOCK_ERROR_MSG) unless no_arg
ds = ds.select(&block)
column = ds.opts[:select]
column = nil if column.is_a?(Array) && column.length < 2
else
ds = if column.is_a?(Array)
ds.select(*column)
else
ds.select(auto_alias_expression(column))
end
end
if column.is_a?(Array)
if r = ds.single_record
r.values_at(*hash_key_symbols(column))
end
else
ds.single_value
end
end
# Inserts multiple records into the associated table. This method can be
# used to efficiently insert a large number of records into a table in a
# single query if the database supports it. Inserts
# are automatically wrapped in a transaction.
#
# This method is called with a columns array and an array of value arrays:
#
# DB[:table].import([:x, :y], [[1, 2], [3, 4]])
# # INSERT INTO table (x, y) VALUES (1, 2)
# # INSERT INTO table (x, y) VALUES (3, 4)
#
# This method also accepts a dataset instead of an array of value arrays:
#
# DB[:table].import([:x, :y], DB[:table2].select(:a, :b))
# # INSERT INTO table (x, y) SELECT a, b FROM table2
#
# Options:
# :commit_every :: Open a new transaction for every given number of records.
# For example, if you provide a value of 50, will commit
# after every 50 records.
# :server :: Set the server/shard to use for the transaction and insert
# queries.
# :slice :: Same as :commit_every, :commit_every takes precedence.
def import(columns, values, opts=OPTS)
return @db.transaction{insert(columns, values)} if values.is_a?(Dataset)
return if values.empty?
raise(Error, IMPORT_ERROR_MSG) if columns.empty?
ds = opts[:server] ? server(opts[:server]) : self
if slice_size = opts[:commit_every] || opts[:slice]
offset = 0
rows = []
while offset < values.length
rows << ds._import(columns, values[offset, slice_size], opts)
offset += slice_size
end
rows.flatten
else
ds._import(columns, values, opts)
end
end
# Inserts values into the associated table. The returned value is generally
# the value of the primary key for the inserted row, but that is adapter dependent.
#
# +insert+ handles a number of different argument formats:
# no arguments or single empty hash :: Uses DEFAULT VALUES
# single hash :: Most common format, treats keys as columns an values as values
# single array :: Treats entries as values, with no columns
# two arrays :: Treats first array as columns, second array as values
# single Dataset :: Treats as an insert based on a selection from the dataset given,
# with no columns
# array and dataset :: Treats as an insert based on a selection from the dataset
# given, with the columns given by the array.
#
# Examples:
#
# DB[:items].insert
# # INSERT INTO items DEFAULT VALUES
#
# DB[:items].insert({})
# # INSERT INTO items DEFAULT VALUES
#
# DB[:items].insert([1,2,3])
# # INSERT INTO items VALUES (1, 2, 3)
#
# DB[:items].insert([:a, :b], [1,2])
# # INSERT INTO items (a, b) VALUES (1, 2)
#
# DB[:items].insert(:a => 1, :b => 2)
# # INSERT INTO items (a, b) VALUES (1, 2)
#
# DB[:items].insert(DB[:old_items])
# # INSERT INTO items SELECT * FROM old_items
#
# DB[:items].insert([:a, :b], DB[:old_items])
# # INSERT INTO items (a, b) SELECT * FROM old_items
def insert(*values, &block)
sql = insert_sql(*values)
if uses_returning?(:insert)
returning_fetch_rows(sql, &block)
else
execute_insert(sql)
end
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=Sequel.virtual_row(&Proc.new))
aggregate_dataset.get{(max(column) - min(column)).as(:interval)}
end
# Reverses the order and then runs #first with the given arguments and block. Note that this
# will not necessarily give you the last record in the dataset,
# unless you have an unambiguous order. If there is not
# currently an order for this dataset, raises an +Error+.
#
# DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1
# # => {:id=>10}
#
# DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2
# # => [{:id=>1}, {:id=>2}]
def last(*args, &block)
raise(Error, 'No order specified') unless @opts[:order]
reverse.first(*args, &block)
end
# Maps column values for each record in the dataset (if a column name is
# given), or performs the stock mapping functionality of +Enumerable+ otherwise.
# Raises an +Error+ if both an argument and block are given.
#
# DB[:table].map(:id) # SELECT * FROM table
# # => [1, 2, 3, ...]
#
# DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table
# # => [2, 4, 6, ...]
#
# You can also provide an array of column names:
#
# DB[:table].map([:id, :name]) # SELECT * FROM table
# # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
def map(column=nil, &block)
if column
raise(Error, ARG_BLOCK_ERROR_MSG) if block
return naked.map(column) if row_proc
if column.is_a?(Array)
super(){|r| r.values_at(*column)}
else
super(){|r| r[column]}
end
else
super(&block)
end
end
# Returns the maximum value for the given column/expression.
# Uses a virtual row block if no argument is given.
#
# DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1
# # => 10
# DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1
# # => 7
def max(column=Sequel.virtual_row(&Proc.new))
aggregate_dataset.get{max(column).as(:max)}
end
# Returns the minimum value for the given column/expression.
# Uses a virtual row block if no argument is given.
#
# DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1
# # => 1
# DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1
# # => 0
def min(column=Sequel.virtual_row(&Proc.new))
aggregate_dataset.get{min(column).as(:min)}
end
# This is a front end for import that allows you to submit an array of
# hashes instead of arrays of columns and values:
#
# DB[:table].multi_insert([{:x => 1}, {:x => 2}])
# # INSERT INTO table (x) VALUES (1)
# # INSERT INTO table (x) VALUES (2)
#
# Be aware that all hashes should have the same keys if you use this calling method,
# otherwise some columns could be missed or set to null instead of to default
# values.
#
# This respects the same options as #import.
def multi_insert(hashes, opts=OPTS)
return if hashes.empty?
columns = hashes.first.keys
import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts)
end
# Yields each row in the dataset, but interally uses multiple queries as needed with
# limit and offset to process the entire result set without keeping all
# rows in the dataset in memory, even if the underlying driver buffers all
# query results in memory.
#
# Because this uses multiple queries internally, in order to remain consistent,
# it also uses a transaction internally. Additionally, to make sure that all rows
# in the dataset are yielded and none are yielded twice, the dataset must have an
# unambiguous order. Sequel requires that datasets using this method have an
# order, but it cannot ensure that the order is unambiguous.
#
# Options:
# :rows_per_fetch :: The number of rows to fetch per query. Defaults to 1000.
def paged_each(opts=OPTS)
unless @opts[:order]
raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered"
end
total_limit = @opts[:limit]
offset = @opts[:offset] || 0
if server = @opts[:server]
opts = opts.merge(:server=>server)
end
rows_per_fetch = opts[:rows_per_fetch] || 1000
num_rows_yielded = rows_per_fetch
total_rows = 0
db.transaction(opts) do
while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit)
if total_limit && total_rows + rows_per_fetch > total_limit
rows_per_fetch = total_limit - total_rows
end
num_rows_yielded = 0
limit(rows_per_fetch, offset).each do |row|
num_rows_yielded += 1
total_rows += 1 if total_limit
yield row
end
offset += rows_per_fetch
end
end
self
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=Sequel.virtual_row(&Proc.new))
if r = aggregate_dataset.select{[min(column).as(v1), max(column).as(v2)]}.first
(r[:v1]..r[:v2])
end
end
# Returns a hash with key_column values as keys and value_column values as
# values. Similar to to_hash, but only selects the columns given.
#
# DB[:table].select_hash(:id, :name) # SELECT id, name FROM table
# # => {1=>'a', 2=>'b', ...}
#
# You can also provide an array of column names for either the key_column,
# the value column, or both:
#
# DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table
# # {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}
#
# When using this method, you must be sure that each expression has an alias
# that Sequel can determine. Usually you can do this by calling the #as method
# on the expression and providing an alias.
def select_hash(key_column, value_column)
_select_hash(:to_hash, key_column, value_column)
end
# Returns a hash with key_column values as keys and an array of value_column values.
# Similar to to_hash_groups, but only selects the columns given.
#
# DB[:table].select_hash(:name, :id) # SELECT id, name FROM table
# # => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}
#
# You can also provide an array of column names for either the key_column,
# the value column, or both:
#
# DB[:table].select_hash([:first, :middle], [:last, :id]) # SELECT * FROM table
# # {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}
#
# When using this method, you must be sure that each expression has an alias
# that Sequel can determine. Usually you can do this by calling the #as method
# on the expression and providing an alias.
def select_hash_groups(key_column, value_column)
_select_hash(:to_hash_groups, key_column, value_column)
end
# Selects the column given (either as an argument or as a block), and
# returns an array of all values of that column in the dataset. If you
# give a block argument that returns an array with multiple entries,
# the contents of the resulting array are undefined. Raises an Error
# if called with both an argument and a block.
#
# DB[:table].select_map(:id) # SELECT id FROM table
# # => [3, 5, 8, 1, ...]
#
# DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table
# # => [6, 10, 16, 2, ...]
#
# You can also provide an array of column names:
#
# DB[:table].select_map([:id, :name]) # SELECT id, name FROM table
# # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
#
# If you provide an array of expressions, you must be sure that each entry
# in the array has an alias that Sequel can determine. Usually you can do this
# by calling the #as method on the expression and providing an alias.
def select_map(column=nil, &block)
_select_map(column, false, &block)
end
# The same as select_map, but in addition orders the array by the column.
#
# DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id
# # => [1, 2, 3, 4, ...]
#
# DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2)
# # => [2, 4, 6, 8, ...]
#
# You can also provide an array of column names:
#
# DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name
# # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
#
# If you provide an array of expressions, you must be sure that each entry
# in the array has an alias that Sequel can determine. Usually you can do this
# by calling the #as method on the expression and providing an alias.
def select_order_map(column=nil, &block)
_select_map(column, true, &block)
end
# Returns the first record in the dataset, or nil if the dataset
# has no records. Users should probably use +first+ instead of
# this method.
def single_record
clone(:limit=>1).each{|r| return r}
nil
end
# Returns the first value of the first record in the dataset.
# Returns nil if dataset is empty. Users should generally use
# +get+ instead of this method.
def single_value
if r = ungraphed.naked.single_record
r.values.first
end
end
# Returns the sum for the given column/expression.
# Uses a virtual row block if no column is given.
#
# DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1
# # => 55
# DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1
# # => 10
def sum(column=Sequel.virtual_row(&Proc.new))
aggregate_dataset.get{sum(column).as(:sum)}
end
# Returns a hash with one column used as key and another used as value.
# If rows have duplicate values for the key column, the latter row(s)
# will overwrite the value of the previous row(s). If the value_column
# is not given or nil, uses the entire hash as the value.
#
# DB[:table].to_hash(:id, :name) # SELECT * FROM table
# # {1=>'Jim', 2=>'Bob', ...}
#
# DB[:table].to_hash(:id) # SELECT * FROM table
# # {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}
#
# You can also provide an array of column names for either the key_column,
# the value column, or both:
#
# DB[:table].to_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table
# # {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...}
#
# DB[:table].to_hash([:id, :name]) # SELECT * FROM table
# # {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob'=>{:id=>2, :name=>'Bob'}, ...}
def to_hash(key_column, value_column = nil)
h = {}
if value_column
return naked.to_hash(key_column, value_column) if row_proc
if value_column.is_a?(Array)
if key_column.is_a?(Array)
each{|r| h[r.values_at(*key_column)] = r.values_at(*value_column)}
else
each{|r| h[r[key_column]] = r.values_at(*value_column)}
end
else
if key_column.is_a?(Array)
each{|r| h[r.values_at(*key_column)] = r[value_column]}
else
each{|r| h[r[key_column]] = r[value_column]}
end
end
elsif key_column.is_a?(Array)
each{|r| h[r.values_at(*key_column)] = r}
else
each{|r| h[r[key_column]] = r}
end
h
end
# Returns a hash with one column used as key and the values being an
# array of column values. If the value_column is not given or nil, uses
# the entire hash as the value.
#
# DB[:table].to_hash(:name, :id) # SELECT * FROM table
# # {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...}
#
# DB[:table].to_hash(:name) # SELECT * FROM table
# # {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}
#
# You can also provide an array of column names for either the key_column,
# the value column, or both:
#
# DB[:table].to_hash([:first, :middle], [:last, :id]) # SELECT * FROM table
# # {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...}
#
# DB[:table].to_hash([:first, :middle]) # SELECT * FROM table
# # {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}
def to_hash_groups(key_column, value_column = nil)
h = {}
if value_column
return naked.to_hash_groups(key_column, value_column) if row_proc
if value_column.is_a?(Array)
if key_column.is_a?(Array)
each{|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)}
else
each{|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)}
end
else
if key_column.is_a?(Array)
each{|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]}
else
each{|r| (h[r[key_column]] ||= []) << r[value_column]}
end
end
elsif key_column.is_a?(Array)
each{|r| (h[r.values_at(*key_column)] ||= []) << r}
else
each{|r| (h[r[key_column]] ||= []) << r}
end
h
end
# Truncates the dataset. Returns nil.
#
# DB[:table].truncate # TRUNCATE table
# # => nil
def truncate
execute_ddl(truncate_sql)
end
# Updates values for the dataset. The returned value is generally the
# number of rows updated, but that is adapter dependent. +values+ should
# a hash where the keys are columns to set and values are the values to
# which to set the columns.
#
# DB[:table].update(:x=>nil) # UPDATE table SET x = NULL
# # => 10
#
# DB[:table].update(:x=>:x+1, :y=>0) # UPDATE table SET x = (x + 1), y = 0
# # => 10
def update(values=OPTS, &block)
sql = update_sql(values)
if uses_returning?(:update)
returning_fetch_rows(sql, &block)
else
execute_dui(sql)
end
end
# Execute the given SQL and return the number of rows deleted. This exists
# solely as an optimization, replacing with_sql(sql).delete. It's significantly
# faster as it does not require cloning the current dataset.
def with_sql_delete(sql)
execute_dui(sql)
end
protected
# Internals of #import. If primary key values are requested, use
# separate insert commands for each row. Otherwise, call #multi_insert_sql
# and execute each statement it gives separately.
def _import(columns, values, opts)
trans_opts = opts.merge(:server=>@opts[:server])
if opts[:return] == :primary_key
@db.transaction(trans_opts){values.map{|v| insert(columns, v)}}
else
stmts = multi_insert_sql(columns, values)
@db.transaction(trans_opts){stmts.each{|st| execute_dui(st)}}
end
end
# Return an array of arrays of values given by the symbols in ret_cols.
def _select_map_multiple(ret_cols)
map{|r| r.values_at(*ret_cols)}
end
# Returns an array of the first value in each row.
def _select_map_single
map{|r| r.values.first}
end
private
# Internals of +select_hash+ and +select_hash_groups+
def _select_hash(meth, key_column, value_column)
select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])).
send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column))
end
# Internals of +select_map+ and +select_order_map+
def _select_map(column, order, &block)
ds = ungraphed.naked
columns = Array(column)
virtual_row_columns(columns, block)
select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns
ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order
if column.is_a?(Array) || (columns.length > 1)
ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols))
else
ds.select(auto_alias_expression(select_cols.first))._select_map_single
end
end
# Automatically alias the given expression if it does not have an identifiable alias.
def auto_alias_expression(v)
case v
when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression
v
else
SQL::AliasedExpression.new(v, :v)
end
end
# Set the server to use to :default unless it is already set in the passed opts
def default_server_opts(opts)
{:server=>@opts[:server] || :default}.merge(opts)
end
# Execute the given select SQL on the database using execute. Use the
# :read_only server unless a specific server is set.
def execute(sql, opts=OPTS, &block)
@db.execute(sql, {:server=>@opts[:server] || :read_only}.merge(opts), &block)
end
# Execute the given SQL on the database using execute_ddl.
def execute_ddl(sql, opts=OPTS, &block)
@db.execute_ddl(sql, default_server_opts(opts), &block)
nil
end
# Execute the given SQL on the database using execute_dui.
def execute_dui(sql, opts=OPTS, &block)
@db.execute_dui(sql, default_server_opts(opts), &block)
end
# Execute the given SQL on the database using execute_insert.
def execute_insert(sql, opts=OPTS, &block)
@db.execute_insert(sql, default_server_opts(opts), &block)
end
# Return a plain symbol given a potentially qualified or aliased symbol,
# specifying the symbol that is likely to be used as the hash key
# for the column when records are returned. Return nil if no hash key
# can be determined
def _hash_key_symbol(s, recursing=false)
case s
when Symbol
_, c, a = split_symbol(s)
(a || c).to_sym
when SQL::Identifier, SQL::Wrapper
_hash_key_symbol(s.value, true)
when SQL::QualifiedIdentifier
_hash_key_symbol(s.column, true)
when SQL::AliasedExpression
_hash_key_symbol(s.aliaz, true)
when String
s.to_sym if recursing
end
end
# Return a plain symbol given a potentially qualified or aliased symbol,
# specifying the symbol that is likely to be used as the hash key
# for the column when records are returned. Raise Error if the hash key
# symbol cannot be returned.
def hash_key_symbol(s)
if v = _hash_key_symbol(s)
v
else
raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression")
end
end
# If s is an array, return an array with the given hash key symbols.
# Otherwise, return a hash key symbol for the given expression
# If a hash key symbol cannot be determined, raise an error.
def hash_key_symbols(s)
s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s)
end
# Modify the identifier returned from the database based on the
# identifier_output_method.
def output_identifier(v)
v = 'untitled' if v == ''
(i = identifier_output_method) ? v.to_s.send(i).to_sym : v.to_sym
end
# This is run inside .all, after all of the records have been loaded
# via .each, but before any block passed to all is called. It is called with
# a single argument, an array of all returned records. Does nothing by
# default, added to make the model eager loading code simpler.
def post_load(all_records)
end
# Called by insert/update/delete when returning is used.
# Yields each row as a plain hash to the block if one is given, or returns
# an array of plain hashes for all rows if a block is not given
def returning_fetch_rows(sql, &block)
if block
default_server.fetch_rows(sql, &block)
nil
else
rows = []
default_server.fetch_rows(sql){|r| rows << r}
rows
end
end
# Return the unaliased part of the identifier. Handles both
# implicit aliases in symbols, as well as SQL::AliasedExpression
# objects. Other objects are returned as is.
def unaliased_identifier(c)
case c
when Symbol
c_table, column, _ = split_symbol(c)
c_table ? SQL::QualifiedIdentifier.new(c_table, column.to_sym) : column.to_sym
when SQL::AliasedExpression
c.expression
when SQL::OrderedExpression
case expr = c.expression
when Symbol, SQL::AliasedExpression
SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls)
else
c
end
else
c
end
end
end
end
|