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view libraries/mondelefant/mondelefant.lua @ 406:36f0d1d5ed7d
Further fixes in mondelefant.connect{...} (including proper handling of garbage collection in case of memory allocation errors); Code cleanup (use luaL_setmetatable, which is available since Lua 5.2)
| author | jbe |
|---|---|
| date | Wed Jan 06 18:59:58 2016 +0100 (2016-01-06) |
| parents | 4bcedf32b089 |
| children | c343ce9092ee |
line source
1 #!/usr/bin/env lua
4 ---------------------------
5 -- module initialization --
6 ---------------------------
8 local _G = _G
9 local _VERSION = _VERSION
10 local assert = assert
11 local error = error
12 local getmetatable = getmetatable
13 local ipairs = ipairs
14 local next = next
15 local pairs = pairs
16 local print = print
17 local rawequal = rawequal
18 local rawget = rawget
19 local rawlen = rawlen
20 local rawset = rawset
21 local select = select
22 local setmetatable = setmetatable
23 local tonumber = tonumber
24 local tostring = tostring
25 local type = type
27 local math = math
28 local string = string
29 local table = table
31 local add = table.insert
33 local _M = require("mondelefant_native")
34 if _ENV then
35 _ENV = _M
36 else
37 _G[...] = _M
38 setfenv(1, _M)
39 end
43 ---------------
44 -- selectors --
45 ---------------
47 selector_metatable = {}
48 selector_prototype = {}
49 selector_metatable.__index = selector_prototype
51 local function init_selector(self, db_conn)
52 self._db_conn = db_conn
53 self._mode = "list"
54 self._with = { sep = ", " }
55 self._fields = { sep = ", " }
56 self._distinct = false
57 self._distinct_on = {sep = ", ", expression}
58 self._from = { sep = " " }
59 self._where = { sep = ") AND (" }
60 self._group_by = { sep = ", " }
61 self._having = { sep = ") AND (" }
62 self._combine = { sep = " " }
63 self._order_by = { sep = ", " }
64 self._limit = nil
65 self._offset = nil
66 self._read_lock = { sep = ", " }
67 self._write_lock = { sep = ", " }
68 self._class = nil
69 self._attach = nil
70 return self
71 end
73 --[[--
74 selector = -- new selector
75 <db_handle>:new_selector()
77 Creates a new selector to operate on the given database handle.
78 --]]--
79 function connection_prototype:new_selector()
80 return init_selector(setmetatable({}, selector_metatable), self)
81 end
82 --//--
84 --[[--
85 db_handle = -- handle of database connection
86 <db_selector>:get_db_conn()
88 Returns the database connection handle used by a selector.
90 --]]--
91 function selector_prototype:get_db_conn()
92 return self._db_conn
93 end
94 --//--
96 -- TODO: selector clone?
98 --[[--
99 db_selector = -- same selector returned
100 <db_selector>:single_object_mode()
102 Sets selector to single object mode (mode "object" passed to "query" method of database handle). The selector is modified and returned.
104 --]]--
105 function selector_prototype:single_object_mode()
106 self._mode = "object"
107 return self
108 end
109 --//--
111 --[[--
112 db_selector = -- same selector returned
113 <db_selector>:optional_object_mode()
115 Sets selector to single object mode (mode "opt_object" passed to "query" method of database handle). The selector is modified and returned.
117 --]]--
118 function selector_prototype:optional_object_mode()
119 self._mode = "opt_object"
120 return self
121 end
122 --//--
124 --[[--
125 db_selector = -- same selector returned
126 <db_selector>:empty_list_mode()
128 Sets selector to empty list mode. The selector is modified and returned. When using the selector, no SQL query will be issued, but instead an empty database result list is returned.
130 --]]--
131 function selector_prototype:empty_list_mode()
132 self._mode = "empty_list"
133 return self
134 end
135 --//--
137 --[[--
138 db_selector =
139 <db_selector>:add_with(
140 expression = expression,
141 selector = selector
142 )
144 Adds an WITH RECURSIVE expression to the selector. The selector is modified and returned.
145 --]]--
146 function selector_prototype:add_with(expression, selector)
147 add(self._with, {"$ AS ($)", {expression}, {selector}})
148 return self
149 end
150 --//--
152 --[[--
153 db_selector = -- same selector returned
154 <db_selector>:add_distinct_on(
155 expression -- expression as passed to "assemble_command"
156 )
158 Adds an DISTINCT ON expression to the selector. The selector is modified and returned.
160 --]]--
161 function selector_prototype:add_distinct_on(expression)
162 if self._distinct then
163 error("Can not combine DISTINCT with DISTINCT ON.")
164 end
165 add(self._distinct_on, expression)
166 return self
167 end
168 --//--
170 --[[--
171 db_selector = -- same selector returned
172 <db_selector>:set_distinct()
174 Sets selector to perform a SELECT DISTINCT instead of SELECT (ALL). The selector is modified and returned. This mode can not be combined with DISTINCT ON.
176 --]]--
177 function selector_prototype:set_distinct()
178 if #self._distinct_on > 0 then
179 error("Can not combine DISTINCT with DISTINCT ON.")
180 end
181 self._distinct = true
182 return self
183 end
184 --//--
186 --[[--
187 db_selector = -- same selector returned
188 <db_selector>:add_from(
189 expression, -- expression as passed to "assemble_command"
190 alias, -- optional alias expression as passed to "assemble_command"
191 condition -- optional condition expression as passed to "assemble_command"
192 )
194 Adds expressions for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.
196 This method is identical to "join".
198 --]]--
199 function selector_prototype:add_from(expression, alias, condition)
200 local first = (#self._from == 0)
201 if not first then
202 if condition then
203 add(self._from, "INNER JOIN")
204 else
205 add(self._from, "CROSS JOIN")
206 end
207 end
208 if getmetatable(expression) == selector_metatable then
209 if alias then
210 add(self._from, {'($) AS "$"', {expression}, {alias}})
211 else
212 add(self._from, {'($) AS "subquery"', {expression}})
213 end
214 else
215 if alias then
216 add(self._from, {'$ AS "$"', {expression}, {alias}})
217 else
218 add(self._from, expression)
219 end
220 end
221 if condition then
222 if first then
223 self:add_where(condition)
224 else
225 add(self._from, "ON")
226 add(self._from, condition)
227 end
228 end
229 return self
230 end
231 --//--
233 --[[--
234 db_selector = -- same selector returned
235 <db_selector>:add_where(
236 expression -- expression as passed to "assemble_command"
237 )
239 Adds expressions for WHERE clause to the selector. The selector is modified and returned. Multiple calls cause expressions to be AND-combined.
241 --]]--
242 function selector_prototype:add_where(expression)
243 add(self._where, expression)
244 return self
245 end
246 --//--
248 --[[--
249 db_selector = -- same selector returned
250 <db_selector>:add_group_by(
251 expression -- expression as passed to "assemble_command"
252 )
254 Adds expressions for GROUP BY clause to the selector. The selector is modified and returned.
256 --]]--
257 function selector_prototype:add_group_by(expression)
258 add(self._group_by, expression)
259 return self
260 end
261 --//--
263 --[[--
264 db_selector = -- same selector returned
265 <db_selector>:add_having(
266 expression -- expression as passed to "assemble_command"
267 )
269 Adds expressions for HAVING clause to the selector. The selector is modified and returned. Multiple calls cause expressions to be AND-combined.
271 --]]--
272 function selector_prototype:add_having(expression)
273 add(self._having, expression)
274 return self
275 end
276 --//--
278 --[[--
279 db_selector = -- same selector returned
280 <db_selector>:add_combine(
281 expression -- expression as passed to "assemble_command"
282 )
284 This function is used for UNION/INTERSECT/EXCEPT clauses. It does not need to be called directly. Use "union", "union_all", "intersect", "intersect_all", "except" and "except_all" instead.
286 --]]--
287 function selector_prototype:add_combine(expression)
288 add(self._combine, expression)
289 return self
290 end
291 --//--
293 --[[--
294 db_selector = -- same selector returned
295 <db_selector>:add_order_by(
296 expression -- expression as passed to "assemble_command"
297 )
299 Adds expressions for ORDER BY clause to the selector. The selector is modified and returned.
301 --]]--
302 function selector_prototype:add_order_by(expression)
303 add(self._order_by, expression)
304 return self
305 end
306 --//--
308 --[[--
309 db_selector = -- same selector returned
310 <db_selector>:limit(
311 count -- integer used as LIMIT
312 )
314 Limits the number of rows to a given number, by using LIMIT. The selector is modified and returned.
316 --]]--
317 function selector_prototype:limit(count)
318 if type(count) ~= "number" or count % 1 ~= 0 then
319 error("LIMIT must be an integer.")
320 end
321 self._limit = count
322 return self
323 end
324 --//--
326 --[[--
327 db_selector = -- same selector returned
328 <db_selector>:offset(
329 count -- integer used as OFFSET
330 )
332 Skips a given number of rows, by using OFFSET. The selector is modified and returned.
334 --]]--
335 function selector_prototype:offset(count)
336 if type(count) ~= "number" or count % 1 ~= 0 then
337 error("OFFSET must be an integer.")
338 end
339 self._offset = count
340 return self
341 end
342 --//--
344 --[[--
345 db_selector = -- same selector returned
346 <db_selector>:for_share()
348 Adds FOR SHARE to the statement, to share-lock all rows read. The selector is modified and returned.
350 --]]--
351 function selector_prototype:for_share()
352 self._read_lock.all = true
353 return self
354 end
355 --//--
357 --[[--
358 db_selector = -- same selector returned
359 <db_selector>:for_share_of(
360 expression -- expression as passed to "assemble_command"
361 )
363 Adds FOR SHARE OF to the statement, to share-lock all rows read by the named table(s). The selector is modified and returned.
365 --]]--
366 function selector_prototype:for_share_of(expression)
367 add(self._read_lock, expression)
368 return self
369 end
370 --//--
372 --[[--
373 db_selector = -- same selector returned
374 <db_selector>:for_update()
376 Adds FOR UPDATE to the statement, to exclusivly lock all rows read. The selector is modified and returned.
378 --]]--
379 function selector_prototype:for_update()
380 self._write_lock.all = true
381 return self
382 end
383 --//--
385 --[[--
386 db_selector = -- same selector returned
387 <db_selector>:for_update_of(
388 expression -- expression as passed to "assemble_command"
389 )
391 Adds FOR SHARE OF to the statement, to exclusivly lock all rows read by the named table(s). The selector is modified and returned.
393 --]]--
394 function selector_prototype:for_update_of(expression)
395 add(self._write_lock, expression)
396 return self
397 end
398 --//--
400 --[[--
401 db_selector = -- same selector returned
402 <db_selector>:reset_fields()
404 This method removes all fields added by method "add_field". The selector is modified and returned.
406 --]]--
407 function selector_prototype:reset_fields()
408 for idx in ipairs(self._fields) do
409 self._fields[idx] = nil
410 end
411 return self
412 end
413 --//--
415 --[[--
416 db_selector = -- same selector returned
417 <db_selector>:add_field(
418 expression, -- expression as passed to "assemble_command"
419 alias, -- optional alias expression as passed to "assemble_command"
420 option_list -- optional list of options (may contain strings "distinct" or "grouped")
421 )
423 Adds fields to the selector. The selector is modified and returned. The third argument can be a list of options. If option "distinct" is given, then "add_distinct_on" will be executed for the given field or alias. If option "grouped" is given, then "add_group_by" will be executed for the given field or alias.
425 --]]--
426 function selector_prototype:add_field(expression, alias, options)
427 if alias then
428 add(self._fields, {'$ AS "$"', {expression}, {alias}})
429 else
430 add(self._fields, expression)
431 end
432 if options then
433 for i, option in ipairs(options) do
434 if option == "distinct" then
435 if alias then
436 self:add_distinct_on('"' .. alias .. '"')
437 else
438 self:add_distinct_on(expression)
439 end
440 elseif option == "grouped" then
441 if alias then
442 self:add_group_by('"' .. alias .. '"')
443 else
444 self:add_group_by(expression)
445 end
446 else
447 error("Unknown option '" .. option .. "' to add_field method.")
448 end
449 end
450 end
451 return self
452 end
453 --//--
455 --[[--
456 db_selector = -- same selector returned
457 <db_selector>:join(
458 expression, -- expression as passed to "assemble_command"
459 alias, -- optional alias expression as passed to "assemble_command"
460 condition -- optional condition expression as passed to "assemble_command"
461 )
463 Adds expressions for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.
465 This method is identical to "add_from".
467 --]]--
468 function selector_prototype:join(...) -- NOTE: alias for add_from
469 return self:add_from(...)
470 end
471 --//--
473 --[[--
474 db_selector = -- same selector returned
475 <db_selector>:from(
476 expression, -- expression as passed to "assemble_command"
477 alias, -- optional alias expression as passed to "assemble_command"
478 condition -- optional condition expression as passed to "assemble_command"
479 )
481 Adds the first expression for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.
483 This method is identical to "add_from" or "join", except that an error is thrown, if there is already any FROM expression existent.
485 --]]--
486 function selector_prototype:from(expression, alias, condition)
487 if #self._from > 0 then
488 error("From-clause already existing (hint: try join).")
489 end
490 return self:join(expression, alias, condition)
491 end
492 --//--
494 --[[--
495 db_selector = -- same selector returned
496 <db_selector>:left_join(
497 expression, -- expression as passed to "assemble_command"
498 alias, -- optional alias expression as passed to "assemble_command"
499 condition -- optional condition expression as passed to "assemble_command"
500 )
502 Adds expressions for FROM clause to the selector using a LEFT OUTER JOIN. The selector is modified and returned.
504 --]]--
505 function selector_prototype:left_join(expression, alias, condition)
506 local first = (#self._from == 0)
507 if not first then
508 add(self._from, "LEFT OUTER JOIN")
509 end
510 if alias then
511 add(self._from, {'$ AS "$"', {expression}, {alias}})
512 else
513 add(self._from, expression)
514 end
515 if condition then
516 if first then
517 self:add_where(condition)
518 else
519 add(self._from, "ON")
520 add(self._from, condition)
521 end
522 end
523 return self
524 end
525 --//--
527 --[[--
528 db_selector = -- same selector returned
529 <db_selector>:union(
530 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
531 )
533 This method adds a UNION clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
535 --]]--
536 function selector_prototype:union(expression)
537 self:add_combine{"UNION $", {expression}}
538 return self
539 end
540 --//--
542 --[[--
543 db_selector = -- same selector returned
544 <db_selector>:union_all(
545 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
546 )
548 This method adds a UNION ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
550 --]]--
551 function selector_prototype:union_all(expression)
552 self:add_combine{"UNION ALL $", {expression}}
553 return self
554 end
555 --//--
557 --[[--
558 db_selector = -- same selector returned
559 <db_selector>:intersect(
560 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
561 )
563 This method adds an INTERSECT clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
565 --]]--
566 function selector_prototype:intersect(expression)
567 self:add_combine{"INTERSECT $", {expression}}
568 return self
569 end
570 --//--
572 --[[--
573 db_selector = -- same selector returned
574 <db_selector>:intersect_all(
575 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
576 )
578 This method adds an INTERSECT ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
580 --]]--
581 function selector_prototype:intersect_all(expression)
582 self:add_combine{"INTERSECT ALL $", {expression}}
583 return self
584 end
585 --//--
587 --[[--
588 db_selector = -- same selector returned
589 <db_selector>:except(
590 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
591 )
593 This method adds an EXCEPT clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
595 --]]--
596 function selector_prototype:except(expression)
597 self:add_combine{"EXCEPT $", {expression}}
598 return self
599 end
600 --//--
602 --[[--
603 db_selector = -- same selector returned
604 <db_selector>:except_all(
605 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE
606 )
608 This method adds an EXCEPT ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.
610 --]]--
611 function selector_prototype:except_all(expression)
612 self:add_combine{"EXCEPT ALL $", {expression}}
613 return self
614 end
615 --//--
617 --[[--
618 db_selector = -- same selector returned
619 <db_selector>:set_class(
620 class -- database class (model)
621 )
623 This method makes the selector to return database result lists or objects of the given database class (model). The selector is modified and returned.
625 --]]--
626 function selector_prototype:set_class(class)
627 self._class = class
628 return self
629 end
630 --//--
632 --[[--
633 db_selector = -- same selector returned
634 <db_selector>:attach(
635 mode, -- attachment type: "11" one to one, "1m" one to many, "m1" many to one
636 data2, -- other database result list or object, the results of this selector shall be attached with
637 field1, -- field name(s) in result list or object of this selector used for attaching
638 field2, -- field name(s) in "data2" used for attaching
639 ref1, -- name of reference field in the results of this selector after attaching
640 ref2 -- name of reference field in "data2" after attaching
641 )
643 This method causes database result lists or objects of this selector to be attached with other database result lists after execution. This method does not need to be called directly.
645 --]]--
646 function selector_prototype:attach(mode, data2, field1, field2, ref1, ref2)
647 self._attach = {
648 mode = mode,
649 data2 = data2,
650 field1 = field1,
651 field2 = field2,
652 ref1 = ref1,
653 ref2 = ref2
654 }
655 return self
656 end
657 --//--
659 function selector_metatable:__tostring()
660 local parts = {sep = " "}
661 if #self._with > 0 then
662 add(parts, {"WITH RECURSIVE $", self._with})
663 end
664 add(parts, "SELECT")
665 if self._distinct then
666 add(parts, "DISTINCT")
667 elseif #self._distinct_on > 0 then
668 add(parts, {"DISTINCT ON ($)", self._distinct_on})
669 end
670 add(parts, {"$", self._fields})
671 if #self._from > 0 then
672 add(parts, {"FROM $", self._from})
673 end
674 if #self._mode == "empty_list" then
675 add(parts, "WHERE FALSE")
676 elseif #self._where > 0 then
677 add(parts, {"WHERE ($)", self._where})
678 end
679 if #self._group_by > 0 then
680 add(parts, {"GROUP BY $", self._group_by})
681 end
682 if #self._having > 0 then
683 add(parts, {"HAVING ($)", self._having})
684 end
685 for i, v in ipairs(self._combine) do
686 add(parts, v)
687 end
688 if #self._order_by > 0 then
689 add(parts, {"ORDER BY $", self._order_by})
690 end
691 if self._mode == "empty_list" then
692 add(parts, "LIMIT 0")
693 elseif self._mode ~= "list" then
694 add(parts, "LIMIT 1")
695 elseif self._limit then
696 add(parts, "LIMIT " .. self._limit)
697 end
698 if self._offset then
699 add(parts, "OFFSET " .. self._offset)
700 end
701 if self._write_lock.all then
702 add(parts, "FOR UPDATE")
703 else
704 if self._read_lock.all then
705 add(parts, "FOR SHARE")
706 elseif #self._read_lock > 0 then
707 add(parts, {"FOR SHARE OF $", self._read_lock})
708 end
709 if #self._write_lock > 0 then
710 add(parts, {"FOR UPDATE OF $", self._write_lock})
711 end
712 end
713 return self._db_conn:assemble_command{"$", parts}
714 end
716 --[[--
717 db_error, -- database error object, or nil in case of success
718 result = -- database result list or object
719 <db_selector>:try_exec()
721 This method executes the selector on its database. First return value is an error object or nil in case of success. Second return value is the result list or object.
723 --]]--
724 function selector_prototype:try_exec()
725 if self._mode == "empty_list" then
726 if self._class then
727 return nil, self._class:create_list()
728 else
729 return nil, self._db_conn:create_list()
730 end
731 end
732 local db_error, db_result = self._db_conn:try_query(self, self._mode)
733 if db_error then
734 return db_error
735 elseif db_result then
736 if self._class then set_class(db_result, self._class) end
737 if self._attach then
738 attach(
739 self._attach.mode,
740 db_result,
741 self._attach.data2,
742 self._attach.field1,
743 self._attach.field2,
744 self._attach.ref1,
745 self._attach.ref2
746 )
747 end
748 return nil, db_result
749 else
750 return nil
751 end
752 end
753 --//--
755 --[[--
756 result = -- database result list or object
757 <db_selector>:exec()
759 This method executes the selector on its database. The result list or object is returned on success, otherwise an error is thrown.
761 --]]--
762 function selector_prototype:exec()
763 local db_error, result = self:try_exec()
764 if db_error then
765 db_error:escalate()
766 else
767 return result
768 end
769 end
770 --//--
772 --[[--
773 count = -- number of rows returned
774 <db_selector>:count()
776 This function wraps the given selector inside a subquery to count the number of rows returned by the database. NOTE: The result is cached inside the selector, thus the selector should NOT be modified afterwards.
778 --]]--
779 function selector_prototype:count()
780 if not self._count then
781 local count_selector = self:get_db_conn():new_selector()
782 count_selector:add_field('count(1)')
783 count_selector:add_from(self)
784 count_selector:single_object_mode()
785 self._count = count_selector:exec().count
786 end
787 return self._count
788 end
789 --//--
793 -----------------
794 -- attachments --
795 -----------------
797 local function attach_key(row, fields)
798 local t = type(fields)
799 if t == "string" then
800 return tostring(row[fields])
801 elseif t == "table" then
802 local r = {}
803 for idx, field in ipairs(fields) do
804 r[idx] = string.format("%q", row[field])
805 end
806 return table.concat(r)
807 else
808 error("Field information for 'mondelefant.attach' is neither a string nor a table.")
809 end
810 end
812 --[[--
813 mondelefant.attach(
814 mode, -- attachment type: "11" one to one, "1m" one to many, "m1" many to one
815 data1, -- first database result list or object
816 data2, -- second database result list or object
817 key1, -- field name(s) in first result list or object used for attaching
818 key2, -- field name(s) in second result list or object used for attaching
819 ref1, -- name of reference field to be set in first database result list or object
820 ref2 -- name of reference field to be set in second database result list or object
821 )
823 This function attaches database result lists/objects with each other. It does not need to be called directly.
825 --]]--
826 function attach(mode, data1, data2, key1, key2, ref1, ref2)
827 local many1, many2
828 if mode == "11" then
829 many1 = false
830 many2 = false
831 elseif mode == "1m" then
832 many1 = false
833 many2 = true
834 elseif mode == "m1" then
835 many1 = true
836 many2 = false
837 elseif mode == "mm" then
838 many1 = true
839 many2 = true
840 else
841 error("Unknown mode specified for 'mondelefant.attach'.")
842 end
843 local list1, list2
844 if data1._type == "object" then
845 list1 = { data1 }
846 elseif data1._type == "list" then
847 list1 = data1
848 else
849 error("First result data given to 'mondelefant.attach' is invalid.")
850 end
851 if data2._type == "object" then
852 list2 = { data2 }
853 elseif data2._type == "list" then
854 list2 = data2
855 else
856 error("Second result data given to 'mondelefant.attach' is invalid.")
857 end
858 local hash1 = {}
859 local hash2 = {}
860 if ref2 then
861 for i, row in ipairs(list1) do
862 local key = attach_key(row, key1)
863 local list = hash1[key]
864 if not list then list = {}; hash1[key] = list end
865 list[#list + 1] = row
866 end
867 end
868 if ref1 then
869 for i, row in ipairs(list2) do
870 local key = attach_key(row, key2)
871 local list = hash2[key]
872 if not list then list = {}; hash2[key] = list end
873 list[#list + 1] = row
874 end
875 for i, row in ipairs(list1) do
876 local key = attach_key(row, key1)
877 local matching_rows = hash2[key]
878 if many2 then
879 local list = data2._connection:create_list(matching_rows)
880 list._class = data2._class
881 row._ref[ref1] = list
882 elseif matching_rows and #matching_rows == 1 then
883 row._ref[ref1] = matching_rows[1]
884 else
885 row._ref[ref1] = false
886 end
887 end
888 end
889 if ref2 then
890 for i, row in ipairs(list2) do
891 local key = attach_key(row, key2)
892 local matching_rows = hash1[key]
893 if many1 then
894 local list = data1._connection:create_list(matching_rows)
895 list._class = data1._class
896 row._ref[ref2] = list
897 elseif matching_rows and #matching_rows == 1 then
898 row._ref[ref2] = matching_rows[1]
899 else
900 row._ref[ref2] = false
901 end
902 end
903 end
904 end
905 --//--
909 ------------------
910 -- model system --
911 ------------------
913 --[[--
914 <db_class>.primary_key
916 Primary key of a database class (model). Defaults to "id".
918 If the primary key is a tuple, then a sequence (table with integer keys mapped to the column names) must be used. If the primary key is contained in a JSON document within a table column, then a special object with the following fields is expected: {json_doc = "column_name", key = "field_name_within_json_object", type = "postgresql_type"}.
920 --]]--
921 class_prototype.primary_key = "id"
922 --//--
924 --[[--
925 <db_class>.document_column
927 Optional column name to redirect key lookups to. This can be used to allow for an easier access to fields of a JSON document.
929 --]]--
930 class_prototype.document_column = nil
931 --//--
933 --[[--
934 db_handle = -- database connection handle used by this class
935 <db_class>:get_db_conn()
937 By implementing this method for a particular model or overwriting it in the default prototype "mondelefant.class_prototype", classes are connected with a particular database. This method needs to return a database connection handle. If it is not overwritten, an error is thrown, when invoking this method.
939 --]]--
940 function class_prototype:get_db_conn()
941 error(
942 "Method mondelefant class(_prototype):get_db_conn() " ..
943 "has to be implemented."
944 )
945 end
946 --//--
948 --[[--
949 string = -- string of form '"schemaname"."tablename"' or '"tablename"'
950 <db_class>:get_qualified_table()
952 This method returns a string with the (double quoted) qualified table name used to store objects of this class.
954 --]]--
955 function class_prototype:get_qualified_table()
956 if not self.table then error "Table unknown." end
957 if self.schema then
958 return '"' .. self.schema .. '"."' .. self.table .. '"'
959 else
960 return '"' .. self.table .. '"'
961 end
962 end
963 --]]--
965 --[[--
966 string = -- single quoted string of form "'schemaname.tablename'" or "'tablename'"
967 <db_class>:get_qualified_table_literal()
969 This method returns a string with an SQL literal representing the given table. It causes ambiguities when the table name contains a dot (".") character.
971 --]]--
972 function class_prototype:get_qualified_table_literal()
973 if not self.table then error "Table unknown." end
974 if self.schema then
975 return self.schema .. '.' .. self.table
976 else
977 return self.table
978 end
979 end
980 --//--
982 --[[--
983 list = -- list of column names of primary key
984 <db_class>:get_primary_key_list()
986 This method returns a list of column names of the primary key.
988 --]]--
989 function class_prototype:get_primary_key_list()
990 local primary_key = self.primary_key
991 if type(primary_key) == "string" then
992 return {primary_key}
993 else
994 return primary_key
995 end
996 end
997 --//--
999 --[[--
1000 columns = -- list of columns
1001 <db_class>:get_columns()
1003 This method returns a list of column names of the table used for the class.
1005 --]]--
1006 function class_prototype:get_columns()
1007 if self._columns then
1008 return self._columns
1009 end
1010 local selector = self:get_db_conn():new_selector()
1011 selector:set_class(self)
1012 selector:from(self:get_qualified_table())
1013 selector:add_field("*")
1014 selector:add_where("FALSE")
1015 local db_result = selector:exec()
1016 local connection = db_result._connection
1017 local columns = {}
1018 for idx, info in ipairs(db_result._column_info) do
1019 local key = info.field_name
1020 local value = {
1021 name = key,
1022 type = connection.type_mappings[info.type]
1023 }
1024 columns[key] = value
1025 table.insert(columns, value)
1026 end
1027 self._columns = columns
1028 return columns
1029 end
1030 --//--
1032 --[[--
1033 selector = -- new selector for selecting objects of this class
1034 <db_class>:new_selector(
1035 db_conn -- optional(!) database connection handle, defaults to result of :get_db_conn()
1036 )
1038 This method creates a new selector for selecting objects of the class.
1040 --]]--
1041 function class_prototype:new_selector(db_conn)
1042 local selector = (db_conn or self:get_db_conn()):new_selector()
1043 selector:set_class(self)
1044 selector:from(self:get_qualified_table())
1045 selector:add_field(self:get_qualified_table() .. ".*")
1046 return selector
1047 end
1048 --//--
1050 --[[--
1051 db_list = -- database result being an empty list
1052 <db_class>:create_list()
1054 Creates an empty database result representing a list of objects of the given class.
1056 --]]--
1057 function class_prototype:create_list()
1058 local list = self:get_db_conn():create_list()
1059 list._class = self
1060 return list
1061 end
1062 --//--
1064 --[[--
1065 db_object = -- database object (instance of model)
1066 <db_class>:new()
1068 Creates a new object of the given class.
1070 --]]--
1071 function class_prototype:new()
1072 local object = self:get_db_conn():create_object()
1073 object._class = self
1074 object._new = true
1075 return object
1076 end
1077 --//--
1079 --[[--
1080 db_error = -- database error object, or nil in case of success
1081 <db_object>:try_save()
1083 This method saves changes to an object in the database. Returns nil on success, otherwise an error object is returned.
1085 --]]--
1086 function class_prototype.object:try_save()
1087 if not self._class then
1088 error("Cannot save object: No class information available.")
1089 end
1090 local primary_key = self._class:get_primary_key_list()
1091 local primary_key_sql = { sep = ", " }
1092 if primary_key.json_doc then
1093 primary_key_sql[1] = {
1094 '("$"->>?)::$ AS "json_key"',
1095 {primary_key.json_doc}, primary_key.key, {primary_key.type}
1096 }
1097 else
1098 for idx, value in ipairs(primary_key) do
1099 primary_key_sql[idx] = '"' .. value .. '"'
1100 end
1101 end
1102 if self._new then
1103 local fields = {sep = ", "}
1104 local values = {sep = ", "}
1105 for key in pairs(self._dirty or {}) do
1106 add(fields, {'"$"', {key}})
1107 add(values, {'?', self[key]})
1108 end
1109 local db_error, db_result
1110 if #fields == 0 then
1111 db_error, db_result = self._connection:try_query(
1112 {
1113 'INSERT INTO $ DEFAULT VALUES RETURNING $',
1114 {self._class:get_qualified_table()},
1115 primary_key_sql
1116 },
1117 "object"
1118 )
1119 else
1120 db_error, db_result = self._connection:try_query(
1121 {
1122 'INSERT INTO $ ($) VALUES ($) RETURNING $',
1123 {self._class:get_qualified_table()},
1124 fields,
1125 values,
1126 primary_key_sql
1127 },
1128 "object"
1129 )
1130 end
1131 if db_error then
1132 return db_error
1133 end
1134 if primary_key.json_doc then
1135 self[primary_key.json_doc][primary_key.key] = db_result.json_key
1136 else
1137 for idx, value in ipairs(primary_key) do
1138 self[value] = db_result[value]
1139 end
1140 end
1141 self._new = false
1142 else
1143 local command_sets = {sep = ", "}
1144 for key, mutability_state in pairs(self._dirty or {}) do
1145 if
1146 mutability_state == true or (
1147 verify_mutability_state and
1148 verify_mutability_state(self[key], mutability_state)
1149 )
1150 then
1151 add(command_sets, {'"$" = ?', {key}, self[key]})
1152 self._dirty[key] = true -- always dirty in case of later error
1153 end
1154 end
1155 if #command_sets >= 1 then
1156 local primary_key_compare = {sep = " AND "}
1157 if primary_key.json_doc then
1158 primary_key_compare[1] = {
1159 '("$"->>?)::$ = ?',
1160 {primary_key.json_doc}, primary_key.key, {primary_key.type},
1161 self[primary_key.json_doc][primary_key.key]
1162 }
1163 else
1164 for idx, value in ipairs(primary_key) do
1165 primary_key_compare[idx] = {
1166 "$ = ?",
1167 {'"' .. value .. '"'},
1168 self[value]
1169 }
1170 end
1171 end
1172 local db_error = self._connection:try_query{
1173 'UPDATE $ SET $ WHERE $',
1174 {self._class:get_qualified_table()},
1175 command_sets,
1176 primary_key_compare
1177 }
1178 if db_error then
1179 return db_error
1180 end
1181 end
1182 end
1183 for key in pairs(self._dirty or {}) do
1184 if save_mutability_state then
1185 self._dirty[key] =
1186 save_mutability_state and save_mutability_state(self[key]) or nil
1187 end
1188 end
1189 return nil
1190 end
1191 --//--
1193 --[[--
1194 <db_object>:save()
1196 This method saves changes to an object in the database. Throws error, unless successful.
1198 --]]--
1199 function class_prototype.object:save()
1200 local db_error = self:try_save()
1201 if db_error then
1202 db_error:escalate()
1203 end
1204 return self
1205 end
1206 --//--
1208 --[[--
1209 db_error = -- database error object, or nil in case of success
1210 <db_object>:try_destroy()
1212 This method deletes an object in the database. Returns nil on success, otherwise an error object is returned.
1214 --]]--
1215 function class_prototype.object:try_destroy()
1216 if not self._class then
1217 error("Cannot destroy object: No class information available.")
1218 end
1219 local primary_key = self._class:get_primary_key_list()
1220 local primary_key_compare = {sep = " AND "}
1221 if primary_key.json_doc then
1222 primary_key_compare[1] = {
1223 '("$"->>?)::$ = ?',
1224 {primary_key.json_doc}, primary_key.key, {primary_key.type},
1225 self[primary_key.json_doc][primary_key.key]
1226 }
1227 else
1228 for idx, value in ipairs(primary_key) do
1229 primary_key_compare[idx] = {
1230 "$ = ?",
1231 {'"' .. value .. '"'},
1232 self[value]
1233 }
1234 end
1235 end
1236 return self._connection:try_query{
1237 'DELETE FROM $ WHERE $',
1238 {self._class:get_qualified_table()},
1239 primary_key_compare
1240 }
1241 end
1242 --//--
1244 --[[--
1245 <db_object>:destroy()
1247 This method deletes an object in the database. Throws error, unless successful.
1249 --]]--
1250 function class_prototype.object:destroy()
1251 local db_error = self:try_destroy()
1252 if db_error then
1253 db_error:escalate()
1254 end
1255 return self
1256 end
1257 --//--
1259 --[[--
1260 db_selector =
1261 <db_list>:get_reference_selector(
1262 ref_name, -- name of reference (e.g. "children")
1263 options, -- table options passed to the reference loader (e.g. { order = ... })
1264 ref_alias, -- optional alias for the reference (e.g. "ordered_children")
1265 back_ref_alias -- back reference name (e.g. "parent")
1266 )
1268 This method returns a special selector for selecting referenced objects. It is prepared in a way, that on execution of the selector, all returned objects are attached with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.
1270 This method is not only available for database result lists but also for database result objects.
1272 --]]--
1273 function class_prototype.list:get_reference_selector(
1274 ref_name, options, ref_alias, back_ref_alias
1275 )
1276 local ref_info = self._class.references[ref_name]
1277 if not ref_info then
1278 error('Reference with name "' .. ref_name .. '" not found.')
1279 end
1280 local selector = ref_info.selector_generator(self, options or {})
1281 local mode = ref_info.mode
1282 if mode == "mm" or mode == "1m" then
1283 mode = "m1"
1284 elseif mode == "m1" then
1285 mode = "1m"
1286 end
1287 local ref_alias = ref_alias
1288 if ref_alias == false then
1289 ref_alias = nil
1290 elseif ref_alias == nil then
1291 ref_alias = ref_name
1292 end
1293 local back_ref_alias
1294 if back_ref_alias == false then
1295 back_ref_alias = nil
1296 elseif back_ref_alias == nil then
1297 back_ref_alias = ref_info.back_ref
1298 end
1299 selector:attach(
1300 mode,
1301 self,
1302 ref_info.that_key, ref_info.this_key,
1303 back_ref_alias or ref_info.back_ref, ref_alias or ref_name
1304 )
1305 return selector
1306 end
1307 --//--
1309 --[[--
1310 db_list_or_object =
1311 <db_list>:load(
1312 ref_name, -- name of reference (e.g. "children")
1313 options, -- table options passed to the reference loader (e.g. { order = ... })
1314 ref_alias, -- optional alias for the reference (e.g. "ordered_children")
1315 back_ref_alias -- back reference name (e.g. "parent")
1316 )
1318 This method loads referenced objects and attaches them with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.
1320 This method is not only available for database result lists but also for database result objects.
1322 --]]--
1323 function class_prototype.list.load(...)
1324 return class_prototype.list.get_reference_selector(...):exec()
1325 end
1326 --//--
1328 --[[--
1329 db_object =
1330 <db_object>:get_reference_selector(
1331 ref_name, -- name of reference (e.g. "children")
1332 options, -- table options passed to the reference loader (e.g. { order = ... })
1333 ref_alias, -- optional alias for the reference (e.g. "ordered_children")
1334 back_ref_alias -- back reference name (e.g. "parent")
1335 )
1337 This method returns a special selector for selecting referenced objects. It is prepared in a way, that on execution of the selector, all returned objects are attached with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.
1339 This method is not only available for database result objects but also for database result lists.
1341 --]]--
1342 function class_prototype.object:get_reference_selector(...)
1343 local list = self._class:create_list()
1344 list[1] = self
1345 return list:get_reference_selector(...)
1346 end
1347 --//--
1349 --[[--
1350 db_list_or_object =
1351 <db_object>:load(
1352 ref_name, -- name of reference (e.g. "children")
1353 options, -- table options passed to the reference loader (e.g. { order = ... })
1354 ref_alias, -- optional alias for the reference (e.g. "ordered_children")
1355 back_ref_alias -- back reference name (e.g. "parent")
1356 )
1358 This method loads referenced objects and attaches them with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.
1360 This method is not only available for database result objects but also for database result lists. Calling this method for objects is unneccessary, unless additional options and/or an alias is used.
1362 --]]--
1363 function class_prototype.object.load(...)
1364 return class_prototype.object.get_reference_selector(...):exec()
1365 end
1366 --//--
1368 --[[--
1369 db_class = -- same class returned
1370 <db_class>:add_reference{
1371 mode = mode, -- "11", "1m", "m1", or "mm" (one/many to one/many)
1372 to = to, -- referenced class (model), optionally as string or function returning the value (avoids autoload)
1373 this_key = this_key, -- name of key in this class (model)
1374 that_key = that_key, -- name of key in the other class (model) ("to" argument)
1375 ref = ref, -- name of reference in this class, referring to the other class
1376 back_ref = back_ref, -- name of reference in other class, referring to this class
1377 default_order = default_order, -- expression as passed to "assemble_command" used for sorting
1378 selector_generator = selector_generator, -- alternative function used as selector generator (use only, when you know what you are doing)
1379 connected_by_table = connected_by_table, -- connecting table used for many to many relations
1380 connected_by_this_key = connected_by_this_key, -- key in connecting table referring to "this_key" of this class (model)
1381 connected_by_that_key = connected_by_that_key -- key in connecting table referring to "that_key" in other class (model) ("to" argument)
1382 }
1384 Denotes a reference from one database class to another database class (model to model relation). There are 4 possible types of references: one-to-one (mode = "11"), one-to-many (mode = "1m"), many-to-one ("m1"), and many-to-many ("mm"). References usually should be defined in both models, which are related to each other, with mirrored mode (i.e. "1m" in one model, and "m1" in the other). One-to-one and one-to-many references may have a "back_ref" setting, which causes that loaded objects of the referenced class, refer back to the originating object. One-to-many and many-to-many references may have a "default_order" setting, which selects the default order for selected objects. When adding a many-to-many reference, the argument "connected_by_table", "connected_by_this_key" and "connected_by_that_key" must be set additionally.
1386 --]]--
1387 function class_prototype:add_reference(args)
1388 local selector_generator = args.selector_generator
1389 local mode = args.mode
1390 local to = args.to
1391 local this_key = args.this_key
1392 local that_key = args.that_key
1393 local connected_by_table = args.connected_by_table -- TODO: split to table and schema
1394 local connected_by_this_key = args.connected_by_this_key
1395 local connected_by_that_key = args.connected_by_that_key
1396 local ref = args.ref
1397 local back_ref = args.back_ref
1398 local default_order = args.default_order
1399 local model
1400 local function get_model()
1401 if not model then
1402 if type(to) == "string" then
1403 model = _G
1404 for path_element in string.gmatch(to, "[^.]+") do
1405 model = model[path_element]
1406 end
1407 elseif type(to) == "function" then
1408 model = to()
1409 else
1410 model = to
1411 end
1412 end
1413 if not model or model == _G then
1414 error("Could not get model for reference.")
1415 end
1416 return model
1417 end
1418 self.references[ref] = {
1419 mode = mode,
1420 this_key = this_key,
1421 that_key = connected_by_table and "mm_ref_" or that_key,
1422 ref = ref,
1423 back_ref = back_ref,
1424 selector_generator = selector_generator or function(list, options)
1425 -- TODO: support tuple keys
1426 local options = options or {}
1427 local model = get_model()
1428 -- TODO: too many records cause PostgreSQL command stack overflow
1429 local ids = { sep = ", " }
1430 for i, object in ipairs(list) do
1431 local id = object[this_key]
1432 if id ~= nil then
1433 ids[#ids+1] = {"?", id}
1434 end
1435 end
1436 if #ids == 0 then
1437 return model:new_selector():empty_list_mode()
1438 end
1439 local selector = model:new_selector()
1440 if connected_by_table then
1441 selector:join(
1442 connected_by_table,
1443 nil,
1444 {
1445 '$."$" = $."$"',
1446 {connected_by_table},
1447 {connected_by_that_key},
1448 {model:get_qualified_table()},
1449 {that_key}
1450 }
1451 )
1452 selector:add_field(
1453 {
1454 '$."$"',
1455 {connected_by_table},
1456 {connected_by_this_key}
1457 },
1458 'mm_ref_'
1459 )
1460 selector:add_where{
1461 '$."$" IN ($)',
1462 {connected_by_table},
1463 {connected_by_this_key},
1464 ids
1465 }
1466 else
1467 selector:add_where{'$."$" IN ($)', {model:get_qualified_table()}, {that_key}, ids}
1468 end
1469 if options.order == nil and default_order then
1470 selector:add_order_by(default_order)
1471 elseif options.order then
1472 selector:add_order_by(options.order)
1473 end
1474 return selector
1475 end
1476 }
1477 if mode == "m1" or mode == "11" then
1478 self.foreign_keys[this_key] = ref
1479 end
1480 return self
1481 end
1482 --//--
1484 return _M