# 2010 September 20 # # The author disclaims copyright to this source code. In place of # a legal notice, here is a blessing: # # May you do good and not evil. # May you find forgiveness for yourself and forgive others. # May you share freely, never taking more than you give. # #*********************************************************************** # # This file implements tests to verify that the "testable statements" in # the lang_update.html document are correct. # set testdir [file dirname $argv0] source $testdir/tester.tcl #-------------------- # Test organization: # # e_update-1.*: Test statements describing the workings of UPDATE statements. # # e_update-2.*: Test the restrictions on the UPDATE statement syntax that # can be used within triggers. # # e_update-3.*: Test the special LIMIT/OFFSET and ORDER BY clauses that can # be used with UPDATE when SQLite is compiled with # SQLITE_ENABLE_UPDATE_DELETE_LIMIT. # forcedelete test.db2 do_execsql_test e_update-0.0 { ATTACH 'test.db2' AS aux; CREATE TABLE t1(a, b); CREATE TABLE t2(a, b, c); CREATE TABLE t3(a, b UNIQUE); CREATE TABLE t6(x, y); CREATE INDEX i1 ON t1(a); CREATE TEMP TABLE t4(x, y); CREATE TEMP TABLE t6(x, y); CREATE TABLE aux.t1(a, b); CREATE TABLE aux.t5(a, b); } {} proc do_update_tests {args} { uplevel do_select_tests $args } # EVIDENCE-OF: R-62337-45828 -- syntax diagram update-stmt # do_update_tests e_update-0 { 1 "UPDATE t1 SET a=10" {} 2 "UPDATE t1 SET a=10, b=5" {} 3 "UPDATE t1 SET a=10 WHERE b=5" {} 4 "UPDATE t1 SET b=5,a=10 WHERE 1" {} 5 "UPDATE main.t1 SET a=10" {} 6 "UPDATE main.t1 SET a=10, b=5" {} 7 "UPDATE main.t1 SET a=10 WHERE b=5" {} 9 "UPDATE OR ROLLBACK t1 SET a=10" {} 10 "UPDATE OR ROLLBACK t1 SET a=10, b=5" {} 11 "UPDATE OR ROLLBACK t1 SET a=10 WHERE b=5" {} 12 "UPDATE OR ROLLBACK t1 SET b=5,a=10 WHERE 1" {} 13 "UPDATE OR ROLLBACK main.t1 SET a=10" {} 14 "UPDATE OR ROLLBACK main.t1 SET a=10, b=5" {} 15 "UPDATE OR ROLLBACK main.t1 SET a=10 WHERE b=5" {} 16 "UPDATE OR ROLLBACK main.t1 SET b=5,a=10 WHERE 1" {} 17 "UPDATE OR ABORT t1 SET a=10" {} 18 "UPDATE OR ABORT t1 SET a=10, b=5" {} 19 "UPDATE OR ABORT t1 SET a=10 WHERE b=5" {} 20 "UPDATE OR ABORT t1 SET b=5,a=10 WHERE 1" {} 21 "UPDATE OR ABORT main.t1 SET a=10" {} 22 "UPDATE OR ABORT main.t1 SET a=10, b=5" {} 23 "UPDATE OR ABORT main.t1 SET a=10 WHERE b=5" {} 24 "UPDATE OR ABORT main.t1 SET b=5,a=10 WHERE 1" {} 25 "UPDATE OR REPLACE t1 SET a=10" {} 26 "UPDATE OR REPLACE t1 SET a=10, b=5" {} 27 "UPDATE OR REPLACE t1 SET a=10 WHERE b=5" {} 28 "UPDATE OR REPLACE t1 SET b=5,a=10 WHERE 1" {} 29 "UPDATE OR REPLACE main.t1 SET a=10" {} 30 "UPDATE OR REPLACE main.t1 SET a=10, b=5" {} 31 "UPDATE OR REPLACE main.t1 SET a=10 WHERE b=5" {} 32 "UPDATE OR REPLACE main.t1 SET b=5,a=10 WHERE 1" {} 33 "UPDATE OR FAIL t1 SET a=10" {} 34 "UPDATE OR FAIL t1 SET a=10, b=5" {} 35 "UPDATE OR FAIL t1 SET a=10 WHERE b=5" {} 36 "UPDATE OR FAIL t1 SET b=5,a=10 WHERE 1" {} 37 "UPDATE OR FAIL main.t1 SET a=10" {} 38 "UPDATE OR FAIL main.t1 SET a=10, b=5" {} 39 "UPDATE OR FAIL main.t1 SET a=10 WHERE b=5" {} 40 "UPDATE OR FAIL main.t1 SET b=5,a=10 WHERE 1" {} 41 "UPDATE OR IGNORE t1 SET a=10" {} 42 "UPDATE OR IGNORE t1 SET a=10, b=5" {} 43 "UPDATE OR IGNORE t1 SET a=10 WHERE b=5" {} 44 "UPDATE OR IGNORE t1 SET b=5,a=10 WHERE 1" {} 45 "UPDATE OR IGNORE main.t1 SET a=10" {} 46 "UPDATE OR IGNORE main.t1 SET a=10, b=5" {} 47 "UPDATE OR IGNORE main.t1 SET a=10 WHERE b=5" {} 48 "UPDATE OR IGNORE main.t1 SET b=5,a=10 WHERE 1" {} } # EVIDENCE-OF: R-38515-45264 An UPDATE statement is used to modify a # subset of the values stored in zero or more rows of the database table # identified by the qualified-table-name specified as part of the UPDATE # statement. # # Test cases e_update-1.1.1.* test the "identified by the # qualified-table-name" part of the statement above. Tests # e_update-1.1.2.* show that the "zero or more rows" part is # accurate. # do_execsql_test e_update-1.1.0 { INSERT INTO main.t1 VALUES(1, 'i'); INSERT INTO main.t1 VALUES(2, 'ii'); INSERT INTO main.t1 VALUES(3, 'iii'); INSERT INTO aux.t1 VALUES(1, 'I'); INSERT INTO aux.t1 VALUES(2, 'II'); INSERT INTO aux.t1 VALUES(3, 'III'); } {} do_update_tests e_update-1.1 { 1.1 "UPDATE t1 SET a = a+1; SELECT * FROM t1" {2 i 3 ii 4 iii} 1.2 "UPDATE main.t1 SET a = a+1; SELECT * FROM main.t1" {3 i 4 ii 5 iii} 1.3 "UPDATE aux.t1 SET a = a+1; SELECT * FROM aux.t1" {2 I 3 II 4 III} 2.1 "UPDATE t1 SET a = a+1 WHERE a = 1; SELECT * FROM t1" {3 i 4 ii 5 iii} 2.2 "UPDATE t1 SET a = a+1 WHERE a = 4; SELECT * FROM t1" {3 i 5 ii 5 iii} } # EVIDENCE-OF: R-55869-30521 If the UPDATE statement does not have a # WHERE clause, all rows in the table are modified by the UPDATE. # do_execsql_test e_update-1.2.0 { DELETE FROM main.t1; INSERT INTO main.t1 VALUES(1, 'i'); INSERT INTO main.t1 VALUES(2, 'ii'); INSERT INTO main.t1 VALUES(3, 'iii'); } {} do_update_tests e_update-1.2 { 1 "UPDATE t1 SET b = 'roman' ; SELECT * FROM t1" {1 roman 2 roman 3 roman} 2 "UPDATE t1 SET a = 'greek' ; SELECT * FROM t1" {greek roman greek roman greek roman} } # EVIDENCE-OF: R-42117-40023 Otherwise, the UPDATE affects only those # rows for which the result of evaluating the WHERE clause expression as # a boolean expression is true. # do_execsql_test e_update-1.3.0 { DELETE FROM main.t1; INSERT INTO main.t1 VALUES(NULL, ''); INSERT INTO main.t1 VALUES(1, 'i'); INSERT INTO main.t1 VALUES(2, 'ii'); INSERT INTO main.t1 VALUES(3, 'iii'); } {} do_update_tests e_update-1.3 { 1 "UPDATE t1 SET b = 'roman' WHERE a<2 ; SELECT * FROM t1" {{} {} 1 roman 2 ii 3 iii} 2 "UPDATE t1 SET b = 'egyptian' WHERE (a-3)/10.0 ; SELECT * FROM t1" {{} {} 1 egyptian 2 egyptian 3 iii} 3 "UPDATE t1 SET b = 'macedonian' WHERE a; SELECT * FROM t1" {{} {} 1 macedonian 2 macedonian 3 macedonian} 4 "UPDATE t1 SET b = 'lithuanian' WHERE a IS NULL; SELECT * FROM t1" {{} lithuanian 1 macedonian 2 macedonian 3 macedonian} } # EVIDENCE-OF: R-58129-20729 It is not an error if the WHERE clause does # not evaluate to true for any row in the table - this just means that # the UPDATE statement affects zero rows. # do_execsql_test e_update-1.4.0 { DELETE FROM main.t1; INSERT INTO main.t1 VALUES(NULL, ''); INSERT INTO main.t1 VALUES(1, 'i'); INSERT INTO main.t1 VALUES(2, 'ii'); INSERT INTO main.t1 VALUES(3, 'iii'); } {} do_update_tests e_update-1.4 -query { SELECT * FROM t1 } { 1 "UPDATE t1 SET b = 'burmese' WHERE a=5" {{} {} 1 i 2 ii 3 iii} 2 "UPDATE t1 SET b = 'burmese' WHERE length(b)<1 AND a IS NOT NULL" {{} {} 1 i 2 ii 3 iii} 3 "UPDATE t1 SET b = 'burmese' WHERE 0" {{} {} 1 i 2 ii 3 iii} 4 "UPDATE t1 SET b = 'burmese' WHERE (SELECT a FROM t1 WHERE rowid=1)" {{} {} 1 i 2 ii 3 iii} } # EVIDENCE-OF: R-40598-36595 For each affected row, the named columns # are set to the values found by evaluating the corresponding scalar # expressions. # # EVIDENCE-OF: R-40472-60438 Columns that do not appear in the list of # assignments are left unmodified. # do_execsql_test e_update-1.5.0 { INSERT INTO t2(rowid, a, b, c) VALUES(1, 3, 1, 4); INSERT INTO t2(rowid, a, b, c) VALUES(2, 1, 5, 9); INSERT INTO t2(rowid, a, b, c) VALUES(3, 2, 6, 5); } {} do_update_tests e_update-1.5 -query { SELECT * FROM t2 } { 1 "UPDATE t2 SET c = 1+1 WHERE a=2" {3 1 4 1 5 9 2 6 2} 2 "UPDATE t2 SET b = 4/2, c=CAST((0.4*5) AS INTEGER) WHERE a<3" {3 1 4 1 2 2 2 2 2} 3 "UPDATE t2 SET a = 1" {1 1 4 1 2 2 1 2 2} 4 "UPDATE t2 SET b = (SELECT count(*)+2 FROM t2), c = 24/3+1 WHERE rowid=2" {1 1 4 1 5 9 1 2 2} 5 "UPDATE t2 SET a = 3 WHERE c = 4" {3 1 4 1 5 9 1 2 2} 6 "UPDATE t2 SET a = b WHERE rowid>2" {3 1 4 1 5 9 2 2 2} 6 "UPDATE t2 SET b=6, c=5 WHERE a=b AND b=c" {3 1 4 1 5 9 2 6 5} } # EVIDENCE-OF: R-34751-18293 If a single column-name appears more than # once in the list of assignment expressions, all but the rightmost # occurrence is ignored. # do_update_tests e_update-1.6 -query { SELECT * FROM t2 } { 1 "UPDATE t2 SET c=5, c=6, c=7 WHERE rowid=1" {3 1 7 1 5 9 2 6 5} 2 "UPDATE t2 SET c=7, c=6, c=5 WHERE rowid=1" {3 1 5 1 5 9 2 6 5} 3 "UPDATE t2 SET c=5, b=6, c=7 WHERE rowid=1" {3 6 7 1 5 9 2 6 5} } # EVIDENCE-OF: R-36239-04077 The scalar expressions may refer to columns # of the row being updated. # # EVIDENCE-OF: R-04558-24451 In this case all scalar expressions are # evaluated before any assignments are made. # do_execsql_test e_update-1.7.0 { DELETE FROM t2; INSERT INTO t2(rowid, a, b, c) VALUES(1, 3, 1, 4); INSERT INTO t2(rowid, a, b, c) VALUES(2, 1, 5, 9); INSERT INTO t2(rowid, a, b, c) VALUES(3, 2, 6, 5); } {} do_update_tests e_update-1.7 -query { SELECT * FROM t2 } { 1 "UPDATE t2 SET a=b+c" {5 1 4 14 5 9 11 6 5} 2 "UPDATE t2 SET a=b, b=a" {1 5 4 5 14 9 6 11 5} 3 "UPDATE t2 SET a=c||c, c=NULL" {44 5 {} 99 14 {} 55 11 {}} } # EVIDENCE-OF: R-12619-24112 The optional conflict-clause allows the # user to nominate a specific constraint conflict resolution algorithm # to use during this one UPDATE command. # do_execsql_test e_update-1.8.0 { DELETE FROM t3; INSERT INTO t3 VALUES(1, 'one'); INSERT INTO t3 VALUES(2, 'two'); INSERT INTO t3 VALUES(3, 'three'); INSERT INTO t3 VALUES(4, 'four'); } {} foreach {tn sql error ac data } { 1 "UPDATE t3 SET b='one' WHERE a=3" {column b is not unique} 1 {1 one 2 two 3 three 4 four} 2 "UPDATE OR REPLACE t3 SET b='one' WHERE a=3" {} 1 {2 two 3 one 4 four} 3 "UPDATE OR FAIL t3 SET b='three'" {column b is not unique} 1 {2 three 3 one 4 four} 4 "UPDATE OR IGNORE t3 SET b='three' WHERE a=3" {} 1 {2 three 3 one 4 four} 5 "UPDATE OR ABORT t3 SET b='three' WHERE a=3" {column b is not unique} 1 {2 three 3 one 4 four} 6 "BEGIN" {} 0 {2 three 3 one 4 four} 7 "UPDATE t3 SET b='three' WHERE a=3" {column b is not unique} 0 {2 three 3 one 4 four} 8 "UPDATE OR ABORT t3 SET b='three' WHERE a=3" {column b is not unique} 0 {2 three 3 one 4 four} 9 "UPDATE OR FAIL t3 SET b='two'" {column b is not unique} 0 {2 two 3 one 4 four} 10 "UPDATE OR IGNORE t3 SET b='four' WHERE a=3" {} 0 {2 two 3 one 4 four} 11 "UPDATE OR REPLACE t3 SET b='four' WHERE a=3" {} 0 {2 two 3 four} 12 "UPDATE OR ROLLBACK t3 SET b='four'" {column b is not unique} 1 {2 three 3 one 4 four} } { do_catchsql_test e_update-1.8.$tn.1 $sql [list [expr {$error!=""}] $error] do_execsql_test e_update-1.8.$tn.2 {SELECT * FROM t3} [list {*}$data] do_test e_update-1.8.$tn.3 {sqlite3_get_autocommit db} $ac } # EVIDENCE-OF: R-12123-54095 The table-name specified as part of an # UPDATE statement within a trigger body must be unqualified. # # EVIDENCE-OF: R-09690-36749 In other words, the database-name. prefix # on the table name of the UPDATE is not allowed within triggers. # do_update_tests e_update-2.1 -error { qualified table names are not allowed on INSERT, UPDATE, and DELETE statements within triggers } { 1 { CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN UPDATE main.t2 SET a=1, b=2, c=3; END; } {} 2 { CREATE TRIGGER tr1 BEFORE UPDATE ON t2 BEGIN UPDATE aux.t1 SET a=1, b=2; END; } {} 3 { CREATE TRIGGER tr1 AFTER DELETE ON t4 BEGIN UPDATE main.t1 SET a=1, b=2; END; } {} } # EVIDENCE-OF: R-06085-13761 Unless the table to which the trigger is # attached is in the TEMP database, the table being updated by the # trigger program must reside in the same database as it. # do_update_tests e_update-2.2 -error { no such table: %s } { 1 { CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN UPDATE t4 SET x=x+1; END; INSERT INTO t1 VALUES(1, 2); } "main.t4" 2 { CREATE TRIGGER aux.tr1 AFTER INSERT ON t5 BEGIN UPDATE t4 SET x=x+1; END; INSERT INTO t5 VALUES(1, 2); } "aux.t4" } do_execsql_test e_update-2.2.X { DROP TRIGGER tr1; DROP TRIGGER aux.tr1; } {} # EVIDENCE-OF: R-29512-54644 If the table to which the trigger is # attached is in the TEMP database, then the unqualified name of the # table being updated is resolved in the same way as it is for a # top-level statement (by searching first the TEMP database, then the # main database, then any other databases in the order they were # attached). # do_execsql_test e_update-2.3.0 { SELECT 'main', tbl_name FROM main.sqlite_master WHERE type = 'table'; SELECT 'temp', tbl_name FROM sqlite_temp_master WHERE type = 'table'; SELECT 'aux', tbl_name FROM aux.sqlite_master WHERE type = 'table'; } [list {*}{ main t1 main t2 main t3 main t6 temp t4 temp t6 aux t1 aux t5 }] do_execsql_test e_update-2.3.1 { DELETE FROM main.t6; DELETE FROM temp.t6; INSERT INTO main.t6 VALUES(1, 2); INSERT INTO temp.t6 VALUES(1, 2); CREATE TRIGGER temp.tr1 AFTER INSERT ON t4 BEGIN UPDATE t6 SET x=x+1; END; INSERT INTO t4 VALUES(1, 2); SELECT * FROM main.t6; SELECT * FROM temp.t6; } {1 2 2 2} do_execsql_test e_update-2.3.2 { DELETE FROM main.t1; DELETE FROM aux.t1; INSERT INTO main.t1 VALUES(1, 2); INSERT INTO aux.t1 VALUES(1, 2); CREATE TRIGGER temp.tr2 AFTER DELETE ON t4 BEGIN UPDATE t1 SET a=a+1; END; DELETE FROM t4; SELECT * FROM main.t1; SELECT * FROM aux.t1; } {2 2 1 2} do_execsql_test e_update-2.3.3 { DELETE FROM aux.t5; INSERT INTO aux.t5 VALUES(1, 2); INSERT INTO t4 VALUES('x', 'y'); CREATE TRIGGER temp.tr3 AFTER UPDATE ON t4 BEGIN UPDATE t5 SET a=a+1; END; UPDATE t4 SET x=10; SELECT * FROM aux.t5; } {2 2} # EVIDENCE-OF: R-19619-42762 The INDEXED BY and NOT INDEXED clauses are # not allowed on UPDATE statements within triggers. # do_update_tests e_update-2.4 -error { the %s %s clause is not allowed on UPDATE or DELETE statements within triggers } { 1 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 INDEXED BY i1 SET a=a+1; END; } {INDEXED BY} 2 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 NOT INDEXED SET a=a+1; END; } {NOT INDEXED} } ifcapable update_delete_limit { # EVIDENCE-OF: R-57359-59558 The LIMIT and ORDER BY clauses for UPDATE # are unsupported within triggers, regardless of the compilation options # used to build SQLite. # do_update_tests e_update-2.5 -error { near "%s": syntax error } { 1 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 SET a=a+1 LIMIT 10; END; } {LIMIT} 2 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 SET a=a+1 ORDER BY a LIMIT 10; END; } {ORDER} 3 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 SET a=a+1 ORDER BY a LIMIT 10 OFFSET 2; END; } {ORDER} 4 { CREATE TRIGGER tr1 AFTER INSERT ON t2 BEGIN UPDATE t1 SET a=a+1 LIMIT 10 OFFSET 2; END; } {LIMIT} } # EVIDENCE-OF: R-59581-44104 If SQLite is built with the # SQLITE_ENABLE_UPDATE_DELETE_LIMIT compile-time option then the syntax # of the UPDATE statement is extended with optional ORDER BY and LIMIT # clauses # # EVIDENCE-OF: R-45169-39597 -- syntax diagram update-stmt-limited # do_update_tests e_update-3.0 { 1 "UPDATE t1 SET a=b LIMIT 5" {} 2 "UPDATE t1 SET a=b LIMIT 5-1 OFFSET 2+2" {} 3 "UPDATE t1 SET a=b LIMIT 2+2, 16/4" {} 4 "UPDATE t1 SET a=b ORDER BY a LIMIT 5" {} 5 "UPDATE t1 SET a=b ORDER BY a LIMIT 5-1 OFFSET 2+2" {} 6 "UPDATE t1 SET a=b ORDER BY a LIMIT 2+2, 16/4" {} 7 "UPDATE t1 SET a=b WHERE a>2 LIMIT 5" {} 8 "UPDATE t1 SET a=b WHERE a>2 LIMIT 5-1 OFFSET 2+2" {} 9 "UPDATE t1 SET a=b WHERE a>2 LIMIT 2+2, 16/4" {} 10 "UPDATE t1 SET a=b WHERE a>2 ORDER BY a LIMIT 5" {} 11 "UPDATE t1 SET a=b WHERE a>2 ORDER BY a LIMIT 5-1 OFFSET 2+2" {} 12 "UPDATE t1 SET a=b WHERE a>2 ORDER BY a LIMIT 2+2, 16/4" {} } do_execsql_test e_update-3.1.0 { CREATE TABLE t7(q, r, s); INSERT INTO t7 VALUES(1, 'one', 'X'); INSERT INTO t7 VALUES(2, 'two', 'X'); INSERT INTO t7 VALUES(3, 'three', 'X'); INSERT INTO t7 VALUES(4, 'four', 'X'); INSERT INTO t7 VALUES(5, 'five', 'X'); INSERT INTO t7 VALUES(6, 'six', 'X'); INSERT INTO t7 VALUES(7, 'seven', 'X'); INSERT INTO t7 VALUES(8, 'eight', 'X'); INSERT INTO t7 VALUES(9, 'nine', 'X'); INSERT INTO t7 VALUES(10, 'ten', 'X'); } {} # EVIDENCE-OF: R-58862-44169 If an UPDATE statement has a LIMIT clause, # the maximum number of rows that will be updated is found by evaluating # the accompanying expression and casting it to an integer value. # do_update_tests e_update-3.1 -query { SELECT s FROM t7 } { 1 "UPDATE t7 SET s = q LIMIT 5" {1 2 3 4 5 X X X X X} 2 "UPDATE t7 SET s = r WHERE q>2 LIMIT 4" {1 2 three four five six X X X X} 3 "UPDATE t7 SET s = q LIMIT 0" {1 2 three four five six X X X X} } # EVIDENCE-OF: R-63582-45120 A negative value is interpreted as "no limit". # do_update_tests e_update-3.2 -query { SELECT s FROM t7 } { 1 "UPDATE t7 SET s = q LIMIT -1" {1 2 3 4 5 6 7 8 9 10} 2 "UPDATE t7 SET s = r WHERE q>4 LIMIT -1" {1 2 3 4 five six seven eight nine ten} 3 "UPDATE t7 SET s = 'X' LIMIT -1" {X X X X X X X X X X} } # EVIDENCE-OF: R-18628-11938 If the LIMIT expression evaluates to # non-negative value N and the UPDATE statement has an ORDER BY clause, # then all rows that would be updated in the absence of the LIMIT clause # are sorted according to the ORDER BY and the first N updated. # do_update_tests e_update-3.3 -query { SELECT s FROM t7 } { 1 "UPDATE t7 SET s = q ORDER BY r LIMIT 3" {X X X 4 5 X X 8 X X} 2 "UPDATE t7 SET s = r ORDER BY r DESC LIMIT 2" {X two three 4 5 X X 8 X X} 3 "UPDATE t7 SET s = q ORDER BY q DESC LIMIT 5" {X two three 4 5 6 7 8 9 10} X "UPDATE t7 SET s = 'X'" {X X X X X X X X X X} } # EVIDENCE-OF: R-30955-38324 If the UPDATE statement also has an OFFSET # clause, then it is similarly evaluated and cast to an integer value. # If the OFFSET expression evaluates to a non-negative value M, then the # first M rows are skipped and the following N rows updated instead. # do_update_tests e_update-3.3 -query { SELECT s FROM t7 } { 1 "UPDATE t7 SET s = q ORDER BY q LIMIT 3 OFFSET 2" {X X 3 4 5 X X X X X} 2 "UPDATE t7 SET s = q ORDER BY q DESC LIMIT 2, 3 " {X X 3 4 5 6 7 8 X X} X "UPDATE t7 SET s = 'X'" {X X X X X X X X X X} } # EVIDENCE-OF: R-19486-35828 If the UPDATE statement has no ORDER BY # clause, then all rows that would be updated in the absence of the # LIMIT clause are assembled in an arbitrary order before applying the # LIMIT and OFFSET clauses to determine which are actually updated. # # In practice, "arbitrary order" is rowid order. This is also tested # by e_update-3.2.* above. # do_update_tests e_update-3.4 -query { SELECT s FROM t7 } { 1 "UPDATE t7 SET s = q LIMIT 4, 2" {X X X X 5 6 X X X X} 2 "UPDATE t7 SET s = q LIMIT 2 OFFSET 7" {X X X X 5 6 X 8 9 X} } # EVIDENCE-OF: R-10927-26133 The ORDER BY clause on an UPDATE statement # is used only to determine which rows fall within the LIMIT. The order # in which rows are modified is arbitrary and is not influenced by the # ORDER BY clause. # do_execsql_test e_update-3.5.0 { CREATE TABLE t8(x); CREATE TRIGGER tr7 BEFORE UPDATE ON t7 BEGIN INSERT INTO t8 VALUES(old.q); END; } {} do_update_tests e_update-3.5 -query { SELECT x FROM t8 ; DELETE FROM t8 } { 1 "UPDATE t7 SET s = q ORDER BY r LIMIT -1" {1 2 3 4 5 6 7 8 9 10} 2 "UPDATE t7 SET s = q ORDER BY r ASC LIMIT -1" {1 2 3 4 5 6 7 8 9 10} 3 "UPDATE t7 SET s = q ORDER BY r DESC LIMIT -1" {1 2 3 4 5 6 7 8 9 10} 4 "UPDATE t7 SET s = q ORDER BY q DESC LIMIT 5" {6 7 8 9 10} } } ;# ifcapable update_delete_limit finish_test