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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Disable the LIKE optimization if the column on the left-hand-side of the LIKE operator belongs to a virtual table.
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SHA1: 0bacb879e18026f2a8e22fe3e4bc8d27de5c4416
User & Date: dan 2012-03-29 14:29:07
Context
2012-03-29
15:11
Merge fts4-incr-merge with trunk. check-in: 4d6de3e9 user: dan tags: trunk
14:29
Disable the LIKE optimization if the column on the left-hand-side of the LIKE operator belongs to a virtual table. check-in: 0bacb879 user: dan tags: trunk
07:51
Fix an out of date comment on sqlite3ArrayAllocate(). check-in: 4afdd5ae user: dan tags: trunk
Changes
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Changes to src/where.c.

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    return 0;
  }
#ifdef SQLITE_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;

  if( pLeft->op!=TK_COLUMN || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT ){


    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;







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    return 0;
  }
#ifdef SQLITE_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;
  if( pLeft->op!=TK_COLUMN 
   || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT 
   || IsVirtual(pLeft->pTab)
  ){
    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;

Changes to test/vtab1.test.

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# This file implements regression tests for SQLite library.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.57 2008/08/01 17:51:47 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl


ifcapable !vtab||!schema_pragmas {
  finish_test
  return
}

#----------------------------------------------------------------------
................................................................................
# in that file for the special behaviour of the Tcl $echo_module variable.
#
# TODO: 
#   * How to test the sqlite3_index_constraint_usage.omit field?
#   * vtab1-5.*
#
# vtab1-14.*: Test 'IN' constraints - i.e. "SELECT * FROM t1 WHERE id IN(...)"



#


#----------------------------------------------------------------------
# Test cases vtab1.1.*
#

................................................................................
      DROP TABLE e5;
      SAVEPOINT one;
      ROLLBACK TO one;
    COMMIT;
  }
} {}








unset -nocomplain echo_module_begin_fail













































finish_test







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# This file implements regression tests for SQLite library.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.57 2008/08/01 17:51:47 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix vtab1

ifcapable !vtab||!schema_pragmas {
  finish_test
  return
}

#----------------------------------------------------------------------
................................................................................
# in that file for the special behaviour of the Tcl $echo_module variable.
#
# TODO: 
#   * How to test the sqlite3_index_constraint_usage.omit field?
#   * vtab1-5.*
#
# vtab1-14.*: Test 'IN' constraints - i.e. "SELECT * FROM t1 WHERE id IN(...)"
#
# vtab1-18.*: Check that the LIKE optimization is not applied when the lhs
#             is a virtual table column.
#


#----------------------------------------------------------------------
# Test cases vtab1.1.*
#

................................................................................
      DROP TABLE e5;
      SAVEPOINT one;
      ROLLBACK TO one;
    COMMIT;
  }
} {}

#-------------------------------------------------------------------------
# The following tests - vtab1-18.* - test that the optimization of LIKE
# constraints in where.c plays well with virtual tables.
#
#   18.1.*: Case-insensitive LIKE.
#   18.2.*: Case-sensitive LIKE.
#
unset -nocomplain echo_module_begin_fail

do_execsql_test 18.1.0 {
  CREATE TABLE t6(a, b TEXT);
  CREATE INDEX i6 ON t6(b, a);
  INSERT INTO t6 VALUES(1, 'Peter');
  INSERT INTO t6 VALUES(2, 'Andrew');
  INSERT INTO t6 VALUES(3, 'James');
  INSERT INTO t6 VALUES(4, 'John');
  INSERT INTO t6 VALUES(5, 'Phillip');
  INSERT INTO t6 VALUES(6, 'Bartholomew');
  CREATE VIRTUAL TABLE e6 USING echo(t6);
}

foreach {tn sql res filter} {
  1.1 "SELECT a FROM e6 WHERE b>'James'" {4 1 5}
    {xFilter {SELECT rowid, * FROM 't6' WHERE b > ?} James}

  1.2 "SELECT a FROM e6 WHERE b>='J' AND b<'K'" {3 4}
    {xFilter {SELECT rowid, * FROM 't6' WHERE b >= ? AND b < ?} J K}

  1.3 "SELECT a FROM e6 WHERE b LIKE 'J%'" {3 4}
    {xFilter {SELECT rowid, * FROM 't6'}}

  1.4 "SELECT a FROM e6 WHERE b LIKE 'j%'" {3 4}
    {xFilter {SELECT rowid, * FROM 't6'}}
} {
  set echo_module {}
  do_execsql_test 18.$tn.1 $sql $res
  do_test         18.$tn.2 { lrange $::echo_module 2 end } $filter
}

do_execsql_test 18.2.0 {  PRAGMA case_sensitive_like = ON }
foreach {tn sql res filter} {
  2.1 "SELECT a FROM e6 WHERE b LIKE 'J%'" {3 4}
    {xFilter {SELECT rowid, * FROM 't6'}}

  2.2 "SELECT a FROM e6 WHERE b LIKE 'j%'" {}
    {xFilter {SELECT rowid, * FROM 't6'}}
} {
  set echo_module {}
  do_execsql_test 18.$tn.1 $sql $res
  do_test         18.$tn.2 { lrange $::echo_module 2 end } $filter
}
do_execsql_test 18.2.x {  PRAGMA case_sensitive_like = OFF }

finish_test