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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Artifact 412b42f8036b28d8b2f3534d89389ad946a4b1a65a12263f51936f7424296f1b:


# 2017 September 10
#
# 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.
#
#***********************************************************************
# Test the virtual table interface. In particular the xBestIndex
# method.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix bestindex4

ifcapable !vtab {
  finish_test
  return
}

#-------------------------------------------------------------------------
# Virtual table callback for a virtual table named $tbl.
#  
proc vtab_cmd {method args} {

  set binops(ne)    !=
  set binops(eq)    =
  set binops(isnot) "IS NOT"
  set binops(is)    "IS"

  set unops(isnotnull) "IS NOT NULL"
  set unops(isnull)    "IS NULL"

  set cols(0) a
  set cols(1) b
  set cols(2) c

  switch -- $method {
    xConnect {
      return "CREATE TABLE t1(a, b, c)"
    }

    xBestIndex {
      foreach {clist orderby mask} $args {}

      set cost 1000000.0
      set ret [list]
      set str [list]

      set v 0
      for {set i 0} {$i < [llength $clist]} {incr i} {
        array unset C
        array set C [lindex $clist $i]
        if {$C(usable)} {
          if {[info exists binops($C(op))]} {
            lappend ret omit $i
            lappend str "$cols($C(column)) $binops($C(op)) %$v%"
            incr v
            set cost [expr $cost / 2]
          }
          if {[info exists unops($C(op))]} {
            lappend ret omit $i
            lappend str "$cols($C(column)) $unops($C(op))"
            incr v
            set cost [expr $cost / 2]
          }
        }
      }

      lappend ret idxstr [join $str " AND "]
      lappend ret cost $cost
      return $ret
    }

    xFilter {
      set q [lindex $args 1]
      set a [lindex $args 2]
      for {set v 0} {$v < [llength $a]} {incr v} {
        set val [lindex $a $v]
        set q [string map [list %$v% '$val'] $q]
      }
      if {$q==""} { set q 1 }
      lappend ::xFilterQueries "WHERE $q"
      return [list sql "SELECT rowid, * FROM t1x WHERE $q"]
    }
  }
  return ""
}

proc vtab_simple {method args} {
  switch -- $method {
    xConnect {
      return "CREATE TABLE t2(x)"
    }
    xBestIndex {
      return [list cost 999999.0]
    }
    xFilter {
      return [list sql "SELECT rowid, * FROM t2x"]
    }
  }
  return ""
}

register_tcl_module db

proc do_vtab_query_test {tn query result} {
  set ::xFilterQueries [list]
  uplevel [list
    do_test $tn [string map [list %QUERY% $query] {
      set r [execsql {%QUERY%}]
      set r [concat $::xFilterQueries $r]
      set r
    }] [list {*}$result]
  ]
}

do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t1 USING tcl('vtab_cmd');
  CREATE TABLE t1x(a INTEGER, b TEXT, c REAL);
  INSERT INTO t1x VALUES(1, 2, 3);
  INSERT INTO t1x VALUES(4, 5, 6);
  INSERT INTO t1x VALUES(7, 8, 9);

  CREATE VIRTUAL TABLE t2 USING tcl('vtab_simple');
  CREATE TABLE t2x(x INTEGER);
  INSERT INTO t2x VALUES(1);
}

do_vtab_query_test 1.1 { SELECT * FROM t1 WHERE a!='hello'; } {
  "WHERE a != 'hello'"
  1 2 3.0 4 5 6.0 7 8 9.0
}

do_vtab_query_test 1.2.1 { SELECT * FROM t1 WHERE b!=8 } {
  "WHERE b != '8'"
  1 2 3.0 4 5 6.0
}
do_vtab_query_test 1.2.2 { SELECT * FROM t1 WHERE 8!=b } {
  "WHERE b != '8'"
  1 2 3.0 4 5 6.0
}

do_vtab_query_test 1.3 { SELECT * FROM t1 WHERE c IS NOT 3 } {
  "WHERE c IS NOT '3'"
  4 5 6.0 7 8 9.0
}
do_vtab_query_test 1.3.2 { SELECT * FROM t1 WHERE 3 IS NOT c } {
  "WHERE c IS NOT '3'"
  4 5 6.0 7 8 9.0
}

do_vtab_query_test 1.4.1 { SELECT * FROM t1, t2 WHERE x != a } {
  "WHERE a != '1'"
  4 5 6.0 1   7 8 9.0 1
}
do_vtab_query_test 1.4.2 { SELECT * FROM t1, t2 WHERE a != x } {
  "WHERE a != '1'"
  4 5 6.0 1   7 8 9.0 1
}

do_vtab_query_test 1.5.1 { SELECT * FROM t1 WHERE a IS NOT NULL } {
  "WHERE a IS NOT NULL"
  1 2 3.0 4 5 6.0 7 8 9.0
}
do_vtab_query_test 1.5.2 { SELECT * FROM t1 WHERE NULL IS NOT a } {
  "WHERE a IS NOT ''"
  1 2 3.0 4 5 6.0 7 8 9.0
}

do_vtab_query_test 1.6.1 { SELECT * FROM t1 WHERE a IS NULL } {
  "WHERE a IS NULL"
}

do_vtab_query_test 1.6.2 { SELECT * FROM t1 WHERE NULL IS a } {
  "WHERE a IS ''"
}

do_vtab_query_test 1.7.1 { SELECT * FROM t1 WHERE (a, b) IS (1, 2) } {
  "WHERE a IS '1' AND b IS '2'"
  1 2 3.0
}
do_vtab_query_test 1.7.2 { SELECT * FROM t1 WHERE (5, 4) IS (b, a) } {
  {WHERE b IS '5' AND a IS '4'} 
  4 5 6.0
}

#---------------------------------------------------------------------
do_execsql_test 2.0.0 {
  DELETE FROM t1x;
  INSERT INTO t1x VALUES('a', 'b', 'c');
}
do_execsql_test 2.0.1 { SELECT * FROM t1 } {a b c}
do_execsql_test 2.0.2 { SELECT * FROM t1 WHERE (a, b) != ('a', 'b'); } {}

do_execsql_test 2.1.0 {
  DELETE FROM t1x;
  INSERT INTO t1x VALUES(7, 8, 9);
}
do_execsql_test 2.1.1 { SELECT * FROM t1 } {7 8 9.0}
do_execsql_test 2.1.2 { SELECT * FROM t1 WHERE (a, b) != (7, '8') } {}
do_execsql_test 2.1.3 { SELECT * FROM t1 WHERE a!=7 OR b!='8' }
do_execsql_test 2.1.4 { SELECT * FROM t1 WHERE a!=7 OR b!='8' }


do_execsql_test 2.2.1 {
  CREATE TABLE t3(a INTEGER, b TEXT);
  INSERT INTO t3 VALUES(45, 46);
}
do_execsql_test 2.2.2 { SELECT * FROM t3 WHERE (a, b) != (45, 46); }
do_execsql_test 2.2.3 { SELECT * FROM t3 WHERE (a, b) != ('45', '46'); }
do_execsql_test 2.2.4 { SELECT * FROM t3 WHERE (a, b) == (45, 46); } {45 46}
do_execsql_test 2.2.5 { SELECT * FROM t3 WHERE (a, b) == ('45', '46'); } {45 46}

#---------------------------------------------------------------------
# Test the != operator on a virtual table with column affinities.
#
proc vtab_simple_integer {method args} {
  switch -- $method {
    xConnect {
      return "CREATE TABLE t4(x INTEGER)"
    }
    xBestIndex {
      return [list cost 999999.0]
    }
    xFilter {
      return [list sql "SELECT rowid, * FROM t4x"]
    }
  }
  return ""
}

do_execsql_test 3.0 {
  CREATE TABLE t4x(a INTEGER);
  INSERT INTO t4x VALUES(245);
  CREATE VIRTUAL TABLE t4 USING tcl('vtab_simple_integer');
}
do_execsql_test 3.1 { SELECT rowid, * FROM t4 WHERE x=245; } {1 245}
do_execsql_test 3.2 { SELECT rowid, * FROM t4 WHERE x='245'; } {1 245}
do_execsql_test 3.3 { SELECT rowid, * FROM t4 WHERE x!=245; } {}
do_execsql_test 3.4 { SELECT rowid, * FROM t4 WHERE x!='245'; } {}

do_execsql_test 3.5 { SELECT rowid, * FROM t4 WHERE rowid!=1 OR x!='245'; } {}


finish_test