SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.160 2004/03/02 18:37:41 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

static void generateSortTail(
  Select *p,       /* The SELECT statement */
  Vdbe *v,         /* Generate code into this VDBE */
  int nColumn,     /* Number of columns of data */
  int eDest,       /* Write the sorted results here */
  int iParm        /* Optional parameter associated with eDest */
){
  int end1 = sqliteVdbeMakeLabel(v);
  int end2 = sqliteVdbeMakeLabel(v);
  int addr;
  if( eDest==SRT_Sorter ) return;
  sqliteVdbeAddOp(v, OP_Sort, 0, 0);
  addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end1);
  if( p->iOffset>=0 ){
    sqliteVdbeAddOp(v, OP_MemIncr, p->iOffset, addr+4);
    sqliteVdbeAddOp(v, OP_Pop, 1, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, addr);
  }
  if( p->iLimit>=0 ){
    sqliteVdbeAddOp(v, OP_MemIncr, p->iLimit, end2);
  }
  switch( eDest ){
    case SRT_Callback: {
      sqliteVdbeAddOp(v, OP_SortCallback, nColumn, 0);
      break;
    }
    case SRT_Table:

      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
      break;
    }
    case SRT_Mem: {
      assert( nColumn==1 );
      sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
      sqliteVdbeAddOp(v, OP_Goto, 0, end1);
      break;
    }
    case SRT_Subroutine: {
      int i;
      for(i=0; i<nColumn; i++){
        sqliteVdbeAddOp(v, OP_Column, -1-i, i);
      }
      sqliteVdbeAddOp(v, OP_Gosub, 0, iParm);
      sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
  }
  sqliteVdbeAddOp(v, OP_Goto, 0, addr);
  sqliteVdbeResolveLabel(v, end2);
  sqliteVdbeAddOp(v, OP_Pop, 1, 0);
  sqliteVdbeResolveLabel(v, end1);
  sqliteVdbeAddOp(v, OP_SortReset, 0, 0);
}

/*
** Generate code that will tell the VDBE the datatypes of
** columns in the result set.
**

#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for miscellanous features that were
# left out of other test files.
#
# $Id: misc3.test,v 1.9 2004/03/02 18:37:42 drh Exp $

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

# Ticket #529.  Make sure an ABORT does not damage the in-memory cache
# that will be used by subsequent statements in the same transaction.
#

  execsql {EXPLAIN COMMIT}
  catchsql {COMMIT}
} {0 {}}
do_test misc3-6.3 {
  execsql {BEGIN; EXPLAIN ROLLBACK}
  catchsql {ROLLBACK}
} {0 {}}

# Ticket #640:  vdbe stack overflow with a LIMIT clause on a SELECT inside
# of a trigger.
#
do_test misc3-7.1 {
  execsql {
    BEGIN;
    CREATE TABLE y1(a);
    CREATE TABLE y2(b);
    CREATE TABLE y3(c);
    CREATE TRIGGER r1 AFTER DELETE ON y1 FOR EACH ROW BEGIN
      INSERT INTO y3(c) SELECT b FROM y2 ORDER BY b LIMIT 1;
    END;
    INSERT INTO y1 VALUES(1);
    INSERT INTO y1 VALUES(2);
    INSERT INTO y1 SELECT a+2 FROM y1;
    INSERT INTO y1 SELECT a+4 FROM y1;
    INSERT INTO y1 SELECT a+8 FROM y1;
    INSERT INTO y1 SELECT a+16 FROM y1;
    INSERT INTO y2 SELECT a FROM y1;
    COMMIT;
    SELECT count(*) FROM y1;
  }
} 32
do_test misc3-7.2 {
  execsql {
    DELETE FROM y1;
    SELECT count(*) FROM y1;
  }
} 0
do_test misc3-7.3 {
  execsql {
    SELECT count(*) FROM y3;
  }
} 32


finish_test