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 used to generate VDBE code
** that implements the ALTER TABLE command.
**
** $Id: alter.c,v 1.13 2005/12/21 14:43:12 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.

  Table *pTab;              /* Table being altered */
  int iDb;                  /* Database number */
  const char *zDb;          /* Database name */
  const char *zTab;         /* Table name */
  char *zCol;               /* Null-terminated column definition */
  Column *pCol;             /* The new column */
  Expr *pDflt;              /* Default value for the new column */


  if( pParse->nErr ) return;
  pNew = pParse->pNewTable;
  assert( pNew );

  iDb = pNew->iDb;
  zDb = pParse->db->aDb[iDb].zName;

  ** the file format becomes 3.
  */
  sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);

  /* Reload the schema of the modified table. */
  reloadTableSchema(pParse, pTab, pTab->zName);
}


















/*
** This function is called by the parser after the table-name in
** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument 
** pSrc is the full-name of the table being altered.
**
** This routine makes a (partial) copy of the Table structure

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.360 2005/12/21 14:43:12 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.

  pIndex->nColumn = pList->nExpr;
  pIndex->onError = onError;
  pIndex->autoIndex = pName==0;
  pIndex->iDb = iDb;

  /* Check to see if we should honor DESC requests on index columns
  */
  if( pDb->file_format>=4 || (!pDb->descIndex && !db->init.busy) ){

    sortOrderMask = -1;   /* Honor DESC */



  }else{
    sortOrderMask = 0;    /* Ignore DESC */
  }

  /* Scan the names of the columns of the table to be indexed and
  ** load the column indices into the Index structure.  Report an error
  ** if any column is not found.

    Vdbe *v;
    char *zStmt;
    int iMem = pParse->nMem++;

    v = sqlite3GetVdbe(pParse);
    if( v==0 ) goto exit_create_index;






    /* Create the rootpage for the index
    */
    sqlite3BeginWriteOperation(pParse, 1, iDb);
    sqlite3VdbeAddOp(v, OP_CreateIndex, iDb, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);

    /* Make sure the file_format is at least 4 if we have DESC indices. */
    if( descSeen ){
      sqlite3MinimumFileFormat(pParse, iDb, 4);
    }

    /* Gather the complete text of the CREATE INDEX statement into
    ** the zStmt variable
    */
    if( pStart && pEnd ){
      /* A named index with an explicit CREATE INDEX statement */
      zStmt = sqlite3MPrintf("CREATE%s INDEX %.*s",

    freeIndex(pIndex);
  }
  sqlite3ExprListDelete(pList);
  sqlite3SrcListDelete(pTblName);
  sqliteFree(zName);
  return;
}

/*
** Generate code to make sure the file format number is at least minFormat.
** The generated code will increase the file format number if necessary.
*/
void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
  Vdbe *v;
  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp(v, OP_ReadCookie, iDb, 1);
    sqlite3VdbeAddOp(v, OP_Integer, minFormat, 0);
    sqlite3VdbeAddOp(v, OP_Ge, 0, sqlite3VdbeCurrentAddr(v)+3);
    sqlite3VdbeAddOp(v, OP_Integer, minFormat, 0);
    sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 1);
  }
}

/*
** Fill the Index.aiRowEst[] array with default information - information
** to be used when we have not run the ANALYZE command.
**
** aiRowEst[0] is suppose to contain the number of elements in the index.
** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.507 2005/12/21 14:43:12 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  sqlite3VdbeMemIntegerify(pTos);
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pTos->i);
  if( pOp->p2==0 ){
    /* When the schema cookie changes, record the new cookie internally */
    pDb->schema_cookie = pTos->i;
    db->flags |= SQLITE_InternChanges;
  }else if( pOp->p2==1 ){
    /* Record changes in the file format */
    pDb->file_format = pTos->i;
  }
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos--;
  break;
}

/* Opcode: VerifyCookie P1 P2 *

# 2005 December 21
#
# 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 regression tests for SQLite library.  The
# focus of this script is descending indices.
#
# $Id: descidx1.test,v 1.1 2005/12/21 14:43:12 drh Exp $
#

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

# This procedure sets the value of the file-format in file 'test.db'
# to $newval. Also, the schema cookie is incremented.
# 
proc set_file_format {newval} {
  set bt [btree_open test.db 10 0]
  btree_begin_transaction $bt
  set meta [btree_get_meta $bt]
  lset meta 2 $newval                    ;# File format
  lset meta 1 [expr [lindex $meta 1]+1]  ;# Schema cookie
  eval "btree_update_meta $bt $meta"
  btree_commit $bt
  btree_close $bt
}

# This procedure returns the value of the file-format in file 'test.db'.
# 
proc get_file_format {{fname test.db}} {
  set bt [btree_open $fname 10 0]
  set meta [btree_get_meta $bt]
  btree_close $bt
  lindex $meta 2
}

# Verify that the file format jumps to (at least) 4 as soon as a
# descending index is created.
#
do_test descidx1-1.1 {
  execsql {
    CREATE TABLE t1(a,b);
    CREATE INDEX i1 ON t1(b ASC);
  }
  get_file_format
} {1}
do_test descidx1-1.2 {
  execsql {
    CREATE INDEX i2 ON t1(a DESC);
  }
  get_file_format
} {4}

# Put some information in the table and verify that the descending
# index actually works.
#
do_test descidx1-2.1 {
  execsql {
    INSERT INTO t1 VALUES(1,1);
    INSERT INTO t1 VALUES(2,2);
    INSERT INTO t1 SELECT a+2, a+2 FROM t1;
    INSERT INTO t1 SELECT a+4, a+4 FROM t1;
    SELECT b FROM t1 WHERE a>3 AND a<7;
  }
} {6 5 4}
do_test descidx1-2.2 {
  execsql {
    SELECT a FROM t1 WHERE b>3 AND b<7;
  }
} {4 5 6}
do_test descidx1-2.3 {
  execsql {
    SELECT b FROM t1 WHERE a>=3 AND a<7;
  }
} {6 5 4 3}
do_test descidx1-2.4 {
  execsql {
    SELECT b FROM t1 WHERE a>3 AND a<=7;
  }
} {7 6 5 4}
do_test descidx1-2.5 {
  execsql {
    SELECT b FROM t1 WHERE a>=3 AND a<=7;
  }
} {7 6 5 4 3}
do_test descidx1-2.6 {
  execsql {
    SELECT a FROM t1 WHERE b>=3 AND b<=7;
  }
} {3 4 5 6 7}

# This procedure executes the SQL.  Then it checks to see if the OP_Sort
# opcode was executed.  If an OP_Sort did occur, then "sort" is appended
# to the result.  If no OP_Sort happened, then "nosort" is appended.
#
# This procedure is used to check to make sure sorting is or is not
# occurring as expected.
#
proc cksort {sql} {
  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x
  return $data
}

# Test sorting using a descending index.
#
do_test descidx1-3.1 {
  cksort {SELECT a FROM t1 ORDER BY a}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.2 {
  cksort {SELECT a FROM t1 ORDER BY a ASC}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.3 {
  cksort {SELECT a FROM t1 ORDER BY a DESC}
} {8 7 6 5 4 3 2 1 nosort}
do_test descidx1-3.4 {
  cksort {SELECT b FROM t1 ORDER BY a}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.5 {
  cksort {SELECT b FROM t1 ORDER BY a ASC}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.6 {
  cksort {SELECT b FROM t1 ORDER BY a DESC}
} {8 7 6 5 4 3 2 1 nosort}
do_test descidx1-3.7 {
  cksort {SELECT a FROM t1 ORDER BY b}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.8 {
  cksort {SELECT a FROM t1 ORDER BY b ASC}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.9 {
  cksort {SELECT a FROM t1 ORDER BY b DESC}
} {8 7 6 5 4 3 2 1 nosort}
do_test descidx1-3.10 {
  cksort {SELECT b FROM t1 ORDER BY b}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.11 {
  cksort {SELECT b FROM t1 ORDER BY b ASC}
} {1 2 3 4 5 6 7 8 nosort}
do_test descidx1-3.12 {
  cksort {SELECT b FROM t1 ORDER BY b DESC}
} {8 7 6 5 4 3 2 1 nosort}

do_test descidx1-3.21 {
  cksort {SELECT a FROM t1 WHERE a>3 AND a<8 ORDER BY a}
} {4 5 6 7 nosort}
do_test descidx1-3.22 {
  cksort {SELECT a FROM t1 WHERE a>3 AND a<8 ORDER BY a ASC}
} {4 5 6 7 nosort}
do_test descidx1-3.23 {
  cksort {SELECT a FROM t1 WHERE a>3 AND a<8 ORDER BY a DESC}
} {7 6 5 4 nosort}
do_test descidx1-3.24 {
  cksort {SELECT b FROM t1 WHERE a>3 AND a<8 ORDER BY a}
} {4 5 6 7 nosort}
do_test descidx1-3.25 {
  cksort {SELECT b FROM t1 WHERE a>3 AND a<8 ORDER BY a ASC}
} {4 5 6 7 nosort}
do_test descidx1-3.26 {
  cksort {SELECT b FROM t1 WHERE a>3 AND a<8 ORDER BY a DESC}
} {7 6 5 4 nosort}

finish_test