SQLite

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.450 2007/12/04 16:54:53 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.

  /* Generate code to remove the table from the master table
  ** on disk.
  */
  v = sqlite3GetVdbe(pParse);
  if( v ){
    Trigger *pTrigger;
    Db *pDb = &db->aDb[iDb];
    sqlite3BeginWriteOperation(pParse, 1, iDb);

#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      Vdbe *v = sqlite3GetVdbe(pParse);
      if( v ){
        sqlite3VdbeAddOp(v, OP_VBegin, 0, 0);
      }

    }
  }
#endif

  /* Generate code to remove the index and from the master table */
  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3BeginWriteOperation(pParse, 1, iDb);
    sqlite3NestedParse(pParse,
       "DELETE FROM %Q.%s WHERE name=%Q",
       db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
       pIndex->zName
    );
    sqlite3ChangeCookie(db, v, iDb);
    destroyRootPage(pParse, pIndex->tnum, iDb);

**
** 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 1.656 2007/12/04 16:54:53 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

** The statement is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Statement: {       /* no-push */
  int i = pOp->p1;
  Btree *pBt;
  if( i>=0 && i<db->nDb && (pBt = db->aDb[i].pBt)!=0
        && (db->autoCommit==0 || db->activeVdbeCnt>1) ){
    assert( sqlite3BtreeIsInTrans(pBt) );
    assert( (p->btreeMask & (1<<i))!=0 );
    if( !sqlite3BtreeIsInStmt(pBt) ){
      rc = sqlite3BtreeBeginStmt(pBt);
      p->openedStatement = 1;
    }
  }

    }
  }
#else
  iCnt = db->activeVdbeCnt;
#endif
  if( iCnt>1 ){
    rc = SQLITE_LOCKED;
    p->errorAction = OE_Abort;
  }else{
    assert( iCnt==1 );
    assert( (p->btreeMask & (1<<pOp->p2))!=0 );
    rc = sqlite3BtreeDropTable(db->aDb[pOp->p2].pBt, pOp->p1, &iMoved);
    pTos++;
    pTos->flags = MEM_Int;
    pTos->u.i = iMoved;

** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
**
** The integer *pMaxStack is set to the maximum number of vdbe stack
** entries that static analysis reveals this program might need.
**
** This routine also does the following optimization:  It scans for
** instructions that might cause a statement rollback.  Such instructions
** are:
**
**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
**   *  OP_Destroy
**   *  OP_VUpdate
**   *  OP_VRename
**
** If no such instruction is found, then every Statement instruction 
** is changed to a Noop.  In this way, we avoid creating the statement 
** journal file unnecessarily.
*/
static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs, int *pMaxStack){
  int i;
  int nMaxArgs = 0;
  int nMaxStack = p->nOp;
  Op *pOp;
  int *aLabel = p->aLabel;

    }
    if( opcode==OP_Halt ){
      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
        doesStatementRollback = 1;
      }
    }else if( opcode==OP_Statement ){
      hasStatementBegin = 1;
    }else if( opcode==OP_Destroy ){
      doesStatementRollback = 1;
#ifndef SQLITE_OMIT_VIRTUALTABLE
    }else if( opcode==OP_VUpdate || opcode==OP_VRename ){
      doesStatementRollback = 1;
    }else if( opcode==OP_VFilter ){
      int n;
      assert( p->nOp - i >= 3 );
      assert( pOp[-2].opcode==OP_Integer );

    /* Lock all btrees used by the statement */
    sqlite3BtreeMutexArrayEnter(&p->aMutex);

    /* Check for one of the special errors */
    mrc = p->rc & 0xff;
    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
    if( isSpecialError ){
      /* This loop does static analysis of the query to see which of the
      ** following three categories it falls into:
      **
      **     Read-only
      **     Query with statement journal
      **     Query without statement journal

# 2007 Dec 4
#
# 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 is to test that ticket #2820 has been fixed.
# Ticket #2820 observes that a DROP TABLE statement that
# occurs while a query is in process will fail with a
# "database is locked" error, but the entry in the sqlite_master
# table will still be removed.  This is incorrect.  The
# entry in the sqlite_master table should persist when 
# the DROP fails due to an error.
#
# $Id: tkt2820.test,v 1.1 2007/12/04 16:54:53 drh Exp $
#

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

proc test_schema_change {testid init ddl res} {
  db close
  file delete -force test.db test.db-journal
  sqlite3 db test.db
  execsql $init
  do_test tkt2820-$testid.1 {
    set STMT [sqlite3_prepare db {SELECT * FROM sqlite_master} -1 DUMMY]
    sqlite3_step $STMT
  } {SQLITE_ROW}
#if {$testid==3} {execsql {PRAGMA vdbe_trace=ON}}
  do_test tkt2820-$testid.2 "catchsql [list $ddl]" \
       {1 {database table is locked}}
  do_test tkt2820-$testid.3 {
    sqlite3_finalize $STMT
    execsql {SELECT name FROM sqlite_master ORDER BY 1}
  } $res
  integrity_check tkt2820-$testid.4
  db close
  sqlite3 db test.db
  integrity_check tkt2820-$testid.5
}

test_schema_change 1 {
  CREATE TABLE t1(a);
} {
  DROP TABLE t1
} {t1}
test_schema_change 2 {
  CREATE TABLE t1(a);
  CREATE TABLE t2(b);
} {
  DROP TABLE t2
} {t1 t2}
test_schema_change 3 {
  CREATE TABLE t1(a);
  CREATE INDEX i1 ON t1(a);
} {
  DROP INDEX i1
} {i1 t1}

# We further observe that prior to the fix associated with ticket #2820,
# no statement journal would be created on an SQL statement that was run
# while a second statement was active, as long as we are in autocommit
# mode.  This is incorrect.
#
do_test tkt2820-4.1 {
  db close
  file delete -force test.db test.db-journal
  sqlite3 db test.db
  db eval {
    CREATE TABLE t1(a INTEGER PRIMARY KEY);
    INSERT INTO t1 VALUES(1);
    INSERT INTO t1 VALUES(2);
  }

  # The INSERT statement within the loop should fail on a
  # constraint violation on the second inserted row.  This
  # should cause the entire INSERT to rollback using a statement
  # journal.
  #
  db eval {SELECT name FROM sqlite_master} {
    catch {db eval {
      INSERT INTO t1 SELECT a+1 FROM t1 ORDER BY a DESC
    }}
  }
  db eval {SELECT a FROM t1 ORDER BY a}
} {1 2}

finish_test

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library. The focus
# of this test is reading and writing to the database from within a
# virtual table xSync() callback.
#
# $Id: vtab7.test,v 1.4 2007/12/04 16:54:53 drh Exp $

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

ifcapable !vtab {
  finish_test
  return

  execsql {
    INSERT INTO abc2 VALUES(1, 2, 3);
    SELECT name FROM sqlite_master ORDER BY name;
  }
} {abc abc2 log newtab}

# Drop a database table from within xSync callback.
# This is not allowed.  Tables cannot be dropped while
# any other statement is active.
#
do_test vtab7-2.6 {
  set ::callbacks(xSync,abc) {
    set ::rc [catchsql { DROP TABLE newtab }]
  }
  execsql {
    INSERT INTO abc2 VALUES(1, 2, 3);
    SELECT name FROM sqlite_master ORDER BY name;
  }
} {abc abc2 log newtab}
do_test vtab7-2.6.1 {
  set ::rc
} {1 {database table is locked}}
execsql {DROP TABLE newtab}

# Write to an attached database from xSync().
ifcapable attach {
  do_test vtab7-3.1 {
    file delete -force test2.db
    file delete -force test2.db-journal
    execsql {

  set ::error
} {1 {database table is locked}}

trace remove variable ::echo_module write echo_module_trace
unset -nocomplain ::callbacks

finish_test