SQLite

    for(j=i+1; j<k; j++){
      if( apNew[j]->pgno<(unsigned)minV ){
        minI = j;
        minV = apNew[j]->pgno;
      }
    }
    if( minI>i ){
      int t;
      MemPage *pT;
      t = apNew[i]->pgno;
      pT = apNew[i];
      apNew[i] = apNew[minI];
      apNew[minI] = pT;
    }
  }
  TRACE(("new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
    apNew[0]->pgno, szNew[0],

void sqlite3FkCheck(
  Parse *pParse,                  /* Parse context */
  Table *pTab,                    /* Row is being deleted from this table */ 
  int regOld,                     /* Previous row data is stored here */
  int regNew                      /* New row data is stored here */
){
  sqlite3 *db = pParse->db;       /* Database handle */
  Vdbe *v;                        /* VM to write code to */
  FKey *pFKey;                    /* Used to iterate through FKs */
  int iDb;                        /* Index of database containing pTab */
  const char *zDb;                /* Name of database containing pTab */
  int isIgnoreErrors = pParse->disableTriggers;

  /* Exactly one of regOld and regNew should be non-zero. */
  assert( (regOld==0)!=(regNew==0) );

  /* If foreign-keys are disabled, this function is a no-op. */
  if( (db->flags&SQLITE_ForeignKeys)==0 ) return;

  v = sqlite3GetVdbe(pParse);
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;

  /* Loop through all the foreign key constraints for which pTab is the
  ** child table (the table that the foreign key definition is part of).  */
  for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
    Table *pTo;                   /* Parent table of foreign key pFKey */

  /* Register allocations */
  int regFromSelect = 0;/* Base register for data coming from SELECT */
  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
  int regRowCount = 0;  /* Memory cell used for the row counter */
  int regIns;           /* Block of regs holding rowid+data being inserted */
  int regRowid;         /* registers holding insert rowid */
  int regData;          /* register holding first column to insert */
  int regRecord;        /* Holds the assemblied row record */
  int regEof = 0;       /* Register recording end of SELECT data */
  int *aRegIdx = 0;     /* One register allocated to each index */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  Trigger *pTrigger;          /* List of triggers on pTab, if required */
  int tmask;                  /* Mask of trigger times */

    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
    addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRecord = ++pParse->nMem;
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
  if( IsVirtual(pTab) ){
    regRowid++;
    pParse->nMem++;
  }
  regData = regRowid+1;

        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Abort:
        sqlite3MayAbort(pParse);
      case OE_Rollback:
      case OE_Fail: {
        char *zMsg;
        j1 = sqlite3VdbeAddOp3(v, OP_HaltIfNull,
                                  SQLITE_CONSTRAINT, onError, regData+i);
        zMsg = sqlite3MPrintf(pParse->db, "%s.%s may not be NULL",
                              pTab->zName, pTab->aCol[i].zName);
        sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
        break;
      }
      case OE_Ignore: {

  int size;
  Table *pTab;
  Db *pDb;
  char const *azArg[4];
  int meta[5];
  InitData initData;
  char const *zMasterSchema;
  char const *zMasterName = SCHEMA_TABLE(iDb);
  int openedTransaction = 0;

  /*
  ** The master database table has a structure like this
  */
  static const char master_schema[] = 
     "CREATE TABLE sqlite_master(\n"

  Trigger *pTrig = pParse->pNewTrigger;   /* Trigger being finished */
  char *zName;                            /* Name of trigger */
  sqlite3 *db = pParse->db;               /* The database */
  DbFixer sFix;                           /* Fixer object */
  int iDb;                                /* Database containing the trigger */
  Token nameToken;                        /* Trigger name for error reporting */

  pTrig = pParse->pNewTrigger;
  pParse->pNewTrigger = 0;
  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
  zName = pTrig->zName;
  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
  pTrig->step_list = pStepList;
  while( pStepList ){
    pStepList->pTrig = pTrig;

  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid;       /* The old rowid */
  int regNewRowid;       /* The new rowid */
  int regNew;
  int regOld = 0;
  int regRowSet = 0;     /* Rowset of rows to be updated */
  int regRec;            /* Register used for new table record to insert */

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto update_cleanup;
  }
  assert( pTabList->nSrc==1 );

    pParse->nMem += pTab->nCol;
  }
  if( chngRowid || pTrigger || hasFK ){
    regNewRowid = ++pParse->nMem;
  }
  regNew = pParse->nMem + 1;
  pParse->nMem += pTab->nCol;
  regRec = ++pParse->nMem;

  /* Start the view context. */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* If we are trying to update a view, realize that view into

  ** Each type field is a varint representing the serial type of the 
  ** corresponding data element (see sqlite3VdbeSerialType()). The
  ** hdr-size field is also a varint which is the offset from the beginning
  ** of the record to data0.
  */
  nData = 0;         /* Number of bytes of data space */
  nHdr = 0;          /* Number of bytes of header space */
  nByte = 0;         /* Data space required for this record */
  nZero = 0;         /* Number of zero bytes at the end of the record */
  nField = pOp->p1;
  zAffinity = pOp->p4.z;
  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=p->nMem+1 );
  pData0 = &aMem[nField];
  nField = pOp->p2;
  pLast = &pData0[nField-1];

    **
    ** The second algorithm is to select a rowid at random and see if
    ** it already exists in the table.  If it does not exist, we have
    ** succeeded.  If the random rowid does exist, we select a new one
    ** and try again, up to 100 times.
    */
    assert( pC->isTable );
    cnt = 0;

#ifdef SQLITE_32BIT_ROWID
#   define MAX_ROWID 0x7fffffff
#else
    /* Some compilers complain about constants of the form 0x7fffffffffffffff.
    ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
    ** to provide the constant while making all compilers happy.

** Check to see if column iCol of the given statement is valid.  If
** it is, return a pointer to the Mem for the value of that column.
** If iCol is not valid, return a pointer to a Mem which has a value
** of NULL.
*/
static Mem *columnMem(sqlite3_stmt *pStmt, int i){
  Vdbe *pVm;
  int vals;
  Mem *pOut;

  pVm = (Vdbe *)pStmt;
  if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
    sqlite3_mutex_enter(pVm->db->mutex);
    vals = sqlite3_data_count(pStmt);
    pOut = &pVm->pResultSet[i];
  }else{
    /* If the value passed as the second argument is out of range, return
    ** a pointer to the following static Mem object which contains the
    ** value SQL NULL. Even though the Mem structure contains an element
    ** of type i64, on certain architecture (x86) with certain compiler
    ** switches (-Os), gcc may align this Mem object on a 4-byte boundary

  /* Allocate the iterator */
  rc = walIteratorInit(pWal, &pIter);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pIter );

  mxPage = pWal->hdr.nPage;
  if( eMode!=SQLITE_CHECKPOINT_PASSIVE ) xBusy = xBusyCall;

  /* Compute in mxSafeFrame the index of the last frame of the WAL that is
  ** safe to write into the database.  Frames beyond mxSafeFrame might
  ** overwrite database pages that are in use by active readers and thus
  ** cannot be backfilled from the WAL.
  */

    **
    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    WhereTerm *pFinal;     /* Final subterm within the OR-clause. */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */

    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regRowset = 0;                        /* Register for RowSet object */
    int regRowid = 0;                         /* Register holding rowid */
    int iLoopBody = sqlite3VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;
   
    pTerm = pLevel->plan.u.pTerm;
    assert( pTerm!=0 );
    assert( pTerm->eOperator==WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pFinal = &pOrWc->a[pOrWc->nTerm-1];
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList ni pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
    */

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
  ** the use of indices become tests that are evaluated against each row of
  ** the relevant input tables.
  */
  k = 0;
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
    testcase( pTerm->wtFlags & TERM_CODED );
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->prereqAll & notReady)!=0 ){
      testcase( pWInfo->untestedTerms==0
               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
      pWInfo->untestedTerms = 1;
      continue;
    }
    pE = pTerm->pExpr;
    assert( pE!=0 );
    if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
      continue;
    }
    sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
    k = 1;
    pTerm->wtFlags |= TERM_CODED;
  }

  /* For a LEFT OUTER JOIN, generate code that will record the fact that
  ** at least one row of the right table has matched the left table.  
  */
  if( pLevel->iLeftJoin ){

  **   pWInfo->a[].iIdxCur   The VDBE cursor for the index
  **   pWInfo->a[].pTerm     When wsFlags==WO_OR, the OR-clause term
  **
  ** This loop also figures out the nesting order of tables in the FROM
  ** clause.
  */
  notReady = ~(Bitmask)0;
  pTabItem = pTabList->a;
  pLevel = pWInfo->a;
  andFlags = ~0;
  WHERETRACE(("*** Optimizer Start ***\n"));
  for(i=iFrom=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
    WhereCost bestPlan;         /* Most efficient plan seen so far */
    Index *pIdx;                /* Index for FROM table at pTabItem */
    int j;                      /* For looping over FROM tables */
    int bestJ = -1;             /* The value of j */