SQLite

  pNew->nRef = 1;
  pNew->nCol = pTab->nCol;
  assert( pNew->nCol>0 );
  nAlloc = (((pNew->nCol-1)/8)*8)+8;
  assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
  pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
  pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
  sqlite3MemLink(pNew, pNew->zName);
  if( !pNew->aCol || !pNew->zName ){
    db->mallocFailed = 1;
    goto exit_begin_add_column;
  }
  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
  for(i=0; i<pNew->nCol; i++){
    Column *pCol = &pNew->aCol[i];

    }
    pIndex->aiRowEst[i] = v;
    if( *z==' ' ) z++;
  }
  return 0;
}























/*
** Load the content of the sqlite_stat1 and sqlite_stat2 tables. The
** contents of sqlite_stat1 are used to populate the Index.aiRowEst[]
** arrays. The contents of sqlite_stat2 are used to populate the
** Index.aSample[] arrays.
**
** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR

  assert( db->aDb[iDb].pBt!=0 );
  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

  /* Clear any prior statistics */
  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
    Index *pIdx = sqliteHashData(i);
    sqlite3DefaultRowEst(pIdx);
    if( pIdx->aSample ){
      sqlite3MemUnlink(pIdx, pIdx->aSample);
      sqlite3DbFree(db, pIdx->aSample);
      pIdx->aSample = 0;
    }
  }

  /* Check to make sure the sqlite_stat1 table exists */
  sInfo.db = db;
  sInfo.zDatabase = db->aDb[iDb].zName;
  if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
    return SQLITE_ERROR;

      while( sqlite3_step(pStmt)==SQLITE_ROW ){
        char *zIndex = (char *)sqlite3_column_text(pStmt, 0);
        Index *pIdx = sqlite3FindIndex(db, zIndex, sInfo.zDatabase);
        if( pIdx ){
          int iSample = sqlite3_column_int(pStmt, 1);
          if( iSample<SQLITE_INDEX_SAMPLES && iSample>=0 ){
            int eType = sqlite3_column_type(pStmt, 2);
            IndexSample *aSample = pIdx->aSample;

            if( aSample==0 ){
              static const int sz = sizeof(IndexSample)*SQLITE_INDEX_SAMPLES;
              pIdx->aSample = aSample = sqlite3DbMallocZeroChild(0, sz, pIdx);
              if( aSample==0 ){
                db->mallocFailed = 1;
                break;
              }

            }
  
            assert( aSample );
            {
              IndexSample *pSample = &aSample[iSample];
              pSample->eType = (u8)eType;
              if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
                pSample->u.r = sqlite3_column_double(pStmt, 2);
              }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
                const char *z = (const char *)(
                    (eType==SQLITE_BLOB) ?
                    sqlite3_column_blob(pStmt, 2):
                    sqlite3_column_text(pStmt, 2)
                );
                int n = sqlite3_column_bytes(pStmt, 2);
                if( n>24 ){
                  n = 24;
                }
                pSample->nByte = (u8)n;
                if( n < 1){
                  pSample->u.z = 0;
                }else{
                  char *zSample;
                  pSample->u.z = zSample = sqlite3DbMallocRawChild(0,n,aSample);
                  if( zSample ){
                    memcpy(zSample, z, n);
                  }else{
                    db->mallocFailed = 1;
                    break;
                  }
                }
              }
            }

  return p;
}

/*
** Reclaim the memory used by an index
*/
static void freeIndex(sqlite3 *db, Index *p){



  sqlite3DbFree(db, p);
}

/*
** Remove the given index from the index hash table, and free
** its memory structures.
**

  int i;
  Column *pCol;
  assert( pTable!=0 );
  if( (pCol = pTable->aCol)!=0 ){
    for(i=0; i<pTable->nCol; i++, pCol++){
      sqlite3DbFree(db, pCol->zName);
      sqlite3ExprDelete(db, pCol->pDflt);



    }
    sqlite3DbFree(db, pTable->aCol);
  }
  pTable->aCol = 0;
  pTable->nCol = 0;
}

  /* Delete any foreign keys attached to this table. */
  sqlite3FkDelete(db, pTable);

  /* Delete the Table structure itself.
  */
  sqliteResetColumnNames(db, pTable);

  sqlite3SelectDelete(db, pTable->pSelect);
#ifndef SQLITE_OMIT_CHECK
  sqlite3ExprDelete(db, pTable->pCheck);
#endif
  sqlite3VtabClear(db, pTable);
  sqlite3DbFree(db, pTable);
}

  if( pTable==0 ){
    db->mallocFailed = 1;
    pParse->rc = SQLITE_NOMEM;
    pParse->nErr++;
    goto begin_table_error;
  }
  pTable->zName = zName;
  sqlite3MemLink(pTable, zName);
  pTable->iPKey = -1;
  pTable->pSchema = db->aDb[iDb].pSchema;
  pTable->nRef = 1;
  assert( pParse->pNewTable==0 );
  pParse->pNewTable = pTable;

  /* If this is the magic sqlite_sequence table used by autoincrement,

      sqlite3ErrorMsg(pParse, "duplicate column name: %s", z);
      sqlite3DbFree(db, z);
      return;
    }
  }
  if( (p->nCol & 0x7)==0 ){
    Column *aNew;
    aNew = sqlite3DbRealloc(db, p->aCol, (p->nCol+8)*sizeof(p->aCol[0]));
    if( aNew==0 ){
      sqlite3DbFree(db, z);
      return;
    }
    p->aCol = aNew;
  }
  pCol = &p->aCol[p->nCol];

  Column *pCol;

  p = pParse->pNewTable;
  if( p==0 || NEVER(p->nCol<1) ) return;
  pCol = &p->aCol[p->nCol-1];
  assert( pCol->zType==0 );
  pCol->zType = sqlite3NameFromToken(pParse->db, pType);
  sqlite3MemLink(p->aCol, pCol->zType);
  pCol->affinity = sqlite3AffinityType(pCol->zType);
}

/*
** The expression is the default value for the most recently added column
** of the table currently under construction.
**

    }else{
      /* A copy of pExpr is used instead of the original, as pExpr contains
      ** tokens that point to volatile memory. The 'span' of the expression
      ** is required by pragma table_info.
      */
      sqlite3ExprDelete(db, pCol->pDflt);
      pCol->pDflt = sqlite3ExprDup(db, pSpan->pExpr, EXPRDUP_REDUCE);

      pCol->zDflt = sqlite3DbStrNDup(db, (char*)pSpan->zStart,
                                     (int)(pSpan->zEnd - pSpan->zStart));
      sqlite3MemLink(p->aCol, pCol->zDflt);
    }
  }
  sqlite3ExprDelete(db, pSpan->pExpr);
}

/*
** Designate the PRIMARY KEY for the table.  pList is a list of names 

  db = pParse->db;
  zColl = sqlite3NameFromToken(db, pToken);
  if( !zColl ) return;

  if( sqlite3LocateCollSeq(pParse, zColl) ){
    Index *pIdx;
    p->aCol[i].zColl = zColl;
    sqlite3MemLink(p->aCol, zColl);
  
    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
    ** then an index may have been created on this column before the
    ** collation type was added. Correct this if it is the case.
    */
    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn==1 );

    ** The column affinity string will eventually be deleted by
    ** sqliteDeleteIndex() when the Index structure itself is cleaned
    ** up.
    */
    int n;
    Table *pTab = pIdx->pTable;
    sqlite3 *db = sqlite3VdbeDb(v);
    pIdx->zColAff = (char *)sqlite3DbMallocRawChild(0, pIdx->nColumn+2, pIdx);
    if( !pIdx->zColAff ){
      db->mallocFailed = 1;
      return 0;
    }

    for(n=0; n<pIdx->nColumn; n++){
      pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
    }
    pIdx->zColAff[n++] = SQLITE_AFF_NONE;
    pIdx->zColAff[n] = 0;
  }
 

  ** sqlite3DeleteTable() when the Table structure itself is cleaned up.
  */
  if( !pTab->zColAff ){
    char *zColAff;
    int i;
    sqlite3 *db = sqlite3VdbeDb(v);

    zColAff = (char *)sqlite3DbMallocRawChild(0, pTab->nCol+1, pTab);
    if( !zColAff ){
      db->mallocFailed = 1;
      return;
    }

    for(i=0; i<pTab->nCol; i++){
      zColAff[i] = pTab->aCol[i].affinity;
    }
    zColAff[pTab->nCol] = '\0';

    pTab->zColAff = zColAff;
  }

  if( p ){
    memset(p, 0, n);
  }
  return p;
}

/*
** Allocate and zero memory.  If the allocation fails, set
** the mallocFailed flag in the connection pointer.
*/
void *sqlite3DbMallocZero(sqlite3 *db, int n){
  void *p = sqlite3DbMallocRaw(db, n);
  if( p ){
    memset(p, 0, n);
  }
  return p;
}

/*
** Allocate and zero memory child memory.  If the allocation fails, set
** the mallocFailed flag in the connection pointer.
*/
void *sqlite3DbMallocZeroChild(sqlite3 *db, int n, void *pParent){
  void *p = sqlite3DbMallocRaw(db, n);
  if( p ){
    memset(p, 0, n);
    sqlite3MemLink(pParent, p);
  }
  return p;
}



/*
** Allocate and zero memory.  If the allocation fails, make
** the mallocFailed flag in the connection pointer.
**
** If db!=0 and db->mallocFailed is true (indicating a prior malloc
** failure on the same database connection) then always return 0.

            ((db && db->lookaside.bEnabled) ? MEMTYPE_DB : MEMTYPE_HEAP));

finish_emalloc_raw:
  memset(p, 0, sizeof(EMemHdr));
  setValidEMem(p);
  return (void*)&p[1];
}

/*
** A convenience wrapper around sqlite3DbMallocRaw() and sqlite3MemLink().
*/
void *sqlite3DbMallocRawChild(sqlite3 *db, int n, void *pParent){
  void *p = sqlite3DbMallocRaw(db, n);
  sqlite3MemLink(pParent, p);
  return p;
}

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
**
** The pOld memory block must not be linked into an allocation hierarchy
** as a child.  It is OK for the allocation to be the root of a hierarchy

  if( db->mallocFailed ) return;
  memset(&sNC, 0, sizeof(sNC));
  sNC.pSrcList = pSelect->pSrc;
  a = pSelect->pEList->a;
  for(i=0, pCol=aCol; i<nCol; i++, pCol++){
    p = a[i].pExpr;
    pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
    sqlite3MemLink(aCol, pCol->zType);
    pCol->affinity = sqlite3ExprAffinity(p);
    if( pCol->affinity==0 ) pCol->affinity = SQLITE_AFF_NONE;
    pColl = sqlite3ExprCollSeq(pParse, p);
    if( pColl ){
      pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
      sqlite3MemLink(aCol, pCol->zColl);
    }
  }
}

/*
** Given a SELECT statement, generate a Table structure that describes
** the result set of that SELECT.

      assert( pSel!=0 );
      assert( pFrom->pTab==0 );
      sqlite3WalkSelect(pWalker, pSel);
      pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
      if( pTab==0 ) return WRC_Abort;
      pTab->nRef = 1;
      pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
      sqlite3MemLink(pTab, pTab->zName);
      while( pSel->pPrior ){ pSel = pSel->pPrior; }
      selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
      pTab->iPKey = -1;
      pTab->tabFlags |= TF_Ephemeral;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */

int sqlite3MallocInit(void);
void sqlite3MallocEnd(void);
void *sqlite3Malloc(int);
void *sqlite3MallocZero(int);
void *sqlite3DbMallocZero(sqlite3*, int);
void *sqlite3DbMallocRaw(sqlite3*, int);
void *sqlite3DbMallocZeroChild(sqlite3*, int, void *pParent);
void *sqlite3DbMallocRawChild(sqlite3*, int, void *pParent);
char *sqlite3DbStrDup(sqlite3*,const char*);
char *sqlite3DbStrNDup(sqlite3*,const char*, int);
void *sqlite3Realloc(void*, int);
void *sqlite3DbReallocOrFree(sqlite3 *, void *, int);
void *sqlite3DbRealloc(sqlite3 *, void *, int);
void sqlite3DbFree(sqlite3*, void*);
void sqlite3MemLink(void *pParent, void *pChild);

CollSeq *sqlite3GetCollSeq(sqlite3*, u8, CollSeq *, const char*);
char sqlite3AffinityType(const char*);
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);
int sqlite3FindDb(sqlite3*, Token*);
int sqlite3FindDbName(sqlite3 *, const char *);
int sqlite3AnalysisLoad(sqlite3*,int iDB);

void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);