int i;
  u8 *pAlloc;
  char **azCol = 0;
  u8 *abPK;

  assert( pazCol && pabPK );

  nThis = strlen(zThis);
  zPragma = sqlite3_mprintf("PRAGMA '%q'.table_info('%q')", zDb, zThis);
  if( !zPragma ) return SQLITE_NOMEM;

  rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0);
  sqlite3_free(zPragma);
  if( rc!=SQLITE_OK ) return rc;

................................................................................
  int op,                         /* SQLITE_UPDATE, DELETE or INSERT */
  char const *zDb,                /* Database name */
  char const *zName,              /* Table name */
  sqlite3_int64 iKey1,            /* Rowid of row about to be deleted/updated */
  sqlite3_int64 iKey2             /* New rowid value (for a rowid UPDATE) */
){
  sqlite3_session *pSession;
  int nDb = strlen(zDb);
  int nName = strlen(zDb);

  assert( sqlite3_mutex_held(db->mutex) );

  for(pSession=(sqlite3_session *)pCtx; pSession; pSession=pSession->pNext){
    SessionTable *pTab;

    /* If this session is attached to a different database ("main", "temp" 
................................................................................
int sqlite3session_create(
  sqlite3 *db,                    /* Database handle */
  const char *zDb,                /* Name of db (e.g. "main") */
  sqlite3_session **ppSession     /* OUT: New session object */
){
  sqlite3_session *pNew;          /* Newly allocated session object */
  sqlite3_session *pOld;          /* Session object already attached to db */
  int nDb = strlen(zDb);          /* Length of zDb in bytes */

  /* Zero the output value in case an error occurs. */
  *ppSession = 0;

  /* Allocate and populate the new session object. */
  pNew = (sqlite3_session *)sqlite3_malloc(sizeof(sqlite3_session) + nDb + 1);
  if( !pNew ) return SQLITE_NOMEM;
................................................................................
      SessionChange *p;
      SessionChange *pNext;
      for(p=pTab->apChange[i]; p; p=pNext){
        pNext = p->pNext;
        sqlite3_free(p);
      }
    }
    sqlite3_free(pTab->azCol);
    sqlite3_free(pTab->apChange);
    sqlite3_free(pTab);
  }

  /* Free the session object itself. */
  sqlite3_free(pSession);
}
................................................................................
    pSession->bAutoAttach = 1;
  }else{
    SessionTable *pTab;           /* New table object (if required) */
    int nName;                    /* Number of bytes in string zName */

    /* First search for an existing entry. If one is found, this call is
    ** a no-op. Return early. */
    nName = strlen(zName);
    for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){
      if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break;
    }

    if( !pTab ){
      /* Allocate new SessionTable object. */
      pTab = (SessionTable *)sqlite3_malloc(sizeof(SessionTable) + nName + 1);
................................................................................
/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 
** called. Otherwise, append a single varint to the buffer. 
**
** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
** returning.
*/
static void sessionAppendVarint(SessionBuffer *p, sqlite3_int64 v, int *pRc){
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, 9, pRc) ){
    p->nBuf += sessionVarintPut(&p->aBuf[p->nBuf], v);
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 
................................................................................
** returning.
*/
static void sessionAppendStr(
  SessionBuffer *p, 
  const char *zStr, 
  int *pRc
){
  int nStr = strlen(zStr);
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, nStr, pRc) ){
    memcpy(&p->aBuf[p->nBuf], zStr, nStr);
    p->nBuf += nStr;
  }
}

/*
................................................................................
** returning.
*/
static void sessionAppendIdent(
  SessionBuffer *p,               /* Buffer to a append to */
  const char *zStr,               /* String to quote, escape and append */
  int *pRc                        /* IN/OUT: Error code */
){
  int nStr = strlen(zStr)*2 + 2 + 1;
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, nStr, pRc) ){
    char *zOut = (char *)&p->aBuf[p->nBuf];
    const char *zIn = zStr;
    *zOut++ = '"';
    while( *zIn ){
      if( *zIn=='"' ) *zOut++ = '"';
      *zOut++ = *(zIn++);
    }
    *zOut++ = '"';
    p->nBuf = ((u8 *)zOut - p->aBuf);
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is
** called. Otherwse, it appends the serialized version of the value stored
** in column iCol of the row that SQL statement pStmt currently points
................................................................................
        rc = SQLITE_SCHEMA;
      }

      /* Write a table header */
      sessionAppendByte(&buf, 'T', &rc);
      sessionAppendVarint(&buf, nCol, &rc);
      sessionAppendBlob(&buf, pTab->abPK, nCol, &rc);
      sessionAppendBlob(&buf, (u8 *)zName, strlen(zName)+1, &rc);

      /* Build and compile a statement to execute: */
      if( rc==SQLITE_OK ){
        rc = sessionSelectStmt(
            db, pSession->zDb, zName, nCol, azCol, abPK, &pSel);
      }

................................................................................
        }
      }

      sqlite3_finalize(pSel);
      if( buf.nBuf==nNoop ){
        buf.nBuf = nRewind;
      }
      sqlite3_free(azCol);
    }
  }

  if( rc==SQLITE_OK ){
    *pnChangeset = buf.nBuf;
    *ppChangeset = buf.aBuf;
  }else{
................................................................................
  c = *(aChange++);
  if( c=='T' ){
    int nByte;                    /* Bytes to allocate for apValue */
    aChange += sessionVarintGet(aChange, &p->nCol);
    p->abPK = (u8 *)aChange;
    aChange += p->nCol;
    p->zTab = (char *)aChange;
    aChange += (strlen((char *)aChange) + 1);
    p->op = *(aChange++);
    p->bIndirect = *(aChange++);
    sqlite3_free(p->apValue);
    nByte = sizeof(sqlite3_value *) * p->nCol * 2;
    p->apValue = (sqlite3_value **)sqlite3_malloc(nByte);
    if( !p->apValue ){
      return (p->rc = SQLITE_NOMEM);
................................................................................
        **   * A constant 'T' character,
        **   * Number of columns in said table (a varint),
        **   * An array of nCol bytes (abPK),
        **   * A nul-terminated table name.
        */
        int nByte = 1 + sessionVarintGet(&aIn[i+1], &nCol);
        nByte += nCol;
        nByte += 1 + strlen((char *)&aIn[i+nByte]);
        memcpy(&aOut[i], &aIn[i], nByte);
        i += nByte;
        break;
      }

      case SQLITE_INSERT:
      case SQLITE_DELETE: {
        int nByte;
        u8 *aEnd = &aIn[i+2];

        sessionReadRecord(&aEnd, nCol, 0);
        aOut[i] = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
        aOut[i+1] = aIn[i+1];
        nByte = aEnd - &aIn[i+2];
        memcpy(&aOut[i+2], &aIn[i+2], nByte);
        i += 2 + nByte;
        break;
      }

      case SQLITE_UPDATE: {
        int nByte1;              /* Size of old.* record in bytes */
        int nByte2;              /* Size of new.* record in bytes */
        u8 *aEnd = &aIn[i+2];    

        sessionReadRecord(&aEnd, nCol, 0);
        nByte1 = aEnd - &aIn[i+2];
        sessionReadRecord(&aEnd, nCol, 0);
        nByte2 = aEnd - &aIn[i+2] - nByte1;

        aOut[i] = SQLITE_UPDATE;
        aOut[i+1] = aIn[i+1];
        memcpy(&aOut[i+2], &aIn[i+2+nByte1], nByte2);
        memcpy(&aOut[i+2+nByte2], &aIn[i+2], nByte1);

        i += 2 + nByte1 + nByte2;
................................................................................
  ),
  void *pCtx                      /* First argument passed to xConflict */
){
  int schemaMismatch = 0;
  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */  
  int rc;                         /* Return code */
  const char *zTab = 0;           /* Name of current table */
  int nTab = 0;                   /* Result of strlen(zTab) */
  SessionApplyCtx sApply;         /* changeset_apply() context object */

  memset(&sApply, 0, sizeof(sApply));
  rc = sqlite3changeset_start(&pIter, nChangeset, pChangeset);
  if( rc!=SQLITE_OK ) return rc;

  sqlite3_mutex_enter(sqlite3_db_mutex(db));
................................................................................
    
    sqlite3changeset_op(pIter, &zNew, &nCol, &op, 0);

    if( zTab==0 || sqlite3_strnicmp(zNew, zTab, nTab+1) ){
      u8 *abPK;

      schemaMismatch = 0;
      sqlite3_free(sApply.azCol);
      sqlite3_finalize(sApply.pDelete);
      sqlite3_finalize(sApply.pUpdate); 
      sqlite3_finalize(sApply.pInsert);
      sqlite3_finalize(sApply.pSelect);
      memset(&sApply, 0, sizeof(sApply));
      sApply.db = db;

................................................................................
          (rc = sessionSelectRow(db, zTab, &sApply))
       || (rc = sessionUpdateRow(db, zTab, &sApply))
       || (rc = sessionDeleteRow(db, zTab, &sApply))
       || (rc = sessionInsertRow(db, zTab, &sApply))
      ){
        break;
      }
      nTab = strlen(zTab);
    }

    /* If there is a schema mismatch on the current table, proceed to the
    ** next change. A log message has already been issued. */
    if( schemaMismatch ) continue;

    rc = sessionApplyOneOp(pIter, &sApply, xConflict, pCtx, &bReplace, &bRetry);
................................................................................
    sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
  }

  sqlite3_finalize(sApply.pInsert);
  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);
  sqlite3_finalize(sApply.pSelect);
  sqlite3_free(sApply.azCol);
  sqlite3_mutex_leave(sqlite3_db_mutex(db));
  return rc;
}

#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */

  int i;
  u8 *pAlloc;
  char **azCol = 0;
  u8 *abPK;

  assert( pazCol && pabPK );

  nThis = sqlite3Strlen30(zThis);
  zPragma = sqlite3_mprintf("PRAGMA '%q'.table_info('%q')", zDb, zThis);
  if( !zPragma ) return SQLITE_NOMEM;

  rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0);
  sqlite3_free(zPragma);
  if( rc!=SQLITE_OK ) return rc;

................................................................................
  int op,                         /* SQLITE_UPDATE, DELETE or INSERT */
  char const *zDb,                /* Database name */
  char const *zName,              /* Table name */
  sqlite3_int64 iKey1,            /* Rowid of row about to be deleted/updated */
  sqlite3_int64 iKey2             /* New rowid value (for a rowid UPDATE) */
){
  sqlite3_session *pSession;
  int nDb = sqlite3Strlen30(zDb);
  int nName = sqlite3Strlen30(zName);

  assert( sqlite3_mutex_held(db->mutex) );

  for(pSession=(sqlite3_session *)pCtx; pSession; pSession=pSession->pNext){
    SessionTable *pTab;

    /* If this session is attached to a different database ("main", "temp" 
................................................................................
int sqlite3session_create(
  sqlite3 *db,                    /* Database handle */
  const char *zDb,                /* Name of db (e.g. "main") */
  sqlite3_session **ppSession     /* OUT: New session object */
){
  sqlite3_session *pNew;          /* Newly allocated session object */
  sqlite3_session *pOld;          /* Session object already attached to db */
  int nDb = sqlite3Strlen30(zDb); /* Length of zDb in bytes */

  /* Zero the output value in case an error occurs. */
  *ppSession = 0;

  /* Allocate and populate the new session object. */
  pNew = (sqlite3_session *)sqlite3_malloc(sizeof(sqlite3_session) + nDb + 1);
  if( !pNew ) return SQLITE_NOMEM;
................................................................................
      SessionChange *p;
      SessionChange *pNext;
      for(p=pTab->apChange[i]; p; p=pNext){
        pNext = p->pNext;
        sqlite3_free(p);
      }
    }
    sqlite3_free((char*)pTab->azCol);  /* cast works around VC++ bug */
    sqlite3_free(pTab->apChange);
    sqlite3_free(pTab);
  }

  /* Free the session object itself. */
  sqlite3_free(pSession);
}
................................................................................
    pSession->bAutoAttach = 1;
  }else{
    SessionTable *pTab;           /* New table object (if required) */
    int nName;                    /* Number of bytes in string zName */

    /* First search for an existing entry. If one is found, this call is
    ** a no-op. Return early. */
    nName = sqlite3Strlen30(zName);
    for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){
      if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break;
    }

    if( !pTab ){
      /* Allocate new SessionTable object. */
      pTab = (SessionTable *)sqlite3_malloc(sizeof(SessionTable) + nName + 1);
................................................................................
/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 
** called. Otherwise, append a single varint to the buffer. 
**
** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
** returning.
*/
static void sessionAppendVarint(SessionBuffer *p, int v, int *pRc){
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, 9, pRc) ){
    p->nBuf += sessionVarintPut(&p->aBuf[p->nBuf], v);
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 
................................................................................
** returning.
*/
static void sessionAppendStr(
  SessionBuffer *p, 
  const char *zStr, 
  int *pRc
){
  int nStr = sqlite3Strlen30(zStr);
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, nStr, pRc) ){
    memcpy(&p->aBuf[p->nBuf], zStr, nStr);
    p->nBuf += nStr;
  }
}

/*
................................................................................
** returning.
*/
static void sessionAppendIdent(
  SessionBuffer *p,               /* Buffer to a append to */
  const char *zStr,               /* String to quote, escape and append */
  int *pRc                        /* IN/OUT: Error code */
){
  int nStr = sqlite3Strlen30(zStr)*2 + 2 + 1;
  if( *pRc==SQLITE_OK && 0==sessionBufferGrow(p, nStr, pRc) ){
    char *zOut = (char *)&p->aBuf[p->nBuf];
    const char *zIn = zStr;
    *zOut++ = '"';
    while( *zIn ){
      if( *zIn=='"' ) *zOut++ = '"';
      *zOut++ = *(zIn++);
    }
    *zOut++ = '"';
    p->nBuf = (int)((u8 *)zOut - p->aBuf);
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is
** called. Otherwse, it appends the serialized version of the value stored
** in column iCol of the row that SQL statement pStmt currently points
................................................................................
        rc = SQLITE_SCHEMA;
      }

      /* Write a table header */
      sessionAppendByte(&buf, 'T', &rc);
      sessionAppendVarint(&buf, nCol, &rc);
      sessionAppendBlob(&buf, pTab->abPK, nCol, &rc);
      sessionAppendBlob(&buf, (u8 *)zName, sqlite3Strlen30(zName)+1, &rc);

      /* Build and compile a statement to execute: */
      if( rc==SQLITE_OK ){
        rc = sessionSelectStmt(
            db, pSession->zDb, zName, nCol, azCol, abPK, &pSel);
      }

................................................................................
        }
      }

      sqlite3_finalize(pSel);
      if( buf.nBuf==nNoop ){
        buf.nBuf = nRewind;
      }
      sqlite3_free((char*)azCol);  /* cast works around VC++ bug */
    }
  }

  if( rc==SQLITE_OK ){
    *pnChangeset = buf.nBuf;
    *ppChangeset = buf.aBuf;
  }else{
................................................................................
  c = *(aChange++);
  if( c=='T' ){
    int nByte;                    /* Bytes to allocate for apValue */
    aChange += sessionVarintGet(aChange, &p->nCol);
    p->abPK = (u8 *)aChange;
    aChange += p->nCol;
    p->zTab = (char *)aChange;
    aChange += (sqlite3Strlen30((char *)aChange) + 1);
    p->op = *(aChange++);
    p->bIndirect = *(aChange++);
    sqlite3_free(p->apValue);
    nByte = sizeof(sqlite3_value *) * p->nCol * 2;
    p->apValue = (sqlite3_value **)sqlite3_malloc(nByte);
    if( !p->apValue ){
      return (p->rc = SQLITE_NOMEM);
................................................................................
        **   * A constant 'T' character,
        **   * Number of columns in said table (a varint),
        **   * An array of nCol bytes (abPK),
        **   * A nul-terminated table name.
        */
        int nByte = 1 + sessionVarintGet(&aIn[i+1], &nCol);
        nByte += nCol;
        nByte += 1 + sqlite3Strlen30((char *)&aIn[i+nByte]);
        memcpy(&aOut[i], &aIn[i], nByte);
        i += nByte;
        break;
      }

      case SQLITE_INSERT:
      case SQLITE_DELETE: {
        int nByte;
        u8 *aEnd = &aIn[i+2];

        sessionReadRecord(&aEnd, nCol, 0);
        aOut[i] = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
        aOut[i+1] = aIn[i+1];
        nByte = (int)(aEnd - &aIn[i+2]);
        memcpy(&aOut[i+2], &aIn[i+2], nByte);
        i += 2 + nByte;
        break;
      }

      case SQLITE_UPDATE: {
        int nByte1;              /* Size of old.* record in bytes */
        int nByte2;              /* Size of new.* record in bytes */
        u8 *aEnd = &aIn[i+2];    

        sessionReadRecord(&aEnd, nCol, 0);
        nByte1 = (int)(aEnd - &aIn[i+2]);
        sessionReadRecord(&aEnd, nCol, 0);
        nByte2 = (int)(aEnd - &aIn[i+2]) - nByte1;

        aOut[i] = SQLITE_UPDATE;
        aOut[i+1] = aIn[i+1];
        memcpy(&aOut[i+2], &aIn[i+2+nByte1], nByte2);
        memcpy(&aOut[i+2+nByte2], &aIn[i+2], nByte1);

        i += 2 + nByte1 + nByte2;
................................................................................
  ),
  void *pCtx                      /* First argument passed to xConflict */
){
  int schemaMismatch = 0;
  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */  
  int rc;                         /* Return code */
  const char *zTab = 0;           /* Name of current table */
  int nTab = 0;                   /* Result of sqlite3Strlen30(zTab) */
  SessionApplyCtx sApply;         /* changeset_apply() context object */

  memset(&sApply, 0, sizeof(sApply));
  rc = sqlite3changeset_start(&pIter, nChangeset, pChangeset);
  if( rc!=SQLITE_OK ) return rc;

  sqlite3_mutex_enter(sqlite3_db_mutex(db));
................................................................................
    
    sqlite3changeset_op(pIter, &zNew, &nCol, &op, 0);

    if( zTab==0 || sqlite3_strnicmp(zNew, zTab, nTab+1) ){
      u8 *abPK;

      schemaMismatch = 0;
      sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
      sqlite3_finalize(sApply.pDelete);
      sqlite3_finalize(sApply.pUpdate); 
      sqlite3_finalize(sApply.pInsert);
      sqlite3_finalize(sApply.pSelect);
      memset(&sApply, 0, sizeof(sApply));
      sApply.db = db;

................................................................................
          (rc = sessionSelectRow(db, zTab, &sApply))
       || (rc = sessionUpdateRow(db, zTab, &sApply))
       || (rc = sessionDeleteRow(db, zTab, &sApply))
       || (rc = sessionInsertRow(db, zTab, &sApply))
      ){
        break;
      }
      nTab = sqlite3Strlen30(zTab);
    }

    /* If there is a schema mismatch on the current table, proceed to the
    ** next change. A log message has already been issued. */
    if( schemaMismatch ) continue;

    rc = sessionApplyOneOp(pIter, &sApply, xConflict, pCtx, &bReplace, &bRetry);
................................................................................
    sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
  }

  sqlite3_finalize(sApply.pInsert);
  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);
  sqlite3_finalize(sApply.pSelect);
  sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
  sqlite3_mutex_leave(sqlite3_db_mutex(db));
  return rc;
}

#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */

                      db->aLimit[SQLITE_LIMIT_LENGTH]);
  out.db = db;
  if( db->vdbeExecCnt>1 ){
    while( *zRawSql ){
      const char *zStart = zRawSql;
      while( *(zRawSql++)!='\n' && *zRawSql );
      sqlite3StrAccumAppend(&out, "-- ", 3);
      sqlite3StrAccumAppend(&out, zStart, zRawSql-zStart);
    }
  }else{
    while( zRawSql[0] ){
      n = findNextHostParameter(zRawSql, &nToken);
      assert( n>0 );
      sqlite3StrAccumAppend(&out, zRawSql, n);
      zRawSql += n;

                      db->aLimit[SQLITE_LIMIT_LENGTH]);
  out.db = db;
  if( db->vdbeExecCnt>1 ){
    while( *zRawSql ){
      const char *zStart = zRawSql;
      while( *(zRawSql++)!='\n' && *zRawSql );
      sqlite3StrAccumAppend(&out, "-- ", 3);
      sqlite3StrAccumAppend(&out, zStart, (int)(zRawSql-zStart));
    }
  }else{
    while( zRawSql[0] ){
      n = findNextHostParameter(zRawSql, &nToken);
      assert( n>0 );
      sqlite3StrAccumAppend(&out, zRawSql, n);
      zRawSql += n;