SQLite

    }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
      zErrDyn = sqlite3MPrintf(db, 
        "attached databases must use the same text encoding as main database");
      rc = SQLITE_ERROR;
    }
    pPager = sqlite3BtreePager(aNew->pBt);
    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
    /* journal_mode set by the OP_JournalMode opcode that will following
    ** the OP_Function opcode that invoked this function. */
    sqlite3BtreeSecureDelete(aNew->pBt,
                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
  }
  aNew->safety_level = 3;
  aNew->zName = sqlite3DbStrDup(db, zName);
  if( rc==SQLITE_OK && aNew->zName==0 ){
    rc = SQLITE_NOMEM;

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp3(v, OP_Function, 0, regArgs+3-pFunc->nArg, regArgs+3);
    assert( pFunc->nArg==-1 || (pFunc->nArg&0xff)==pFunc->nArg );
    sqlite3VdbeChangeP5(v, (u8)(pFunc->nArg));
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

    if( type==SQLITE_ATTACH ){
      /* On an attach, also set the journal mode.  Note that
      ** sqlite3VdbeUsesBtree() is not call here since the iDb index
      ** will be out of range prior to the new database being attached.
      ** The OP_JournalMode opcode will all sqlite3VdbeUsesBtree() for us.
      */
      sqlite3VdbeAddOp3(v, OP_JournalMode, db->nDb, regArgs+3, 
                           db->dfltJournalMode);
    }

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).
    */
    sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH));
  }

    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "locking_mode", SQLITE_STATIC);
    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, zRet, 0);
    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
  }else

  /*
  **  PRAGMA [database.]journal_mode
  **  PRAGMA [database.]journal_mode =
  **                      (delete|persist|off|truncate|memory|wal|off)
  */
  if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
    int eMode;                    /* One of the PAGER_JOURNALMODE_XXX symbols */

    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", SQLITE_STATIC);

      */
      eMode = db->dfltJournalMode;
      sqlite3VdbeAddOp2(v, OP_String8, 0, 1);
      sqlite3VdbeChangeP4(v, -1, sqlite3JournalModename(eMode), P4_STATIC);
    }else{
      int ii;

      if( pId2->n==0 ){
        /* When there is no database name before the "journal_mode" keyword
        ** in the PRAGMA, then the journal-mode will be set on
        ** all attached databases, as well as the main db file.
        **
        ** Also, the sqlite3.dfltJournalMode variable is set so that
        ** any subsequently attached databases also use the specified
        ** journal mode.

        */
        db->dfltJournalMode = (u8)eMode;
      }

      for(ii=db->nDb-1; ii>=0; ii--){
        if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
          sqlite3VdbeUsesBtree(v, ii);

       || eNew==PAGER_JOURNALMODE_PERSIST 
       || eNew==PAGER_JOURNALMODE_OFF
       || eNew==PAGER_JOURNALMODE_MEMORY
       || eNew==PAGER_JOURNALMODE_WAL
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );

  /* This opcode is used in two places: PRAGMA journal_mode and ATTACH.
  ** In PRAGMA journal_mode, the sqlite3VdbeUsesBtree() routine is called
  ** when the statment is prepared and so p->aMutex.nMutex>0.  All mutexes
  ** are already acquired.  But when used in ATTACH, sqlite3VdbeUsesBtree()
  ** is not called when the statement is prepared because it requires the
  ** iDb index of the database as a parameter, and the database has not
  ** yet been attached so that index is unavailable.  We have to wait
  ** until runtime (now) to get the mutex on the newly attached database.
  ** No other mutexes are required by the ATTACH command so this is safe
  ** to do.
  */
  assert( (p->btreeMask & (1<<pOp->p1))!=0 || p->aMutex.nMutex==0 );
  if( p->aMutex.nMutex==0 ){
    /* This occurs right after ATTACH.  Get a mutex on the newly ATTACHed
    ** database. */
    sqlite3VdbeUsesBtree(p, pOp->p1);
    sqlite3VdbeMutexArrayEnter(p);
  }

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);

#ifndef SQLITE_OMIT_WAL
  zFilename = sqlite3PagerFilename(pPager);
  pVfs = sqlite3PagerVfs(pPager);

  assert( zP4!=0 );
  return zP4;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
** The prepared statement has to know in advance which Btree objects
** will be used so that it can acquire mutexes on them all in sorted
** order (via sqlite3VdbeMutexArrayEnter().  Mutexes are acquired
** in order (and released in reverse order) to avoid deadlocks.
*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  int mask;
  assert( i>=0 && i<p->db->nDb && i<sizeof(u32)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  mask = ((u32)1)<<i;
  if( (p->btreeMask & mask)==0 ){