SQLite

      zCol = pIter->azTblCol[iCid];
      zType = pIter->azTblType[iCid];
    }

    zRet = sqlite3_mprintf("%z%s\"%w\" COLLATE %Q", zRet, zCom, zCol, zCollate);
    if( pIter->bUnique==0 || sqlite3_column_int(pXInfo, 5) ){
      const char *zOrder = (bDesc ? " DESC" : "");
      zImpPK = sqlite3_mprintf("%z%s\"ota_imp_%d%w\"%s", 
          zImpPK, zCom, nBind, zCol, zOrder
      );
    }
    zImpCols = sqlite3_mprintf("%z%s\"ota_imp_%d%w\" %s COLLATE %Q", 
        zImpCols, zCom, nBind, zCol, zType, zCollate
    );
    zWhere = sqlite3_mprintf(
        "%z%s\"ota_imp_%d%w\" IS ?", zWhere, zAnd, nBind, zCol
    );
    if( zRet==0 || zImpPK==0 || zImpCols==0 || zWhere==0 ) rc = SQLITE_NOMEM;
    zCom = ", ";
    zAnd = " AND ";
    nBind++;
  }

  rc2 = sqlite3_finalize(pXInfo);

    if( pIter->eType==OTA_PK_WITHOUT_ROWID ){
      char *zPk = otaWithoutRowidPK(p, pIter);
      if( zPk ){
        zSql = otaMPrintf(p, "%z, %z", zSql, zPk);
      }
    }

    zSql = otaMPrintf(p, "CREATE TABLE \"ota_imp_%w\"(%z)%s", 
        pIter->zTbl, zSql, 
        (pIter->eType==OTA_PK_WITHOUT_ROWID ? " WITHOUT ROWID" : "")
    );
    if( p->rc==SQLITE_OK ){
      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->db, "main", 1, tnum);
      p->rc = sqlite3_exec(p->db, zSql, 0, 0, &p->zErrmsg);
      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->db, "main", 0, 0);
    }
    sqlite3_free(zSql);

    if( nOffset ){
      zLimit = sqlite3_mprintf(" LIMIT -1 OFFSET %d", nOffset);
      if( !zLimit ) p->rc = SQLITE_NOMEM;
    }

    if( zIdx ){
      const char *zTbl = pIter->zTbl;
      char *zImposterCols = 0;    /* Columns for imposter table */
      char *zImposterPK = 0;      /* Primary key declaration for imposter */
      char *zWhere = 0;           /* WHERE clause on PK columns */
      char *zBind = 0;
      int nBind = 0;

      assert( pIter->eType!=OTA_PK_VTAB );
      zCollist = otaObjIterGetIndexCols(
          p, pIter, &zImposterCols, &zImposterPK, &zWhere, &nBind
      );
      zBind = otaObjIterGetBindlist(p, nBind);

      /* Create the imposter table used to write to this index. */
      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->db, "main", 0, 1);
      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->db, "main", 1, tnum);
      otaMPrintfExec(p, 
          "CREATE TABLE \"ota_imp_%w\"( %s, PRIMARY KEY( %s ) ) WITHOUT ROWID",
          zTbl, zImposterCols, zImposterPK
      );
      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->db, "main", 0, 0);

      /* Create the statement to insert index entries */
      pIter->nCol = nBind;
      if( p->rc==SQLITE_OK ){
        p->rc = prepareFreeAndCollectError(p->db, &pIter->pInsert, &p->zErrmsg,
          sqlite3_mprintf("INSERT INTO \"ota_imp_%w\" VALUES(%s)", zTbl, zBind)
        );
      }

      /* And to delete index entries */
      if( p->rc==SQLITE_OK ){
        p->rc = prepareFreeAndCollectError(p->db, &pIter->pDelete, &p->zErrmsg,
          sqlite3_mprintf("DELETE FROM \"ota_imp_%w\" WHERE %s", zTbl, zWhere)
        );
      }

      /* Create the SELECT statement to read keys in sorted order */
      if( p->rc==SQLITE_OK ){
        char *zSql;
        if( pIter->eType==OTA_PK_EXTERNAL || pIter->eType==OTA_PK_NONE ){

            )
        );
      }

      /* Create the imposter table or tables (if required). */
      otaCreateImposterTable(p, pIter);
      otaCreateImposterTable2(p, pIter);
      zWrite = (pIter->eType==OTA_PK_VTAB ? "" : "ota_imp_");

      /* Create the INSERT statement to write to the target PK b-tree */
      if( p->rc==SQLITE_OK ){
        p->rc = prepareFreeAndCollectError(p->db, &pIter->pInsert, pz,
            sqlite3_mprintf(
              "INSERT INTO main.\"%s%w\"(%s%s) VALUES(%s)", 
              zWrite, zTbl, zCollist, (bOtaRowid ? ", _rowid_" : ""), zBindings
            )
        );
      }

      /* Create the DELETE statement to write to the target PK b-tree */
      if( p->rc==SQLITE_OK ){
        p->rc = prepareFreeAndCollectError(p->db, &pIter->pDelete, pz,
            sqlite3_mprintf(
              "DELETE FROM main.\"%s%w\" WHERE %s", zWrite, zTbl, zWhere
            )
        );
      }

      if( pIter->eType!=OTA_PK_VTAB ){
        const char *zOtaRowid = "";
        if( pIter->eType==OTA_PK_EXTERNAL || pIter->eType==OTA_PK_NONE ){
          zOtaRowid = ", ota_rowid";
        }

        /* Create the ota_tmp_xxx table and the triggers to populate it. */
        otaMPrintfExec(p, 

            "CREATE TABLE IF NOT EXISTS ota.'ota_tmp_%q' AS "
            "SELECT *%s FROM ota.'data_%q' WHERE 0;"

            "CREATE TEMP TRIGGER ota_delete_tr BEFORE DELETE ON \"%s%w\" "
            "BEGIN "
            "  INSERT INTO 'ota_tmp_%q'(ota_control, %s%s) VALUES(2, %s);"
            "END;"

            "CREATE TEMP TRIGGER ota_update1_tr BEFORE UPDATE ON \"%s%w\" "
            "BEGIN "
            "  INSERT INTO 'ota_tmp_%q'(ota_control, %s%s) VALUES(2, %s);"
            "END;"






            "CREATE TEMP TRIGGER ota_update2_tr AFTER UPDATE ON \"%s%w\" "
            "BEGIN "
            "  INSERT INTO 'ota_tmp_%q'(ota_control, %s%s) VALUES(3, %s);"
            "END;"
            , zTbl, (pIter->eType==OTA_PK_EXTERNAL ? ", 0 AS ota_rowid" : "")
            , zTbl, 
            zWrite, zTbl, zTbl, zCollist, zOtaRowid, zOldlist,
            zWrite, zTbl, zTbl, zCollist, zOtaRowid, zOldlist,
            zWrite, zTbl, zTbl, zCollist, zOtaRowid, zNewlist
        );
        if( pIter->eType==OTA_PK_EXTERNAL || pIter->eType==OTA_PK_NONE ){
          otaMPrintfExec(p, 
              "CREATE TEMP TRIGGER ota_insert_tr AFTER INSERT ON \"%s%w\" "
              "BEGIN "
              "  INSERT INTO 'ota_tmp_%q'(ota_control, %s, ota_rowid)"
              "  VALUES(0, %s);"
              "END;",
              zWrite, zTbl, zTbl, zCollist, zNewlist
          );
        }


      }

      /* Allocate space required for the zMask field. */
      if( p->rc==SQLITE_OK ){
        int nMask = pIter->nTblCol+1;
        pIter->zMask = (char*)sqlite3_malloc(nMask);
        if( pIter->zMask==0 ){

  }else{
    char *zWhere = otaObjIterGetWhere(p, pIter);
    char *zSet = otaObjIterGetSetlist(p, pIter, zMask);
    char *zUpdate = 0;
    sqlite3_finalize(pIter->pUpdate);
    pIter->pUpdate = 0;
    if( p->rc==SQLITE_OK ){
      const char *zPrefix = "";

      if( pIter->eType!=OTA_PK_VTAB ) zPrefix = "ota_imp_";
      zUpdate = sqlite3_mprintf("UPDATE \"%s%w\" SET %s WHERE %s", 

          zPrefix, pIter->zTbl, zSet, zWhere
      );
      p->rc = prepareFreeAndCollectError(
          p->db, &pIter->pUpdate, &p->zErrmsg, zUpdate
      );
      *ppStmt = pIter->pUpdate;
    }
    if( p->rc==SQLITE_OK ){

    assert( p->rc!=SQLITE_OK || p->eStage!=0 );

    if( p->rc==SQLITE_OK ){
      if( p->eStage==OTA_STAGE_OAL ){
        const char *zScript =
          "PRAGMA journal_mode=off;"
          "PRAGMA pager_ota_mode=1;"

          "BEGIN IMMEDIATE;"
        ;
        p->rc = sqlite3_exec(p->db, zScript, 0, 0, &p->zErrmsg);
  
        /* Point the object iterator at the first object */
        if( p->rc==SQLITE_OK ){
          p->rc = otaObjIterFirst(p, &p->objiter);

/*
** Return the database handle used by pOta.
*/
sqlite3 *sqlite3ota_db(sqlite3ota *pOta){
  return (pOta ? pOta->db : 0);
}


/*
** If the error code currently stored in the OTA handle is SQLITE_CONSTRAINT,
** then edit any error message string so as to remove all occurrences of
** the pattern "ota_imp_[0-9]*".
*/
static void otaEditErrmsg(sqlite3ota *p){
  if( p->rc==SQLITE_CONSTRAINT && p->zErrmsg ){
    int i;
    int nErrmsg = strlen(p->zErrmsg);
    for(i=0; i<(nErrmsg-8); i++){
      if( memcmp(&p->zErrmsg[i], "ota_imp_", 8)==0 ){
        int nDel = 8;
        while( p->zErrmsg[i+nDel]>='0' && p->zErrmsg[i+nDel]<='9' ) nDel++;
        memmove(&p->zErrmsg[i], &p->zErrmsg[i+nDel], nErrmsg + 1 - i - nDel);
        nErrmsg -= nDel;
      }
    }
  }
}

/*
** Close the OTA handle.
*/
int sqlite3ota_close(sqlite3ota *p, char **pzErrmsg){
  int rc;
  if( p ){

      p->rc = sqlite3_exec(p->db, "PRAGMA pager_ota_mode=2", 0, 0, &p->zErrmsg);
    }

    /* Close the open database handle */
    if( p->pCkpt ) sqlite3_ckpt_close(p->pCkpt, 0, 0);
    sqlite3_close(p->db);

    otaEditErrmsg(p);
    rc = p->rc;
    *pzErrmsg = p->zErrmsg;
    sqlite3_free(p);
  }else{
    rc = SQLITE_NOMEM;
    *pzErrmsg = 0;
  }