SQLite

** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
** of the SQL statement that triggered the call to the [xUpdate] method of the
** [virtual table].
*/
int sqlite3_vtab_on_conflict(sqlite3 *);

/*
** CAPI3REF: Determine The Collation For a Virtual Table Constraint
**
** This function may only be called from within a call to the [xBestIndex]
** method of a [virtual table implementation]. 
**
** The first argument must be the database handle with which the virtual 
** table is associated (the one passed to the [xConnect] or [xCreate] method 
** to create the sqlite3_vtab object. The second argument must be an index
** into the aConstraint[] array belonging to the sqlite3_index_info structure
** passed to xBestIndex. This function returns a pointer to a buffer 
** containing the name of the collation sequence for the corresponding
** constraint.
*/
SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3*, int);

/*
** CAPI3REF: Conflict resolution modes
** KEYWORDS: {conflict resolution mode}
**
** These constants are returned by [sqlite3_vtab_on_conflict()] to

#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int nVTrans;                  /* Allocated size of aVTrans */
  Hash aModule;                 /* populated by sqlite3_create_module() */
  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
  VTable **aVTrans;             /* Virtual tables with open transactions */
  VTable *pDisconnect;    /* Disconnect these in next sqlite3_prepare() */
  void *pBestIndexCtx;          /* For sqlite3_vtab_collation() */
#endif
  Hash aFunc;                   /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int busyTimeout;              /* Busy handler timeout, in msec */

                      *pbIn, (sqlite3_uint64)mPrereq,
                      (sqlite3_uint64)(pNew->prereq & ~mPrereq)));

  return rc;
}


/*
** Context object used to pass information from whereLoopAddVirtual()
** to sqlite3_vtab_collation().
*/
struct BestIndexCtx {
  WhereClause *pWC;
  sqlite3_index_info *pIdxInfo;
  Parse *pParse;
};

/*
** If this function is invoked from within an xBestIndex() callback, it
** returns a pointer to a buffer containing the name of the collation
** sequence associated with element iCons of the sqlite3_index_info.aConstraint
** array. Or, if iCons is out of range or there is no active xBestIndex
** call, return NULL.
*/
const char *sqlite3_vtab_collation(sqlite3 *db, int iCons){
  struct BestIndexCtx *p = (struct BestIndexCtx*)db->pBestIndexCtx;
  const char *zRet = 0;
  if( p && iCons>=0 && iCons<p->pIdxInfo->nConstraint ){
    int iTerm = p->pIdxInfo->aConstraint[iCons].iTermOffset;
    Expr *pX = p->pWC->a[iTerm].pExpr;
    CollSeq *pC = sqlite3BinaryCompareCollSeq(p->pParse,pX->pLeft,pX->pRight);
    zRet = (pC ? pC->zName : "BINARY");
  }

    sqlite3DbFree(pParse->db, p);
    return SQLITE_NOMEM_BKPT;
  }

  bic.pWC = pWC;
  bic.pIdxInfo = p;
  bic.pParse = pParse;
  pSaved = pParse->db->pBestIndexCtx;
  pParse->db->pBestIndexCtx = (void*)&bic;

  /* First call xBestIndex() with all constraints usable. */
  WHERETRACE(0x40, ("  VirtualOne: all usable\n"));
  rc = whereLoopAddVirtualOne(pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn);

  /* If the call to xBestIndex() with all terms enabled produced a plan
  ** that does not require any source tables (IOW: a plan with mBest==0),

      rc = whereLoopAddVirtualOne(
          pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn);
    }
  }

  if( p->needToFreeIdxStr ) sqlite3_free(p->idxStr);
  sqlite3DbFreeNN(pParse->db, p);
  pParse->db->pBestIndexCtx = pSaved;
  return rc;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Add WhereLoop entries to handle OR terms.  This works for either
** btrees or virtual tables.