include/PredicateImpl.h

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by www.databasecache.com                           *
   3  *   Contact: praba_tuty@databasecache.com                                 *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15   ***************************************************************************/
  16 #ifndef PREDICATE_IMPL_H
  17 #define PREDICATE_IMPL_H
  18 #include<DataType.h>
  19 #include<Predicate.h>
  20 class TableImpl;
  21 class Table;
  22 class PredicateImpl:public Predicate
  23 {
  24     //Members set during initialization of the term
  25     char fldName1[IDENTIFIER_LENGTH];
  26     char fldName2[IDENTIFIER_LENGTH];
  27     ComparisionOp compOp;
  28     void *operand;
  29     LogicalOp logicalOp;
  30     PredicateImpl *lhs;
  31     PredicateImpl *rhs;
  32
  33     //Members set during execution
  34     void *tuple; //pointer to the tuple
  35
  36     //This will be set before calling evaluate
  37     TableImpl *table;
  38
  39     public:
  40     PredicateImpl(){ operand = NULL; lhs = rhs = NULL; }
  41     ~PredicateImpl(){}
  42
  43     void setTerm(const char* fName1, ComparisionOp op, const char *fName2);
  44
  45     //Operand should be of the same type of the field.This is must
  46     void setTerm(const char* fName1, ComparisionOp op, void *opnd);
  47
  48     void setTerm(Predicate *p1, LogicalOp op, Predicate *p2 = NULL);
  49
  50     void* valPtrForIndexField(const char *name);
  51
  52     int evaluate(bool &result);
  53
  54     void setTable(Table *tbl);
  55     void setTuple(void *tpl);
  56
  57     //check predicate, whether it has field name and == operator
  58     //and does not have OR, NOT operator
  59     // TODO:: expression like !(f1 !=100) wont be optimized for now
  60     bool pointLookupInvolved(const char *fName);
  61
  62 };
  63
  64 #endif