core/sql/optimizer/TriggerDB.h

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#ifndef TRIGGERDB_H
#define TRIGGERDB_H
/* -*-C++-*-
*************************************************************************
*
* File:         TriggerDB.h
* Description:	Part of the SchemaDB, a hash dictionary of triggers
* Created:		06/23/98
*
*
*
*************************************************************************
*/

#include "Triggers.h"

//-----------------------------------------------------------------------------
// classes defined in this file:

class TableOp;
class TriggerDB;

//-----------------------------------------------------------------------------

static const short TRIGGERDB_INIT_SIZE	= 20;

// the TriggerDB will be cleaned up if the threashold is exceeded 
// this is a simple mechanism to eliminate overflow, when entries in the DB
// are kept across statements in the ContextHeap. <aviv>
static const short TRIGGERDB_THRASHOLD = TRIGGERDB_INIT_SIZE;

//-----------------------------------------------------------------------------
//
// -- class TableOp

class TableOp : public NABasicObject 
{
public:

  // explicit ctor
  TableOp(QualifiedName &subjectTable, ComOperation operation)
    : subjectTable_(subjectTable),
      operation_(operation)
  {}

  inline NABoolean operator == (const TableOp &other) const 
  { return operation_==other.operation_ && 
    subjectTable_ == other.subjectTable_; }

  //ULng32 hash() const;
    
  void print(ostream & os) const;

  QualifiedName	  subjectTable_;
  ComOperation	  operation_;
};

//-----------------------------------------------------------------------------
//
// -- class TriggerDB

class TriggerDB : public NAHashDictionary<TableOp, BeforeAndAfterTriggers> 
{
public:
  static ULng32 HashFunction(const TableOp & key);

  TriggerDB(CollHeap *heap)
    : NAHashDictionary<TableOp, BeforeAndAfterTriggers>  // enforce uniqueness
	(&HashFunction, TRIGGERDB_INIT_SIZE, TRUE, heap)
  {}

  // clear the Trigger DB and destroy (free memory) of all entries
  void clearAndDestroy();

  // when triggerDB is allocated from the contextHeap (see Trigger::Heap()),
  // then we must make sure that after each statement, the recursion counter 
  // of every Trigger object must be reset to 0, and in case triggerDB grows
  // beyond its THRASHOLD, we need to deallocate it.
  NABoolean cleanupPerStatement();
  
  // main driver
  BeforeAndAfterTriggers *getTriggers(QualifiedName &subjectTable, 
				      ComOperation   operation, 
				      BindWA        *bindWA);

  void print(ostream& os) const;

  NABoolean isHiveTable(QualifiedName& name);

protected:
  // This method validates (timestamp check) the return value before
  // returning. NULL is returned if no entry was found, given the key.
  // This function is relevant when allocating the triggerDB from the context 
  // heap. A non-valid entry is also removed from the DB .
  // NOTE: using the superclass's getFirstValue will NOT VALIDATE the entry
  BeforeAndAfterTriggers* getValidEntry(const TableOp * key, BindWA * bindWA);
};

#endif /* TRIGGERDB_H */