ObjectDatabase++ Documentation

Delevopers ObjectDatabase++ API Delete Object

DeleteObject

DeleteObject read in an object an marks it for deletion, the object remains within the database until CommitTransaction is called, this operation can be undone by calling RestoreObject before commiting the transaction if an incorrect object is found.

unsigned int DeleteObject (
	unsigned int tableID,
	__int64 objectID = 0,
	CODBPP::Object *object = NULL
);
unsigned int DeleteObject (
	unsigned int tableID,
	CODBPP::Mode operation,
	CODBPP::Object *object = NULL,
	unsigned int index = 0,
	const void *key = NULL,
	unsigned int *matchingRow = NULL
);

Parameters

tableID	The table ID defining the table's handle.
objectID	The object ID defining the object's handle when using the shorthand version.
operation	Valid operations only
object	For the returned object addresses.
index	The index value, 0 for object ID hash index, 1 for the first defined index
key	The key value used in any find comparison.
matchingRow	Used to identify which row of a sub-table field, within the current object has the matching multi-entry index value.

Return Values

If the method succeeds, the return value is zero else see error codes for more details.

Remarks

Once DeleteObject has deleted an object, all the index values held by that object can be reused by any other object during the transaction, except for the objectID which is not reusable.

If the objectID is zero (0), then DeleteObject will try and delete the last object successfully read by ReadObject.

DeleteObject will not delete an added object, use RestoreObject to delete and added object.

DeleteObject will attempt to lock twenty times longer if the object is above the transaction’s high water mark, if the object is below the mark than DeleteObject will return an error if unable to gain object lock.

DeleteObject will allow the operation of NO_WAIT and SHORT_WAIT if the object is known to be locked and there is little need to wait the entire timeout period before returning CODBPP::UNABLE_TO_LOCK_OBJECT.

Example Use

CODBPP::Object object;
struct FixedObject{
   int First;
   double Second;
} *fixedObject;
char16_t *userName = _T"UserName";
unsigned int error;
if((error = database.BeginTransaction()) == NO_ERROR){
   if((error = database.OpenTable(1)) == NO_ERROR){
      if((error = database.DeleteObject(1,CODBPP::EQUALTO,&object,1,userName)) == NO_ERROR){
         fixedObject = (struct FixedObject*)object.fixed;
         if(fixedObject->First == 123 && fixedObject->Second == 0)
            error = database.CommitTransaction();
         else error = database.AbortTransaction();
      }
      else{
         if(error == (0x10000 | CODBPP::NOT_FOUND_INDEX_KEY)){
            MessageBox(_T"Object not found");
            error = NO_ERROR;
         }
      }
   }
}
if(error && database.GetErrorMessage(&message) == NO_ERROR)
   MessageBox(message);
database.EndTransaction();

Also See

AddObject, NewObject, ReadObject, RestoreObject, RewriteObject, SearchIndex