AttrOperator Constructor
An attribute operator types can be defined as
AttrOperator attrOperator = new AttrOperator(AttrOperator.aopEQ);
and subsequently used as
if (attrOperator.attrOperator == AttrOperator.aopEQ) ....
AttrType Constructor
An attribute type of String can be defined as
AttrType attrType = new AttrType(AttrType.attrString);
and subsequently used as
if (attrType.attrType == AttrType.attrString) ....
The buffer manager class, it allocates new pages for the
buffer pool, pins and unpins the frame, frees the frame
page, and uses the replacement algorithm to replace the
page.
This function compares a tuple with another tuple in respective field, and
returns:
0 if the two are equal,
1 if the tuple is greater,
-1 if the tuple is smaller,
The tuple is returned
All this function has to do is to get 1 tuple from one of the Iterators
(from both initially), use the sorting order to determine which one
gets sent up.
IndexType Constructor
An index type can be defined as
IndexType indexType = new IndexType(IndexType.Hash);
and subsequently used as
if (indexType.indexType == IndexType.Hash) ....
LogicalOperator Constructor
A logical operator can be defined as
LogicalOperator logicalOperator =
new LogicalOperator(LogicalOperator.lopOR);
and subsequently used as
if (logicalOperator.logicalOperator == LogicalOperator.lopOR) ....
create a scan with given keys
Cases:
(1) lo_key = null, hi_key = null
scan the whole index
(2) lo_key = null, hi_key!= null
range scan from min to the hi_key
(3) lo_key!= null, hi_key = null
range scan from the lo_key to max
(4) lo_key!= null, hi_key!= null, lo_key = hi_key
exact match ( might not unique)
(5) lo_key!= null, hi_key!= null, lo_key < hi_key
range scan from lo_key to hi_key
SelectType Constructor
A selected type can be defined as
SelectType selectType = new SelectType(SelectType.SelBoth);
and subsequently used as
if (selectType.selectType == SelectType.SelBoth) ....
TupleOrder Constructor
A tuple ordering can be defined as
TupleOrder tupleOrder = new TupleOrder(TupleOrder.Random);
and subsequently used as
if (tupleOrder.tupleOrder == TupleOrder.Random) ....