Revise types of index used in databases from the class CS4221, National University of Singapore.
(Data Structure) B+ Tree Index vs RB Tree Index, Hash, Full-text
B+ tree has more nodes in one layer. Less IO for each search.
RB Tree is too deep.
(Space Saving)Sparse vs Dense
Sparse: not all keys will be indexed. Unstable search speed but less space.
Dense: all keys will be indexed. Faster search but more space.
(Physical Storage) Clustered vs Unclustered
Clustered index: rows in the disk are stored in the same order of index, so there can only be one cluster index for the rows.
With a non clustered index there is a second list that has pointers to the physical rows.
(Logical) Primary vs Secondary, Composited
Primary key is unique.
The secondary key can be not unique.
Revise types of index used in databases from the class CS4221, National University of Singapore.
(Data Structure) B+ Tree Index vs RB Tree Index, Hash, Full-text
B+ tree has more nodes in one layer. Less IO for each search. RB Tree is too deep.
(Space Saving)Sparse vs Dense
Sparse: not all keys will be indexed. Unstable search speed but less space. Dense: all keys will be indexed. Faster search but more space.
(Physical Storage) Clustered vs Unclustered
Clustered index: rows in the disk are stored in the same order of index, so there can only be one cluster index for the rows. With a non clustered index there is a second list that has pointers to the physical rows.
(Logical) Primary vs Secondary, Composited
Primary key is unique. The secondary key can be not unique.