DuplicateKeyIndex

Possible structure for duplicate keys in tree index:

• key, list of record_ids

• key+record_id

• data record

• key, list of primary keys

How many blocks will read the DBMS to find 50 records satisfying the K = c condition in a a heap organized data file with 1.000.000 records 10 records on one page and having one unclustered B+tree index on K (non-unique search key)

• 53

• 8

• 1.000.000

• 100.00

How many blocks will read the DBMS to find 50 records satisfying the K = c condition in a heap organized data file with 1.000.000 records 10 records on one page and having one clustered B+tree index on K (non-unique search key)

• 53

• 100

• 8

• 3

In order to optimize B+ tree index is important:

• to maximize the fan-out

• to maximize the index entry size

• to maximize the height of the tree

How many blocks will read the DBMS to find in table MoviesActors(MovieID, ActorID) 20 records satisfying the MovieID = c condition in a heap organized data file with 1.000.000 records 10 records on one page and having one clustered B+tree index on (MovieID+ActorID).

• 3

• 4

• 5

• 100.000

How many blocks will read the DBMS to find in table MoviesActores(MovieID, ActorID) 20 records satisfying the ActorID = c condition in a heap organized data file with 1.000.000 records 10 records on one page and having one clustered B+tree index on (MovieID+ActorID).

• 3

• 4

• 5

• 100.000