Date of Award


Publication Type

Master Thesis

Degree Name



Computer Science


Applied sciences


Christie Ezeife




An object-oriented database is represented by a set of classes connected by their class inheritance hierarchy through superclass and subclass relationships. An object-oriented database is suitable for capturing more details and complexity for real world data. Existing algorithms for mining multiple databases are either Apriori-based or machine learning techniques, but are not suitable for mining multiple object-oriented databases.

This thesis proposes an object-oriented class model and database schema, and a series of class methods including that for object-oriented join ( OOJoin) which joins superclass and subclass tables by matching their type and super type relationships, mining Hierarchical Frequent Patterns ( MineHFPs) from multiple integrated databases by applying an extended TidFP technique which specifies the class hierarchy by traversing the multiple database inheritance hierarchy. This thesis also extends map-gen join method used in TidFP algorithm to oomap-gen join for generating k-itemset candidate pattern to reduce the candidate itemset generation by indexing the (k-1)-itemset candidate pattern using two position codes of start position and end position codes tied to inheritance hierarchy level. Experiments show that the proposed MineHFPs algorithm for mining hierarchical frequent patterns is more effective and efficient for complex queries.