Index Structures for Temporal and Multimedia Databases

by TOLGA BOZKAYA This thesis proposes index structures for efficient evaluation of temporal queries in temporal databases and similarity based queries in multimedia databases. To support temporal operators and to increase the efficiency of temporal queries, indexing based on temporal attributes is required. A temporal database can support two notions of time. Valid time is the time when a data entity is valid in reality, and the transaction time is the time when a data entity is recorded in the database. In this thesis, methods for indexing time intervals in transaction time and valid time databases are proposed. Transaction time databases are append only databases. Data is never deleted from the database, and data versions that were deleted or modified are stored as historical versions. This thesis proposes indexing current and historical versions of temporal entities separately to exploit the behavior of transaction time data. Two structures, namely IB+tree and AD*-tree, are proposed for indexing the historical data versions. IB+tree (Interval B+tree) is an augmented B+tree to support interval search queries. Similarly, AD*-tree is an augmented AD-tree (Append-Delete tree) which is a onedimensional tree structure specifically designed for FIFO domains. Some experimental and analytical results are provided for evaluation of these proposed structures. In valid time databases, temporal data versions can be inserted, deleted, or modified at any point in time. Furthermore, their lifespans can extend into the future.