Schema Evolution for Data Warehouse: A Survey

Data warehouse is considered as the core component of the modern decision support systems. Due to the major support of data warehouse in the daily transaction of an enterprise, the requirements for the design and the implementation of DW are dynamic and subjective. This dynamic nature of the data warehouse may reflect the evolution in the data warehouse. Data warehouse evolution may be focused on three approaches namely schema evolution, schema versioning and view maintenance. Evolution of the data warehouse may often change their data and structure (schema changes). These schema changes may be consider according to the change in structure, software and users‟ requirement. Schema evolution in data warehouse consists of various level namely structural level, conceptual level and behavioural level. This paper mainly focuses on schema evolution and proposes the operators to handle the creation and evolution of aggregated fact table. Our work is to do comparative study for various approaches of schema evolution.