摘要:
Data may be modeled as an undirected graph. A set of entities and a set of attributes may be defined. A set of relationships may be defined to represent semantic associations with each association connecting at least two entities. Attributes may be associated with entities rather than with relationships. A hierarchical query language with a set of atomic operations on modeled data may be employed. The modeled data may be displayed on a display unit.
摘要:
A method and system are disclosed for use with an ETL (Extract, Transform, Load) process, comprising optimizing a filter expression to select a subset of data and evaluating the filter expression on the data after the extracting, before the loading, but not during the transforming of the ETL process. The method and system optimizes the filtering using a pipelined evaluation for single predicate filtering and an adaptive optimization for multiple predicate filtering. The adaptive optimization includes an initial phase and a dynamic phase.
摘要:
A system and method for ensuring large and frequent updates to a data warehouse. The process leverages a set of temporary staging tables to track the updates. A set of intermediate steps are performed to accomplish bulk deletions of the outdated changed records, and perform modifications to the map tables for models such as snowflake. Finally, bulk load operations load the updates and insert them into the final dimension tables. The process ensures performance comparable to insertion-only schemes with at most only slight performance degradation. Furthermore, a modified process is applied on the newfact data warehouse dimension model. The process can be readily adapted to handle star schema and other hierarchical data warehouse models.
摘要:
A method and system for coping with slice and dice operations in data warehouses is disclosed. An external approach may be utilized, creating queries using structured query language on a computer. An algorithm may be used to rewrite the queries. The resulting predicates may be joined to dimension tables corresponding to fact tables. An internal approach may be utilized, using aggregation functions with early aggregation for creating the queries. The results of the slice and dice operations may be outputted to a user on a computer monitor.
摘要:
A system and method for ensuring large and frequent updates to a data warehouse. The process leverages a set of temporary staging tables to track the updates. A set of intermediate steps are performed to accomplish bulk deletions of the outdated changed records, and perform modifications to the map tables for models such as snowflake. Finally, bulk load operations load the updates and insert them into the final dimension tables. The process ensures performance comparable to insertion-only schemes with at most only slight performance degradation. Furthermore, a modified process is applied on the newfact data warehouse dimension model. The process can be readily adapted to handle star schema and other hierarchical data warehouse models.
摘要:
System and methods manage concurrent ETL processes accessing a database. Exemplary embodiments include a method for concurrency management for ETL processes in a database having database tables and communicatively coupled to a computer, the method including establishing a session lock for the database, determining that a current ETL process is accessing the database at a current time, associating a current expiration time with the session lock, the expiration time being stored in a lock table in the database, sending the session lock to the current ETL process and performing ETL-level locking for the current ETL process.
摘要:
A method for use with an information (or data) warehouse comprises managing the information warehouse with instructions in a declarative language. The instructions specify information warehouse-level tasks to be done without specifying certain details of how the tasks are to be implemented, for example, using databases and text indexers. The details are hidden from the user and include, for example, in an information warehouse having a FACT table that joins two or more dimension tables, details of database level operations when structured data are being handled, including database command line utilities, database drivers, and structured query language (SQL) statements; and details of text-indexing engines when unstructured data are being handled. The information warehouse is managed in a dynamic way in which different tasks—such as data loading tasks and information warehouse construction tasks—may be interleaved (i.e., there is no particular order in which the different tasks must be completed).
摘要:
A method, system, and computer program product are disclosed. Exemplary embodiments of the method, system, and computer program product may include hardware, process steps, and computer program instructions for supporting versioning in a data warehouse. The data warehouse may include a data warehouse engine for creating a data warehouse including a fact table and temporary tables. Updated or new data records may be transferred into the data warehouse and bulk loaded into the temporary tables. The updated or new data records may be evaluated for attributes matching existing data records. A version number may be assigned to data records and data records may be marked as being the most current version. Updated and new data records may be bulk loaded from the temporary tables into the fact table when a version number or a version status is calculated.
摘要:
A system and method for ensuring large and frequent updates to a data warehouse. The process leverages a set of temporary staging tables to track the updates. A set of intermediate steps are performed to accomplish bulk deletions of the outdated changed records, and perform modifications to the map tables for models such as snowflake. Finally, bulk load operations load the updates and insert them into the final dimension tables. The process ensures performance comparable to insertion-only schemes with at most only slight performance degradation. Furthermore, a modified process is applied on the newfact data warehouse dimension model. The process can be readily adapted to handle star schema and other hierarchical data warehouse models.
摘要:
A method of data loading for large information warehouses includes performing checkpointing concurrently with data loading into an information warehouse, the checkpointing ensuring consistency among multiple tables; and recovering from a failure in the data loading using the checkpointing. A method is also disclosed for performing versioning concurrently with data loading into an information warehouse. The versioning method enables processing undo and redo operations of the data loading between a later version and a previous version. Data load failure recovery is performed without starting a data load from the beginning but rather from a latest checkpoint for data loading at an information warehouse level using a checkpoint process characterized by a state transition diagram having a multiplicity of states; and tracking state transitions among the states using a system state table.