External Tables in Oracle 10g/11g Database: Part 1
http://www.packtpub.com/article/external-tables-oracle-10g-11g-database-part1 In this two-part article by Hector R. Madrid, we will learn about the External Tables in Oracle 10g/11g Database. When working in data warehouse environments, the Extraction—Transformation—Loading (ETL) cycle frequently requires the user to load information from external sources in plain file format, or perform data transfers among Oracle database in a proprietary format. This requires the user to create control files to perform the load. As the format of the source data regularly doesn't fit the one required by the Data Warehouse, a common practice is to create stage tables that load data into the database and create several queries that perform the transformation from this point on, to take the data to its final destination. A better approach, would be to perform this transformation 'on the fly' at load time. That is what External Tables are for. They are basically external files, managed either...