1. A method for information warehouse construction in memory of a hardware computer processor, comprising: accepting input from a user at a front-end graphical user interface; generating a plurality of commands employing declarative statements in an information warehouse language and performing loading or copying of data using: information warehouse (IW) level commands that when implemented provide support for both structured and unstructured data, indexing engine level commands configured to perform tasks specified by the commands from a user interface, source mapping commands configured to perform at least one of: a data format transformation, source-to-target complex schema matching, and complex data value mapping, data loading commands configured to perform at least one of: a data format transformation, source-to-target complex schema matching, and complex data value mapping, and dimension level commands that when implemented provide support for both structured and unstructured data and include at least one of: creating a dimension, altering the dimension, and dropping the dimension; and constructing an information warehouse based on a script comprising the IW level commands and the dimension level commands according to the language specification for information warehouse construction; and providing error correction for data loaded from a source file into the information warehouse using: an abort command that uses a pending log to return the information warehouse to a consistent break point prior to a data load into the information warehouse so that operational details of maintaining data integrity for both the structured and the unstructured data are hidden from a user of the abort command, such that a load command automatically resumes loading data into the information warehouse from a last consistent breakpoint of a data load, while maintaining data integrity for both the structured and the unstructured data by performing system level tasks that are hidden from a user of the load command; an undo command, operating with regard to the source file, that uses a checkpoint log to automatically return the information warehouse to a state of the information warehouse prior to loading of the source file, while maintaining data integrity for both the structured and the unstructured data by performing system level tasks that are hidden from a user of the undo command; and a redo command, operating with regard to the source file, that uses the checkpoint log to automatically return the information warehouse to a state of the information warehouse after loading of the source file, wherein the loading of the source file has previously been undone, and while maintaining data integrity for both the structured and the unstructured data by performing system level tasks that are hidden from a user of the redo command.