Data records, which contain member fields and data fields
Header records, which describe the contents of the data source and how to load values from the data source to the database
Rules files contain records that translate the data of the data source to map it to the database. As part of that information, rules files can also contain header records. For example, the Sample.Basic database has a dimension for Year. If several data sources arrive with monthly numbers from different regions, the month itself might not be specified in the data sources. You must set header information to specify the month.
You can create a header record using one of the following methods:
Define header information in the rules file.
Rules file headers are used only during data loading or dimension building and do not change the data source. Header information set in a rules file is not used if the rules file also points to header records in the data source.
Define header information in the data source and, in the rules file, point to the header records.
Placing header information in the data source makes it possible to use the same rules file for multiple data sources with different formats, because the data source format is specified in the data source header (not in the rules file).
When you add one or more headers to the data source, you must also specify in the rules files the location of the headers in the data source. The rules file tells Essbase to read the header information as a header record (not as a data record). You can also specify the type of header information in each header record.
Header information defined in the data source takes precedence over header information defined in the rules file.