1. A value formatting system for determining format specifications in reports, the value formatting system comprising: a computer: a format collection unit that collects data value format attributes and patterns for one or more value types in a report from a first source and data value format attributes and patterns for the one or more value types from a second source, the data value format attributes and patterns being used to convert a data value from an internal format into a string of characters for display purposes, wherein each of the data value format patterns comprises a substitution mask that includes one or more meta-characters; a format repository that stores the collected data value format attributes and patterns; and a format merging unit that merges the collected data value format attributes and patterns into a single format specification for each of the value types, wherein, for each value type, the format merging unit merges the collected data value format attributes and patterns associated with the respective value type according to a precedence list that specifies an order of precedence between the data value format attributes and patterns collected from the first source and the data value format attributes and patterns collected from the second source, and wherein one or more of the format collection unit and the format merging unit are executable by the computer.