9. A method of operating a computer system to create a relational database schema from a semantic object model, comprising the steps of: creating, in response to a user input, one or more semantic objects, each representing an item about which data is stored in a relational database; retrieving from a memory of the computer system a plurality of predefined profiles, each profile defining default values of one or more properties of a corresponding attribute; selecting, in response to user input, one of the plurality of predefined profiles and associating the selected profile with a semantic object in the semantic object model; automatically creating an attribute in the associated semantic object based on the selected profile, the attributes including simple value attributes that represent a data entry in a single column of the relational database group attributes having one or more member attributes that represent a logical collection of attributes and object link attributes that represent relationships between the semantic objects in the semantic object model, wherein each attribute has one or more properties having default values that are defined by the one or more properties of the selected profile; and translating the semantic objects and their associated attributes into a relational database schema.
10. The method of claim 9, wherein the computer system stores a list of attributes that are associated with each profile, the method further comprising the steps of: determining whether a user has modified a default value of the one or more properties of a profile; and automatically updating a corresponding property in each attribute that is associated with the profile to conform to a new value of the modified property.