http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Information Systems Constraint Language (ISyCL)
The Information Systems Constraint Language (ISyCL) is designed to support three primary activities: (1)adding textual constraints to models developed using graphical methods, (2)providing a neutral format for representing information contained in models from various methods, and (3j facilitating information systems implementation. Though ISyCL is based on first-order logic and set theory, its syntax is designed for readability. Layers of ISyCL have been defined for different types of users, thus shielding users from unnecessary constructs. Extensibility is provided through method slices which can be defined to support current modeling methods as well as future methods. ISyCL is unique in its support for combining relational and object-oriented database management, support for first-order logic and set theory, and support for both object and function metaclasses. No other language so fully supports information systems design and implementation.