Modeling language in the context of Programming code

The Unified Modeling Language (UML) is a general-purpose, object-oriented, visual modeling language that provides a way to visualize the architecture and design of a system, like a blueprint. UML defines notation for many types of diagrams which focus on aspects such as behavior, interaction, and structure.

UML is both a formal metamodel and a collection of graphical templates. The metamodel defines the elements in an object-oriented model such as classes and properties. It is essentially the same thing as the metamodel in object-oriented programming (OOP), however for OOP, the metamodel is primarily used at run time to dynamically inspect and modify an application object model. The UML metamodel provides a mathematical, formal foundation for the graphic views used in the modeling language to describe an emerging system.

A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. For instance, a data model may specify that the data element representing a car be composed of a number of other elements which, in turn, represent the color and size of the car and define its owner.

The corresponding professional activity is called generally data modeling or, more specifically, database design.Data models are typically specified by a data expert, data specialist, data scientist, data librarian, or a data scholar. A data modeling language and notation are often represented in graphical form as diagrams.

A computer language is a formal language for humans to communicate with a computer, not a natural language. In earlier days of computing (before the 1980s), the term was used interchangeably with programming language, but today, used primarily for taxonomy, is a broader term that encompasses languages that are not programming in nature. Sub-categories (with possibly contended hierarchical relationships) include:

• Construction
  • Programming – for controlling computer behavior
    • Command – for controlling the tasks of a computer, such as starting programs
    • Query – for querying databases and information systems
    • Transformation – for transforming the text of a formal language into text that meets a specific goal
  • Structural
    • Configuration – for writing configuration files
    • Data exchange – examples: JSON, XML
    • Markup – for annotating a document in a way that is syntactically distinguishable from the text, such as HTML
    • Page description – for describing the appearance of a printed page in a higher level than an actual output bitmap
    • Style sheet – for expressing the presentation of structured documents, such as CSS
• Modeling – for designing systems
  • Architecture description – for describing and representing system architecture
  • Hardware description – for modeling integrated circuits
• Simulation – for simulating
• Specification – for describing what a system should do

A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There are a wide variety of DSLs, ranging from widely used languages for common domains, such as HTML for web pages, down to languages used by only one or a few pieces of software, such as MUSH soft code. DSLs can be further subdivided by the kind of language, and include domain-specific markup languages, domain-specific modeling languages (more generally, specification languages), and domain-specific programming languages. Special-purpose computer languages have always existed in the computer age, but the term "domain-specific language" has become more popular due to the rise of domain-specific modeling. Simpler DSLs, particularly ones used by a single application, are sometimes informally called mini-languages.

The line between general-purpose languages and domain-specific languages is not always sharp, as a language may have specialized features for a particular domain but be applicable more broadly, or conversely may in principle be capable of broad application but in practice used primarily for a specific domain. For example, Perl was originally developed as a text-processing and glue language, for the same domain as AWK and shell scripts, but was mostly used as a general-purpose programming language later on. By contrast, PostScript is a Turing-complete language, and in principle can be used for any task, but in practice is narrowly used as a page description language.