Object Relational Mapping (ORM) System
An Object Relational Mapping (ORM) System is an Object-Oriented Programming System that can convert data between incompatible software programming systems.
- AKA: ORM, Object-Relational Mapping, O/RM, O/R, O/R Mapping Tool.
- Example(s):
- Counter-Example(s):
- See: Computer Science, Computer Programming, Type System, Object-Oriented, Object Database, Object-Oriented Programming, Data Management, Object (Computer Science), Scalar (Computing), Attribute (Computing), Object Relational (O/R) Impedance Mismatch System.
References
2021a
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Object–relational_mapping Retrieved:2021-1-17.
- Object-relational mapping (ORM, O/RM, and O/R mapping tool!) in computer science is a programming technique for converting data between incompatible type systems using object-oriented programming languages. This creates, in effect, a "virtual object database” that can be used from within the programming language. There are both free and commercial packages available that perform object-relational mapping, although some programmers opt to construct their own ORM tools.
In object-oriented programming, data-management tasks act on objects that are almost always non-scalar values. For example, consider an address book entry that represents a single person along with zero or more phone numbers and zero or more addresses. This could be modeled in an object-oriented implementation by a "Person object” with an attribute/field to hold each data item that the entry comprises: the person's name, a list of phone numbers, and a list of addresses. The list of phone numbers would itself contain "PhoneNumber objects" and so on. Each such address-book entry is treated as a single object by the programming language (it can be referenced by a single variable containing a pointer to the object, for instance). Various methods can be associated with the object, such as methods to return the preferred phone number, the home address, and so on.
By contrast, many popular database products such as SQL database management systems (DBMS) are not object-oriented and can only store and manipulate scalar values such as integers and strings organized within tables. The programmer must either convert the object values into groups of simpler values for storage in the database (and convert them back upon retrieval), or only use simple scalar values within the program. Object-relational mapping implements the first approach.[1]
The heart of the problem involves translating the logical representation of the objects into an atomized form that is capable of being stored in the database while preserving the properties of the objects and their relationships so that they can be reloaded as objects when needed. If this storage and retrieval functionality is implemented, the objects are said to be persistent.
- Object-relational mapping (ORM, O/RM, and O/R mapping tool!) in computer science is a programming technique for converting data between incompatible type systems using object-oriented programming languages. This creates, in effect, a "virtual object database” that can be used from within the programming language. There are both free and commercial packages available that perform object-relational mapping, although some programmers opt to construct their own ORM tools.
2021b
- (SQLAlchemy, 2020) ⇒ https://docs.sqlalchemy.org/en/13/orm/tutorial.html Retrieved:2021-1-17.
- QUOTE: The SQLAlchemy Object Relational Mapper presents a method of associating user-defined Python classes with database tables, and instances of those classes (objects) with rows in their corresponding tables. It includes a system that transparently synchronizes all changes in state between objects and their related rows, called a unit of work, as well as a system for expressing database queries in terms of the user defined classes and their defined relationships between each other.
2013
- (Murakami et al., 2013) ⇒ Tadashi Murakami, Toshiyuki Amagasa, and Hiroyuki Kitagawa (2013). “DBPowder: A Flexible Object-Relational Mapping Framework Based on a Conceptual Model". In: Proceedings of the 37th Annual IEEE Computer Software and Applications Conference (COMPSAC 2013). DOI:10.1109/COMPSAC.2013.93.
- QUOTE: This paper proposes an ORM framework called DBPowder that addresses the difficulty in handling simple and complex correspondences. DBPowder supports (1) by Extended Entity-Relationship (EER) model, and it supports (2) by introducing ObjectView, a graph-based object description form over the EER model. A combination of the EER model and ObjectView provides a flexible data model, and it enables DBPowder to handle both simple and complex correspondences for support the different development stages.