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SQLAlchemy is an open-source Python library that provides an SQL toolkit (called "SQLAlchemy Core") and an Object Relational Mapper (ORM) for database interactions. It allows developers to work with databases using Python objects, enabling efficient and flexible database access.
One of the arguments against using an OODBMS is that it may not be able to execute ad-hoc, application-independent queries. [citation needed] For this reason, many programmers find themselves more at home with an object-SQL mapping system, even though most object-oriented databases are able to process SQL queries to a limited extent. Other ...
Apache Cayenne, open-source for Java; Apache OpenJPA, open-source for Java; DataNucleus, open-source JDO and JPA implementation (formerly known as JPOX) Ebean, open-source ORM framework; EclipseLink, Eclipse persistence platform; Enterprise JavaBeans (EJB) Enterprise Objects Framework, Mac OS X/Java, part of Apple WebObjects
This is useful when one needs to model and enforce strict business processes on the data in the domain layer that do not map neatly to the persistent data store. [2] The layer is composed of one or more mappers (or Data Access Objects), performing the data transfer. Mapper implementations vary in scope.
Java: Open source: Eclipse Public License Version 1.0 (EPL) and Eclipse Distribution License Version 1.0 (EDL) 2.4.2 / July 4, 2013 JPA 2.0: Entity Framework Core.NET Open Source: Apache License 2.0 6.0 / November 10, 2021 Hibernate: Java: Open source: GNU Lesser General Public License: 5.4.31 / April 30, 2021 JPA 2.0: MyBatis/iBATIS: Cross ...
A one-to-many relationship between records in patient and records in appointment because patients can have many appointments and each appointment involves only one patient. [ 1 ] A one-to-one relationship is mostly used to split a table in two in order to provide information concisely and make it more understandable.
Object–role modeling (ORM) is used to model the semantics of a universe of discourse. ORM is often used for data modeling and software engineering . An object–role model uses graphical symbols that are based on first order predicate logic and set theory to enable the modeler to create an unambiguous definition of an arbitrary universe of ...
For example, take a car and an owner of the car. The car can only be owned by one owner at a time or not owned at all, and an owner could own zero, one, or multiple cars. One owner could have many cars, one-to-many. In a relational database, a one-to-many relationship exists when one record is related to many records of another table. A one-to ...