Adding content to 108-enterprise-patterns

src/roadmaps/software-design-architecture/content/108-enterprise-patterns/101-identity-maps.md

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 # Identity Maps
 
+Identity Maps is a pattern used in enterprise application development to maintain a map of objects that have been loaded from the database, keyed by their unique identifier. It is used to ensure that multiple copies of the same object are not created in memory when the same data is accessed multiple times.
 
+The identity map pattern is typically used in conjunction with an ORM (Object-Relational Mapping) tool. When an object is loaded from the database, it is first checked against the identity map to see if it has already been loaded. If it has, the existing object is returned, instead of creating a new copy.
 
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src/roadmaps/software-design-architecture/content/108-enterprise-patterns/102-use-cases.md

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 # Use Cases
 
+Use Cases are a pattern used in enterprise application development to represent the functional requirements of a system. They describe the interactions between the system and its users, and the steps that are required to accomplish a specific goal. Use cases are a way to capture the requirements of the system in a way that is easily understood by both the development team and the stakeholders.
 
+A use case is a description of a sequence of actions that a system performs in response to a request from a user, in order to achieve a specific goal. A use case typically includes:
+
+- The actor (user) who initiates the action
+- The goal that the actor wants to achieve
+- The steps required to achieve the goal, including any alternative paths or error conditions
+- The expected outcome of the interaction
+
+Use cases are often used to drive the design and development of the system, as they provide a clear and detailed understanding of the requirements.
 
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src/roadmaps/software-design-architecture/content/108-enterprise-patterns/103-repositories.md

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 # Repositories
 
+Repositories are a pattern used in enterprise application development to provide a consistent and abstracted way to access data storage. Repositories act as an abstraction layer between the application and the data storage, providing a consistent and simple API for data access and manipulation.
 
+A repository is a pattern that can be used to organize the data access code and encapsulate the logic of retrieving and storing objects. Repositories provide a way to separate the concerns of the data access from the rest of the application, allowing the application code to be written against an interface and not a specific data storage technology.
 
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src/roadmaps/software-design-architecture/content/108-enterprise-patterns/104-mappers.md

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 # Mappers
 
+Mappers are a pattern used in enterprise application development to provide a consistent and abstracted way to map between different data models. They act as an abstraction layer between the application and the data storage, providing a consistent and simple API for data transformation.
 
+A mapper is a component that can be used to convert data from one format or model to another. For example, a mapper can be used to convert data from a database model to a domain model, or from a domain model to a data transfer object (DTO).
 
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