In software development, "PO", "VO", "DTO" and "Entity" are common naming conventions used to represent different concepts and roles. Here are their common meanings:
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PO (Persistence Object): PO is the abbreviation of persistence object, which is used to represent objects that correspond to the database table structure. POs usually contain properties that correspond to database table fields and provide corresponding getter and setter methods. PO is mainly used for data exchange and persistence operations between applications and databases.
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VO (Value Object): VO is the abbreviation of value object, which is used to represent an object with a set of related properties. VO is usually used to encapsulate some business logic related data and transfer it between different layers. The properties of a VO object can be of any type, whether they are basic types, custom types, or other objects.
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DTO (Data Transfer Object): DTO is the abbreviation of data transfer object, which is used to represent objects transferred between different layers or modules. DTOs are often used to encapsulate multiple properties in order to pass data between remote calls or different layers. The properties of a DTO object are usually related to business requirements and can contain other objects or nested DTOs.
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Entity: Entity represents an entity object, usually corresponding to a concept in the domain model. Entity objects contain properties and behaviors related to the business domain and are used to represent the state and behavior of business entities. Entity objects are usually mapped to database table structures and can contain business logic and data manipulation methods.
It's important to note that the specific meaning of these terms may vary between different development teams, frameworks, or projects. In a specific project, these objects can be defined and used according to the team's agreements and needs.