A software architect models customer domains and maps them to excellent software constructs. The solution shall support future customer groups and expand to store additional information.
Tags, also called labels provide an informal ontology to classify customer data. Tags are extensible and are machine readable.
Comments empower users to store relevant unstructured information. Comments are only for human beings.
What are good approaches to provide searchable tags and labels and avoid wild growth of useless records?
Can you as a designer govern the ontology defined through labels?
What are good approaches to provide searchable tags and labels and avoid wild growth of useless records?
Can you as a designer govern the ontology defined through labels?
Tags
Tags add semantic information to business entities. Tags are often defined as a crowd ontology without enforced schemas. Invest in domain modeling to define and maintain tags and you will move tags to a full-fledged ontology other your domain models. This ontology supports meaningful search, segmentation and reporting over historical and geographical raw data.
Tags with associated values are also used to decorate unrelated entities with orthogonal information. For example you can associate geographical coordinates - GIS - to pictures, meetings, or addresses.
A tag has three parts
A tag has three parts
- an optional namespace to classify the tag in the overall ontology,
- a mandatory name to uniquely identify the tag in the context of its optional namespace,
- an optional value providing a specific information to the tag
For example we could defined a tag such as geo:longitude=50.167958 to provide the meta information of longitude to an entity. This tag has a namespace geo, a name longitude and a double value 50.167958.
The source code in modern Java is
public record Tag(String namespace, @NotNull String name, String value) implements Serializable {}
You should strongly consider the introduction of tag types to constrain the possible values of a specific tag. For example you can define that the namespace geo contains only the tags longitude and latitude. And both these tags have mandatory values of type double. Once your design supports tag types you can add generic validation rules in the user interface and in the business logic for all existing tags.
The ontology enforcement allows consistent reporting and data drilling over departments in your company and over time.
Comments
Comments provide human readable information and hints for entities.
An author writes a comment at a specific time. Usually comments shall be immutable. To respect human fallibility a correction mode can be supported. If changed the new comment replaces the older one and is marked as edited. The edition feature is part of the workflow and not part of the domain model.
An author can be another computer system. It can provide information about its actions through comments. If the deletion of comments is disabled, the comment history is an audit trail documenting what happened overtime with an entity instance.
Beware that the authors define an external identifier space. Policy should be defined to handle the fact that collaborators quit the company overtime and are no more active users; but they are still referenced as authors.
The code in Java is
public class Comment implements HasOid, HasTags {
private long oid;
private LocalDateTime created;
private String author;
private String text;
private Set<Tag> tags;
.... // getters and setters
}
Design
Our architecture follow the principles of domain driven design. Therefore comments are always associated with a specific domain of the application. For example often we model the persistence view of a domain through a database schema. Therefore each schema could have a persistence store for comments.
Tags are classification information associated with an instance and stored within the entity and the associated entity store such a a table.
Tag types are a medium to define an ontology and defines valid tag instances. A set of tag types shall always be associated with a specific domain of the application.
We provide a Java library BUS implementing these constructs. More information is available under tangly open source components.
Related concepts are discussed in our blog series
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