Things, identities and relationships

Before joining information, establish what each statement describes. Then read every connection as a claim you could explain—and challenge—in an ordinary sentence.

One address. More than one thing.

A report arrives with the subject “14 Orchard Road”. It sounds precise. In our fictional case, Harbour Court is the building at that address and contains Flat 1 and Flat 2. Does the report concern the whole building, one dwelling, or a record describing a legal interest? The address helps you locate the situation. It does not answer that question.

This is a useful place to begin modelling: not “which fields should we add?”, but “what are we talking about?” The building, dwellings, inspection and report can each be identified and described. In modelling language, each can be a resource. Something need not be physical to count: an inspection event and a particular document version can matter just as much as a wall or room.

The connections say different things. Harbour Court contains Flat 1 and Flat 2. An address description locates the building in this example. A title record describes the extent stated in that record; the address alone does not establish whether that extent is the whole building or one flat. None of these statements says the connected subjects are identical.

Four questions hidden inside “the property”

An identifier helps only if we know what it identifies. A report reference may identify a document family while another reference identifies one version. A reference copied into a dwelling record might still identify the building. Matching characters are a reason to examine the scheme and evidence, not permission to merge everything that carries them.

Identity is a particularly strong claim. If we say two references identify the same subject, information attached to either must be interpreted on that basis. Mistaking a title record for a building could turn a change to the record into an apparent change to the physical building. Keeping the subjects distinct lets us connect useful evidence without inventing that consequence.

A line is a sentence with work to do

A relationship makes a specific connection. Consider “Report version 2 describes the inspection concerning Flat 1”. Read it in two parts: report version 2 describes the inspection; the inspection concerns Flat 1. The report did not perform the inspection, and the dwelling did not issue the report. Direction and a meaningful verb preserve those differences.

Compare four ordinary connections. “Flat 1 is contained in Harbour Court” concerns a part and a whole. “Report version 2 mentions Flat 1” is documentary reference. “Flat 1 is classified as a dwelling” assigns a kind. “These two records refer to the same inspection” is an identity claim about their subject. Replacing each with an unlabelled line erases the distinction the reader needs to judge.

Likewise, a topic tree that places “Roof condition” under “Building fabric” organises subjects for reading. It does not state which roof is part of which building. The names and choices chapter develops that distinction.

Some connections need a setting

“Alex is the buyer” sounds complete until two transactions are on the desk. In the Harbour Court case, Alex participates as buyer in transaction T, the proposed sale of Flat 1, during the recorded period 1–30 September 2026. That is the whole statement we have evidence for. It does not describe Alex's role in another transaction or outside that period.

A statement about participation may also need a source: for this example, a fictional participation note for transaction T records Alex's role and period. A reviewer can ask about that note without deciding how the statement is encoded. The same habit applies to an organisation acting for another party, or a report used as evidence for a particular assessment: identify the relationship's setting before deciding that a simple line is enough.

What can change while the subject continues?

At Harbour Court, report version 1 was issued on 14 August and version 2 on 20 August. The correction changes the description of an access limitation; both describe the 12 August inspection. There was no new visit in this story. A change to its description is therefore not a new inspection. The roles and change chapter works through the evidence.

Subdivision is harder. If Flat 1 is divided into two dwellings, the label “converted” cannot decide whether the original dwelling continues. We would need the model's identity criteria and the facts of the alteration. Time passing does not make every change a state of the same subject.

Identity, role and state are different questions

A role describes participation in a setting; a recorded state describes a subject at a relevant time. Neither replaces the question “which subject is this?” Continue at People, roles and change for multiple arrangements and the difference between an event and its changing account.

A useful review question is specific

“The property link is unclear” flags a concern. “Does this link mean the building contains the dwelling, or that the report mentions it? The current wording would let a reader apply a flat-only finding to the whole building” identifies the claim and its consequence. That is a contribution a modeller and a practitioner can examine together.

Method background: classes and relationships and the decision register. These cases teach the identity and relationship questions; they do not approve a property-identity model or describe a real legal title.