What is a Data Dictionary?

Company data & APIs
Data contracts & exchange formats
3 min read

The short answer

A data dictionary documents field meanings, formats, permitted values and relevant interpretation rules.

Data Dictionary: why it matters

Automated company-data workflows need clear meanings and traceable transformations. An operation that runs successfully can still produce a result that is unsuitable for the intended business question.

How to assess it in practice

For data dictionary, retain the specific source, scope and effective date, and distinguish verified facts from assumptions before using the result in a decision. Start by defining the question the team needs to answer. Identify the relevant record or evidence, check its scope and date, and retain the reasoning behind the result. If evidence conflicts, keep that conflict visible for review.

Worked example

Illustrative workflow: a team reviewing a business adds a separate check for data dictionary. The reviewer’s task is to for data dictionary, retain the specific source, scope and effective date, and distinguish verified facts from assumptions before using the result in a decision. The outcome is recorded together with the supporting evidence; an unresolved question stays open rather than being converted into a positive result.

Illustrative scenario

A field called country is used differently by two teams. Define whether it means formation, address or operations before reconciling records.

Distinctions that matter

Data Dictionary belongs to the data contracts & exchange formats topic family. Read Data Schema alongside it to understand the adjacent question. Each page has its own intended scope; shared context does not make the concepts equivalent.

Evidence and review output

Review these

Schema and semantic definitions
Source-to-target transformations
Change detection and ownership

The review should produce

A versioned exchange agreement whose fields remain interpretable and whose failures have an accountable response.

Across this family

A machine-valid structure can still communicate the wrong business meaning. Define types, units, identifiers, null behaviour and change expectations, then preserve mappings between source and target. Owners need an agreed response when a schema or semantic contract stops being satisfied.

A note from practice

A useful dictionary explains each field's meaning, unit, scope, source and treatment of missing values. Include examples of interpretation, especially where business users might confuse registration, tax and internal identifiers.

Limits and common mistakes

The practical boundary is important: For data dictionary, retain the specific source, scope and effective date, and distinguish verified facts from assumptions before using the result in a decision. Do not substitute a related label for this check or assume that missing information is a negative finding. Source-specific and jurisdiction-specific rules require their own review.

Frequently asked questions

Which evidence should I review?

For this topic, focus on schema and semantic definitions, source-to-target transformations, change detection and ownership. The relevant source and dates should be retained with the finding.

How is Data Dictionary different from Data Contract?

A data contract specifies expectations between data producers and consumers about structure, meaning and service behaviour. The distinction matters because the evidence needed for that concept may not resolve the question addressed on this page.

What should the result of the review contain?

A versioned exchange agreement whose fields remain interpretable and whose failures have an accountable response. Preserve material conflicts instead of replacing them with an unexplained success flag.

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