data-inventory-mapping

Data Inventory and Mapping for Classification

Overview

A data inventory is the foundational artefact for privacy compliance, providing a structured catalogue of all personal data processing activities across the organisation. GDPR Article 30 mandates that controllers maintain Records of Processing Activities (RoPA) containing specific fields including categories of personal data, purposes of processing, categories of recipients, and transfers to third countries. This skill focuses on building the data inventory that feeds into the RoPA, with emphasis on system-by-system discovery, data flow mapping, classification linkage, and legal basis assignment per data category.

Art. 30 Required Content for Controllers — Art. 30(1)

Required Field	Description	Classification Relevance
(a) Controller identity	Name and contact details of controller, joint controller, representative, DPO	Administrative — not classification-dependent
(b) Purposes of processing	Specific purpose for each processing activity	Purpose determines applicable lawful basis and drives classification-to-handling mapping
(c) Categories of data subjects	Types of individuals whose data is processed (customers, employees, applicants)	Data subject category affects applicable protections (e.g., children, employees)
(d) Categories of personal data	Types of personal data processed per activity	Direct output of data classification — personal, special category, criminal
(e) Categories of recipients	Who receives the data, including processors	Determines transfer and sharing controls
(f) Transfers to third countries	International transfers and safeguard mechanisms	Triggers Chapter V compliance requirements
(g) Retention periods	Envisaged time limits for erasure of different categories	Classification tier drives retention policy
(h) Security measures	General description of Art. 32 technical and organisational measures	Classification tier determines security control level

Data Inventory Construction Methodology

Phase 1: System Discovery (Weeks 1-3)

Step 1: Enterprise Application Inventory

Build a complete list of systems that process personal data:

Discovery Method	Sources	Output
IT asset management system	CMDB, ServiceNow, Lansweeper	Registered applications and servers
Procurement records	Vendor contracts, SaaS subscriptions, licence management	Third-party systems processing data
Network traffic analysis	Firewall logs, proxy logs, DNS queries	Undocumented data flows to external services
Shadow IT discovery	Cloud access security broker (CASB) logs, expense reports for SaaS tools	Unauthorised or unknown applications
Department interviews	Business unit leads, data stewards	Departmental tools and local databases

Vanguard Financial Services — System Inventory Example

System	Type	Department	Data Subjects	Classification Priority
Salesforce CRM	SaaS	Sales, Customer Service	Customers, prospects	Tier 1
Workday HR	SaaS	Human Resources	Employees, candidates	Tier 1
ADP GlobalView	SaaS	Payroll	Employees	Tier 1
Oracle Data Warehouse	On-premises	Data Engineering	All subjects	Tier 1
SharePoint Online	SaaS	All departments	All subjects	Tier 1
NICE Actimize	On-premises	Compliance	Customers, counterparties	Tier 1
HID Global Access	On-premises	Facilities	Employees, contractors	Tier 2
Cority Occ Health	SaaS	Occupational Health	Employees	Tier 2
Bloomberg Terminal	SaaS	Trading	Counterparties	Tier 2
Microsoft Teams	SaaS	All departments	Employees, external contacts	Tier 2
Adobe Analytics	SaaS	Marketing	Website visitors	Tier 2
ServiceNow ITSM	SaaS	IT	Employees	Tier 3
Confluence Wiki	SaaS	Engineering	Employees	Tier 3

Phase 2: Data Element Mapping (Weeks 3-6)

For each system, document every data element:

Step 2: Schema Extraction

• Structured databases: Extract schema metadata (table names, column names, data types) via SQL metadata queries or data catalogue APIs
• SaaS applications: Use API documentation to enumerate data objects and fields
• Unstructured repositories: Catalogue document types and their typical personal data content
• Automated discovery: Deploy scanning tools to identify PII in all repositories (see auto-data-discovery skill)

Step 3: Data Element Classification

For each data element, assign:

• Personal data classification: PERSONAL_DIRECT, PERSONAL_INDIRECT, SPECIAL_CATEGORY, CRIMINAL_ART10, PSEUDONYMISED, ANONYMISED, NON_PERSONAL (see personal-data-test skill)
• Classification tier: Public, Internal, Confidential, Restricted (see classification-policy skill)
• Art. 6 lawful basis: The legal basis for processing this element for each stated purpose
• Art. 9(2) condition: If special category, the specific processing condition

Phase 3: Data Flow Mapping (Weeks 6-9)

Step 4: Intra-System Data Flows

Document how data moves within the organisation:

Customer Onboarding Data Flow — Vanguard Financial Services

Customer ──[web form]──► Salesforce CRM
                              │
                    ┌─────────┼──────────┐
                    ▼         ▼          ▼
              Oracle DW   SharePoint   Email (welcome)
              (analytics) (documents)  (notifications)
                    │
                    ▼
              Adobe Analytics
              (web behaviour)

Step 5: External Data Flows (Third-Party Sharing)

Document all data sharing with external parties:

Sender System	Recipient	Data Categories	Transfer Mechanism	Legal Safeguard
Salesforce CRM	Salesforce Inc. (processor)	Customer personal data	SaaS hosting	Standard Contractual Clauses (2021/914)
Workday HR	Workday Inc. (processor)	Employee personal + special category	SaaS hosting	EU-US Data Privacy Framework
ADP Payroll	HMRC (statutory recipient)	Employee financial data	Secure file transfer	Legal obligation Art. 6(1)(c)
NICE Actimize	NCA (statutory recipient)	Customer AML data (Art. 10)	SAR Online portal	Legal obligation POCA 2002
Oracle DW	Deloitte (auditor)	Anonymised financial data	Encrypted file transfer	Joint controller agreement

Phase 4: Legal Basis and Purpose Mapping (Weeks 9-11)

Step 6: Purpose-Basis Matrix

For each processing activity, map data categories to purposes and legal bases:

Processing Activity	Data Category	Purpose	Art. 6 Basis	Art. 9(2) / Art. 10
Customer account management	Name, email, address, account number	Contract performance	Art. 6(1)(b)	N/A
KYC identity verification	Name, DOB, ID documents, address	Legal obligation (MLR 2017)	Art. 6(1)(c)	N/A
Employee payroll	Name, NINO, bank details, salary	Contract performance	Art. 6(1)(b)	N/A
Employee diversity monitoring	Ethnicity, sexual orientation	Equality monitoring	Art. 6(1)(a) / 6(1)(c)	Art. 9(2)(a) / 9(2)(b)
Building access control	Fingerprint template	Physical security	Art. 6(1)(f)	Art. 9(2)(a)
AML monitoring	Transaction patterns, SAR data	Legal obligation (POCA 2002)	Art. 6(1)(c)	Art. 10 — DPA Sch.1 Pt.2 para 10
Website analytics	IP address, cookies, browsing	Legitimate interests	Art. 6(1)(f)	N/A
Marketing communications	Email, preferences	Consent	Art. 6(1)(a)	N/A

Phase 5: Documentation and Maintenance (Ongoing)

Step 7: Inventory Consolidation

Consolidate all discovery into the formal data inventory:

• One record per data element per system
• Cross-referenced to processing activities in the RoPA
• Classification labels applied per element
• Review dates set per classification tier

Step 8: Ongoing Maintenance

Maintenance Activity	Frequency	Responsible
Automated discovery scan reconciliation	Monthly	Privacy Engineering
New system onboarding inventory	Per new system deployment	System Owner + Privacy Analyst
Department data steward review	Quarterly	Data Stewards
Full inventory accuracy audit	Annually	DPO
Classification reclassification review	Annually (borderline: 6-monthly)	Privacy Analyst

Data Flow Diagram Standards

Notation Convention (Based on DFD Level 0/1)

Symbol	Meaning
Rectangle	External entity (data subject, third party, regulator)
Rounded rectangle	Process (system or application)
Open rectangle (two parallel lines)	Data store (database, file share)
Arrow	Data flow (labelled with data categories)
Dashed arrow	Optional or conditional data flow
Red border	Contains special category or criminal data
Blue border	International transfer

Enforcement Precedents

• Österreichische Datenschutzbehörde (Austrian DPA) v Local Bakery Chain (2020): EUR 4,000 fine for failure to maintain Art. 30 records. The DPA noted that even small organisations must maintain processing records.
• CNIL v Sergic (2019): EUR 400,000 fine, partly for inadequate data mapping — the controller could not demonstrate it knew where personal data was stored, leading to a data breach going undetected.
• ICO v British Airways (2020): GBP 20 million fine, where inadequate data mapping contributed to delayed breach detection — the controller lacked visibility into personal data flows through its web infrastructure.

Integration Points

• auto-data-discovery: Automated scanning feeds data elements into the inventory
• personal-data-test: Classification decisions applied per data element in the inventory
• special-category-data: Art. 9 data flagged and mapped to processing conditions
• criminal-data-handling: Art. 10 data identified and mapped to national law authorisation
• data-lineage-tracking: Lineage graphs extend the static inventory with dynamic flow information