Equipment Lease Management — Semantic Model

1. Overview

A lessee-side system for tracking equipment lease contracts with vendors, the individual assets they cover, the planned and actual payment streams they generate, and the budgets against which those payments are measured. Users are finance analysts, contract owners, and cost-center managers who need to answer questions like “what is our total lease obligation next quarter?”, “which contracts are over budget?”, and “which assets are still under lease and where are they deployed?”. The data model is platform-agnostic; budgeting is modeled at the cost-center / fiscal-period grain so variance analysis against actual payments is straightforward downstream.

2. Entity summary

#	Table name	Singular label	Purpose
1	vendors	Vendor	Lessor companies the organization leases equipment from
2	equipment_categories	Equipment Category	Classification of leased equipment (IT hardware, vehicles, copiers, machinery)
3	locations	Location	Physical sites where leased equipment is deployed
4	cost_centers	Cost Center	Internal org units (departments, projects) to which lease costs are charged
5	users	User	Employees who own, approve, or administer lease contracts
6	lease_contracts	Lease Contract	Master legal agreement with a vendor covering one or more leased assets
7	leased_assets	Leased Asset	Individual piece of equipment covered by a lease contract
8	payment_schedules	Payment Schedule	Planned periodic payment obligation generated from contract terms
9	lease_payments	Lease Payment	Actual payment posted/invoiced against a scheduled obligation
10	fiscal_periods	Fiscal Period	Budget calendar unit (fiscal month, quarter, or year)
11	budget_lines	Budget Line	Planned lease spend for a cost center in a fiscal period (optionally per category)

Entity-relationship diagram

flowchart LR
    vendors -->|leases to| lease_contracts
    cost_centers -->|funds| lease_contracts
    users -->|owns| lease_contracts
    lease_contracts -->|covers| leased_assets
    equipment_categories -->|classifies| leased_assets
    locations -->|houses| leased_assets
    users -->|assigned| leased_assets
    lease_contracts -->|generates| payment_schedules
    fiscal_periods -->|contains| payment_schedules
    payment_schedules -->|settled by| lease_payments
    users -->|approves| lease_payments
    users -->|manages| locations
    users -->|manages| cost_centers
    cost_centers -->|plans| budget_lines
    fiscal_periods -->|spans| budget_lines
    equipment_categories -->|slices| budget_lines
    users -->|approves| budget_lines

3. Entities

3.1 vendors — Vendor

Plural label: Vendors Label column: vendor_name Description: A lessor company from which the organization rents equipment. One vendor can be counterparty to many lease contracts over time.

Fields

Field name	Format	Required	Label	Reference / Notes
vendor_name	string	yes	Vendor Name	label_column
vendor_code	string	no	Vendor Code	unique, short internal code
contact_email	email	no	Contact Email
contact_phone	string	no	Contact Phone
website	url	no	Website
address_line	string	no	Address
city	string	no	City
country	string	no	Country	ISO 3166 alpha-2 suggested
vendor_status	enum	yes	Status	values: active, inactive
notes	text	no	Notes

Relationships

• A vendor is the counterparty for many lease_contracts (1:N, via lease_contracts.vendor_id, restrict on delete).

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3.2 equipment_categories — Equipment Category

Plural label: Equipment Categories Label column: category_name Description: A classification bucket for leased equipment (e.g. IT Hardware, Vehicles, Copiers, Machinery). Used for slicing budgets and reporting.

Fields

Field name	Format	Required	Label	Reference / Notes
category_name	string	yes	Category Name	label_column, unique
description	text	no	Description

Relationships

• An equipment_category classifies many leased_assets (1:N, via leased_assets.equipment_category_id, restrict on delete).
• An equipment_category optionally slices many budget_lines (1:N, via budget_lines.equipment_category_id, clear on delete).

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3.3 locations — Location

Plural label: Locations Label column: location_name Description: A physical site (office, warehouse, field location) where leased equipment is deployed. Enables asset-location reporting and physical inventory reconciliation.

Fields

Field name	Format	Required	Label	Reference / Notes
location_name	string	yes	Location Name	label_column
location_code	string	no	Location Code	unique
address_line	string	no	Address
city	string	no	City
state_region	string	no	State/Region
postal_code	string	no	Postal Code
country	string	no	Country
site_manager_id	reference	no	Site Manager	→ users (N:1), clear on delete

Relationships

• A location is managed by at most one user (N:1, optional, clear on delete).
• A location houses many leased_assets (1:N, via leased_assets.location_id, clear on delete).

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3.4 cost_centers — Cost Center

Plural label: Cost Centers Label column: cost_center_name Description: An internal organizational unit (department, project, business unit) against which lease costs are charged and budgets are planned. Every lease contract is funded by exactly one cost center (primary allocation).

Fields

Field name	Format	Required	Label	Reference / Notes
cost_center_name	string	yes	Cost Center Name	label_column
cost_center_code	string	yes	Cost Center Code	unique
department	string	no	Department
description	text	no	Description
manager_id	reference	no	Manager	→ users (N:1), clear on delete
cost_center_status	enum	yes	Status	values: active, inactive

Relationships

• A cost_center is managed by at most one user (N:1, optional, clear on delete).
• A cost_center funds many lease_contracts (1:N, via lease_contracts.primary_cost_center_id, restrict on delete).
• A cost_center plans many budget_lines (1:N, via budget_lines.cost_center_id, restrict on delete).

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3.5 users — User

Plural label: Users Label column: full_name Description: An employee who owns, approves, or administers lease contracts, assets, payments, or budgets. Included for model completeness; the deployer will deduplicate against the Semantius built-in users table at implementation time.

Fields

Field name	Format	Required	Label	Reference / Notes
full_name	string	yes	Full Name	label_column
email	email	yes	Email	unique
employee_id	string	no	Employee ID	unique
department	string	no	Department
user_status	enum	yes	Status	values: active, inactive

Relationships

• A user may manage many locations (1:N, via locations.site_manager_id, clear).
• A user may manage many cost_centers (1:N, via cost_centers.manager_id, clear).
• A user may own many lease_contracts (1:N, via lease_contracts.contract_owner_id, restrict).
• A user may have many leased_assets deployed to them (1:N, via leased_assets.deployed_to_user_id, clear).
• A user may approve many lease_payments (1:N, via lease_payments.approved_by_user_id, clear).
• A user may approve many budget_lines (1:N, via budget_lines.approved_by_user_id, clear).

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3.6 lease_contracts — Lease Contract

Plural label: Lease Contracts Label column: contract_number Description: The master legal agreement with a vendor covering one or more leased assets, with a fixed term, payment schedule, and commercial terms. One contract generates many payment schedules and owns many leased assets.

Fields

Field name	Format	Required	Label	Reference / Notes
contract_number	string	yes	Contract Number	label_column, unique, e.g. LC-2026-0042
contract_title	string	no	Title	human description, e.g. “IT fleet refresh 2026”
vendor_id	reference	yes	Vendor	→ vendors (N:1), restrict
primary_cost_center_id	reference	yes	Cost Center	→ cost_centers (N:1), restrict
contract_owner_id	reference	yes	Contract Owner	→ users (N:1), restrict
contract_status	enum	yes	Status	values: draft, active, expired, terminated, renewed
lease_type	enum	yes	Lease Type	values: operating, finance, short_term (ASC 842 classification)
commencement_date	date	yes	Commencement Date
end_date	date	yes	End Date
term_months	integer	yes	Term (Months)
currency_code	string	yes	Currency	ISO 4217, e.g. USD
monthly_payment_amount	float	no	Monthly Payment	base monthly rent
total_contract_value	float	no	Total Contract Value	sum of all scheduled payments over the term
payment_frequency	enum	yes	Payment Frequency	values: monthly, quarterly, semi_annual, annual
auto_renewal	boolean	yes	Auto Renewal
renewal_notice_days	integer	no	Renewal Notice (Days)	days before end_date required to opt out
signed_date	date	no	Signed Date
notes	text	no	Notes

Relationships

• A lease_contract is with one vendor (N:1, required, restrict).
• A lease_contract is funded by one cost_center (N:1, required, restrict).
• A lease_contract is owned by one user (N:1, required, restrict).
• A lease_contract covers many leased_assets (1:N, ownership, cascade on delete).
• A lease_contract generates many payment_schedules (1:N, ownership, cascade on delete).

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3.7 leased_assets — Leased Asset

Plural label: Leased Assets Label column: asset_tag Description: An individual piece of equipment covered by a lease contract, with a serial number and deployed location. Created in the context of a contract and cascaded-deleted when the contract is removed.

Fields

Field name	Format	Required	Label	Reference / Notes
asset_tag	string	yes	Asset Tag	label_column, unique
asset_description	string	yes	Description
lease_contract_id	parent	yes	Lease Contract	↳ lease_contracts (N:1, cascade)
equipment_category_id	reference	yes	Category	→ equipment_categories (N:1), restrict
location_id	reference	no	Location	→ locations (N:1), clear
manufacturer	string	no	Manufacturer
model	string	no	Model
serial_number	string	no	Serial Number	unique
acquisition_cost	float	no	Acquisition Cost	fair value at lease start (ROU asset basis)
monthly_rent_amount	float	no	Monthly Rent	asset’s share of contract payment
condition_status	enum	yes	Condition	values: new, good, fair, poor, retired
deployed_to_user_id	reference	no	Deployed To	→ users (N:1), clear
decommission_date	date	no	Decommission Date
notes	text	no	Notes

Relationships

• A leased_asset belongs to one lease_contract (N:1, required, cascade on delete).
• A leased_asset is classified as one equipment_category (N:1, required, restrict).
• A leased_asset may be housed at one location (N:1, optional, clear).
• A leased_asset may be deployed to one user (N:1, optional, clear).

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3.8 payment_schedules — Payment Schedule

Plural label: Payment Schedules Label column: schedule_reference Description: A planned periodic payment obligation generated from a lease contract’s terms. The set of schedules for a contract represents the full planned cash-out over the lease term. Each schedule row is settled by zero or more actual lease payments.

Fields

Field name	Format	Required	Label	Reference / Notes
schedule_reference	string	yes	Schedule Reference	label_column — caller populates, e.g. LC-2026-0042 / 2026-03
lease_contract_id	parent	yes	Lease Contract	↳ lease_contracts (N:1, cascade)
fiscal_period_id	reference	no	Fiscal Period	→ fiscal_periods (N:1), clear
payment_number	integer	yes	Payment #	1-based sequence within the contract
scheduled_date	date	yes	Scheduled Date
scheduled_amount	float	yes	Scheduled Amount
currency_code	string	yes	Currency	ISO 4217
schedule_status	enum	yes	Status	values: pending, invoiced, paid, overdue, waived
notes	text	no	Notes

Relationships

• A payment_schedule belongs to one lease_contract (N:1, required, cascade on delete).
• A payment_schedule may fall in one fiscal_period (N:1, optional, clear).
• A payment_schedule is settled by many lease_payments (1:N, via lease_payments.payment_schedule_id, restrict on delete).

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3.9 lease_payments — Lease Payment

Plural label: Lease Payments Label column: payment_reference Description: An actual payment posted or invoiced against a scheduled obligation. Used to compute actual-vs-planned variance and to track settlement of the contract’s cash schedule.

Fields

Field name	Format	Required	Label	Reference / Notes
payment_reference	string	yes	Payment Reference	label_column, unique, e.g. voucher or AP posting number
payment_schedule_id	reference	yes	Payment Schedule	→ payment_schedules (N:1), restrict
payment_date	date	yes	Payment Date	actual posting date
payment_amount	float	yes	Amount
currency_code	string	yes	Currency	ISO 4217
payment_method	enum	yes	Payment Method	values: ach, wire, check, credit_card, other
invoice_number	string	no	Invoice Number	vendor invoice number
approved_by_user_id	reference	no	Approved By	→ users (N:1), clear
notes	text	no	Notes

Relationships

• A lease_payment settles one payment_schedule (N:1, required, restrict on delete of the schedule).
• A lease_payment may be approved by one user (N:1, optional, clear).

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3.10 fiscal_periods — Fiscal Period

Plural label: Fiscal Periods Label column: period_name Description: A budget-calendar unit — a fiscal month, quarter, half-year, or year. Budget lines and payment schedules are assigned to fiscal periods to enable period-level roll-ups and variance analysis.

Fields

Field name	Format	Required	Label	Reference / Notes
period_name	string	yes	Period Name	label_column, unique, e.g. 2026-Q1, 2026-03
period_type	enum	yes	Period Type	values: month, quarter, half_year, year
fiscal_year	integer	yes	Fiscal Year
start_date	date	yes	Start Date
end_date	date	yes	End Date
is_closed	boolean	yes	Closed	when true, blocks further edits to budget_lines assigned to this period (enforced in application logic)

Relationships

• A fiscal_period contains many payment_schedules (1:N, via payment_schedules.fiscal_period_id, clear).
• A fiscal_period spans many budget_lines (1:N, via budget_lines.fiscal_period_id, restrict).

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3.11 budget_lines — Budget Line

Plural label: Budget Lines Label column: budget_line_label Description: Planned lease spend for a cost center in a fiscal period, optionally broken down by equipment category. The plan-side input to variance reporting against actual lease payments.

Fields

Field name	Format	Required	Label	Reference / Notes
budget_line_label	string	yes	Budget Line	label_column — caller populates, e.g. CC-100 / 2026-Q1 / IT hardware
cost_center_id	reference	yes	Cost Center	→ cost_centers (N:1), restrict
fiscal_period_id	reference	yes	Fiscal Period	→ fiscal_periods (N:1), restrict
equipment_category_id	reference	no	Category	→ equipment_categories (N:1), clear — optional category slice
planned_amount	float	yes	Planned Amount
currency_code	string	yes	Currency	ISO 4217
budget_status	enum	yes	Status	values: draft, approved, locked
approved_by_user_id	reference	no	Approved By	→ users (N:1), clear
approved_at	date-time	no	Approved At
notes	text	no	Notes

Relationships

• A budget_line is planned against one cost_center (N:1, required, restrict).
• A budget_line spans one fiscal_period (N:1, required, restrict).
• A budget_line may be sliced by one equipment_category (N:1, optional, clear).
• A budget_line may be approved by one user (N:1, optional, clear).

Uniqueness note: the tuple (cost_center_id, fiscal_period_id, equipment_category_id) should be unique at the app layer. Semantius does not support composite unique constraints declaratively — the implementer must enforce this in application logic or via a database trigger. Tracked in §6.2.

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4. Relationship summary

From	Field	To	Cardinality	Kind	Delete behavior
locations	site_manager_id	users	N:1	reference	clear
cost_centers	manager_id	users	N:1	reference	clear
lease_contracts	vendor_id	vendors	N:1	reference	restrict
lease_contracts	primary_cost_center_id	cost_centers	N:1	reference	restrict
lease_contracts	contract_owner_id	users	N:1	reference	restrict
leased_assets	lease_contract_id	lease_contracts	N:1	parent	cascade
leased_assets	equipment_category_id	equipment_categories	N:1	reference	restrict
leased_assets	location_id	locations	N:1	reference	clear
leased_assets	deployed_to_user_id	users	N:1	reference	clear
payment_schedules	lease_contract_id	lease_contracts	N:1	parent	cascade
payment_schedules	fiscal_period_id	fiscal_periods	N:1	reference	clear
lease_payments	payment_schedule_id	payment_schedules	N:1	reference	restrict
lease_payments	approved_by_user_id	users	N:1	reference	clear
budget_lines	cost_center_id	cost_centers	N:1	reference	restrict
budget_lines	fiscal_period_id	fiscal_periods	N:1	reference	restrict
budget_lines	equipment_category_id	equipment_categories	N:1	reference	clear
budget_lines	approved_by_user_id	users	N:1	reference	clear

5. Enumerations

5.1 vendors.vendor_status

• active
• inactive

5.2 cost_centers.cost_center_status

• active
• inactive

5.3 users.user_status

• active
• inactive

5.4 lease_contracts.contract_status

• draft
• active
• expired
• terminated
• renewed

5.5 lease_contracts.lease_type

• operating
• finance
• short_term

5.6 lease_contracts.payment_frequency

• monthly
• quarterly
• semi_annual
• annual

5.7 leased_assets.condition_status

• new
• good
• fair
• poor
• retired

5.8 payment_schedules.schedule_status

• pending
• invoiced
• paid
• overdue
• waived

5.9 lease_payments.payment_method

• ach
• wire
• check
• credit_card
• other

5.10 fiscal_periods.period_type

• month
• quarter
• half_year
• year

5.11 budget_lines.budget_status

• draft
• approved
• locked

6. Open questions

6.1 🔴 Decisions needed (blockers)

None.

6.2 🟡 Future considerations (deferred scope)

• Should a cost_allocations junction entity be introduced to split a single lease contract’s cost across multiple cost centers on a percentage basis, replacing the current single primary_cost_center_id field on lease_contracts?
• Should lease modifications (ASC 842 remeasurement events — term extensions, payment changes, scope changes) be tracked as their own lease_amendments entity, or left to the audit log of lease_contracts?
• Should scanned contract PDFs, amendments, and supporting documents be tracked as a contract_documents entity with polymorphic links to lease_contracts and leased_assets?
• Should an asset-level cost-center override (leased_assets.cost_center_id) be introduced for cases where one asset on a shared contract is charged to a different cost center than the contract’s primary?
• Should multi-currency handling gain explicit FX-rate snapshots and reporting-currency conversions, or is the current per-row currency_code string sufficient?
• Should cost_centers and equipment_categories support parent-child hierarchies for drill-down reporting, rather than the current flat structure?
• Should renewal options and purchase options on a contract be modeled as their own contract_options entity with exercise/expiry fields, rather than the current auto_renewal / renewal_notice_days scalars?
• Should the composite uniqueness on budget_lines (cost_center_id, fiscal_period_id, equipment_category_id) be enforced by a database-level trigger or unique index, rather than only in application logic?
• Should approval workflows (multi-step sign-off) on lease_contracts and budget_lines be modeled as their own approval-routing entities, rather than the single approved_by_user_id / approved_at pair?

7. Implementation notes for the downstream agent

1. Create one module named lease_management and two baseline permissions (lease_management:read, lease_management:manage) before any entity.
2. Create entities in the order given in §2 — vendors, equipment_categories, locations, cost_centers, users, then lease_contracts, leased_assets, payment_schedules, lease_payments, fiscal_periods, budget_lines — so that every reference_table target already exists when each entity is created. Note: users has FK dependencies on it from locations and cost_centers, so if those are created first, their site_manager_id / manager_id fields must be added after users exists — create the fields in a second pass, or create users first and add its (non-FK) fields.
3. For each entity: set label_column to the snake_case field marked as label in §3, pass module_id, view_permission, edit_permission. Do not manually create id, created_at, updated_at, or the auto-label field.
4. For each field in §3: pass table_name, field_name, format, title (the Label column), is_nullable (inverse of Required), and for reference/parent fields also reference_table and a reference_delete_mode consistent with §4.
5. Deduplicate against Semantius built-in tables. This model is self-contained and declares users, which already exists in Semantius as a built-in. Read Semantius first: if the built-in users covers the domain needs, skip the create and reuse the built-in as the reference_table target — do not attempt to recreate. Optionally add missing fields (full_name, employee_id, department, user_status) to the built-in users entity only if the built-in does not already provide equivalents (additive, low-risk changes only).
6. payment_schedules.schedule_reference and budget_lines.budget_line_label are caller-populated string labels — no platform auto-population. On record creation, callers should compose a readable value (e.g. "{contract_number} / {period_name}" for schedules; "{cost_center_code} / {period_name} / {category_name}" for budget lines).
7. Enforce composite uniqueness on budget_lines (cost_center_id, fiscal_period_id, equipment_category_id) in application logic until a database-level constraint is added (see §6.2).
8. After creation, spot-check that label_column on each entity resolves to a real string field and that all reference_table targets exist.