diff --git a/backend-old/internal/domain/models.go b/backend-old/internal/domain/models.go
index bc47aed..f66d9b7 100644
--- a/backend-old/internal/domain/models.go
+++ b/backend-old/internal/domain/models.go
@@ -6,9 +6,13 @@ import (
 	"github.com/gofrs/uuid/v5"
 )
 
+// CompanyID and UserID are UUIDv7 identifiers for performance-friendly indexing.
+type CompanyID = uuid.UUID
+type UserID = uuid.UUID
+
 // Tenant represents a B2B actor (pharmacy/distributor) in the marketplace.
 type Tenant struct {
-	ID            uuid.UUID `db:"id" json:"id"`
+	ID            CompanyID `db:"id" json:"id"`
 	CNPJ          string    `db:"cnpj" json:"cnpj"`
 	CorporateName string    `db:"corporate_name" json:"corporate_name"`
 	Category      string    `db:"category" json:"category"` // farmacia, distribuidora
@@ -46,8 +50,8 @@ const (
 
 // User represents an authenticated actor inside a company.
 type User struct {
-	ID            uuid.UUID `db:"id" json:"id"`
-	CompanyID     uuid.UUID `db:"company_id" json:"company_id"`
+	ID            UserID    `db:"id" json:"id"`
+	CompanyID     CompanyID `db:"company_id" json:"company_id"`
 	Role          string    `db:"role" json:"role"`
 	Name          string    `db:"name" json:"name"`
 	Username      string    `db:"username" json:"username"`
@@ -67,7 +71,7 @@ type User struct {
 
 // UserFilter captures listing constraints.
 type UserFilter struct {
-	CompanyID *uuid.UUID
+	CompanyID *CompanyID
 	Limit     int
 	Offset    int
 }
@@ -498,7 +502,7 @@ type Review struct {
 
 // CompanyRating exposes the aggregate score for a seller or pharmacy.
 type CompanyRating struct {
-	CompanyID    uuid.UUID `json:"company_id"`
+	CompanyID    CompanyID `json:"company_id"`
 	AverageScore float64   `json:"average_score"`
 	TotalReviews int64     `json:"total_reviews"`
 }
@@ -530,7 +534,7 @@ type AdminDashboard struct {
 // CompanyDocument represents a KYC/KYB document (CNPJ card, Permit).
 type CompanyDocument struct {
 	ID              uuid.UUID `db:"id" json:"id"`
-	CompanyID       uuid.UUID `db:"company_id" json:"company_id"`
+	CompanyID       CompanyID `db:"company_id" json:"company_id"`
 	Type            string    `db:"type" json:"type"` // CNPJ, PERMIT, IDENTITY
 	URL             string    `db:"url" json:"url"`
 	Status          string    `db:"status" json:"status"` // PENDING, APPROVED, REJECTED
@@ -542,7 +546,7 @@ type CompanyDocument struct {
 // LedgerEntry represents an immutable financial record.
 type LedgerEntry struct {
 	ID          uuid.UUID  `db:"id" json:"id"`
-	CompanyID   uuid.UUID  `db:"company_id" json:"company_id"`
+	CompanyID   CompanyID  `db:"company_id" json:"company_id"`
 	AmountCents int64      `db:"amount_cents" json:"amount_cents"`
 	Type        string     `db:"type" json:"type"` // SALE, FEE, WITHDRAWAL, REFUND
 	Description string     `db:"description" json:"description"`
@@ -553,7 +557,7 @@ type LedgerEntry struct {
 // Withdrawal represents a payout request.
 type Withdrawal struct {
 	ID              uuid.UUID `db:"id" json:"id"`
-	CompanyID       uuid.UUID `db:"company_id" json:"company_id"`
+	CompanyID       CompanyID `db:"company_id" json:"company_id"`
 	AmountCents     int64     `db:"amount_cents" json:"amount_cents"`
 	Status          string    `db:"status" json:"status"` // PENDING, APPROVED, PAID, REJECTED
 	BankAccountInfo string    `db:"bank_account_info" json:"bank_account_info"`
diff --git a/backend-old/internal/repository/postgres/migrations/0001_init.sql b/backend-old/internal/repository/postgres/migrations/0001_init.sql
index df08e3f..93720ad 100644
--- a/backend-old/internal/repository/postgres/migrations/0001_init.sql
+++ b/backend-old/internal/repository/postgres/migrations/0001_init.sql
@@ -16,7 +16,7 @@ CREATE TABLE IF NOT EXISTS companies (
 CREATE TABLE IF NOT EXISTS users (
     id UUID PRIMARY KEY,
     company_id UUID NOT NULL REFERENCES companies(id),
-    role TEXT NOT NULL,
+    role TEXT NOT NULL DEFAULT 'PHARMACY',
     name TEXT NOT NULL,
     email TEXT NOT NULL UNIQUE,
     password_hash TEXT NOT NULL,