E

Sequence Generation Quick Start

Developer guide for the Enezaframework sequence generation. Part of the Sequence Generation series.

Table of Contents

  1. Overview
  2. Step 1 — Define the Model
  3. Step 2 — Define Project Choices (Optional)
  4. Step 3 — Configure Settings
  5. Step 4 — Create the Sequence Configuration
  6. Result
  7. Related Guides

Overview

A sequenced model needs three things: a base model that includes SequenceMixin (EnezaMaster or EnezaDocument), a nullable field to hold the number, and two attributes — sequence_field_name and document_name. The number format itself comes from a SequenceConfig record.

flowchart LR
    A["1. Model<br/>EnezaMaster + attributes"] --> B["2. Project choices<br/>optional"]
    B --> C["3. settings.py<br/>choice paths"]
    C --> D["4. SequenceConfig row<br/>prefix/delimiter/length"]
    D --> E["5. First save -> CUST-0001"]

Step 1 — Define the Model

python
# myapp/models/customer.py
from django.db import models
from enezaframework.models import EnezaMaster
from myapp.choices import ProjectDocumentTypes


class Customer(EnezaMaster):
    customer_code = models.CharField(
        max_length=50,
        null=True,
        blank=True,
        verbose_name="Customer Code",
    )
    name = models.CharField(
        max_length=200,
        verbose_name="Name",
    )
    email = models.EmailField(
        verbose_name="Email",
    )

    sequence_field_name = 'customer_code'
    document_name = ProjectDocumentTypes.CUSTOMER

    class Meta:
        verbose_name = "Customer"
        verbose_name_plural = "Customers"

    def __str__(self):
        return self.customer_code or self.name

Requirements:

  • The sequence field must be nullable (null=True, blank=True) because it is filled on save.
  • sequence_field_name names that field.
  • document_name must equal a value in the active document choices.

Step 2 — Define Project Choices (Optional)

python
# myapp/choices.py
from django.db import models


class ProjectDocumentTypes(models.TextChoices):
    CUSTOMER = 'CUST', "Customer"
    VENDOR = 'VEND', "Vendor"
    INVOICE = 'INV', "Invoice"
    PURCHASE_ORDER = 'PO', "Purchase Order"

If you skip this step, the framework's default NumberSequencesDocument is used. See Sequence Document & Module Choices.

Step 3 — Configure Settings

python
# settings.py
MY_PROJECT_NUMBER_SEQUENCE_DOCUMENT = 'myapp.choices.ProjectDocumentTypes'
MY_PROJECT_MODULES = 'myapp.choices.ProjectModules'

The setting names are MY_PROJECT_NUMBER_SEQUENCE_DOCUMENT and MY_PROJECT_MODULES. Both are optional; when omitted, the framework defaults apply.

Step 4 — Create the Sequence Configuration

In the admin, open System Administrator → Number Sequences and create an active configuration:

Field Value
Document Customer
Prefix CUST
Delimiter -
Number Length 4
Active Yes
Module CRM

See Sequence Admin Setup.

Result

The first Customer save gets CUST-0001, the next CUST-0002, and so on. No value is supplied by the caller — the mixin fills the field when it is empty on a new record.

sequenceDiagram
    actor U as User
    participant C as Customer.save()
    participant M as SequenceMixin
    participant S as SequenceConfig

    U->>C: create customer (customer_code empty)
    C->>M: save()
    M->>S: filter(documents='CUST', active=True).first()
    S-->>M: config(nextnumber=1, number_length=4)
    M->>S: nextnumber = 2; save()
    M->>C: customer_code = 'CUST-0001'
    C-->>U: saved with CUST-0001
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