Migrations minangka cara Django kanggo nyebaring owah-owahan sing kowe gawe ing models mu (nambah field, nggawa model) menyang database schema — iki version-controlled, nganggo database change files sing dijenerake kanthi otomatis. Kowe ngowah models ing Python; migrations nglokalisir database supaya tetep selaras.
python manage.py makemigrations
python manage.py migrate
makemigrations ndeteksi owah-owahan model lan ngajenerake file migration; migrate nerapake migrations sing isih pending menyang database nyata. Kowe nulis Python (owah-owahan model), lan Django ngajenerake lan njalanake SQL.
# migrations/0002_article_views.py (auto-generated)
class Migration(migrations.Migration):
dependencies = [("blog", "0001_initial")] # ordering — depends on the previous one
operations = [
migrations.AddField( # the change
model_name="article",
name="views",
field=models.IntegerField(default=0),
),
]
Migrations commit menyang version control, dadi riwayat database schema ditelusuri sadangsa karo code. Saben pengembang lan environment nerapake migrations sing padha kanggo raih schema sing padha — bisa diulang lan konsisten.
✓ Schema changes are version-controlled (tracked with the code, reviewable in PRs)
✓ Reproducible — every dev/staging/production DB gets the same schema by running migrate
✓ No manual, error-prone SQL — Django generates the correct ALTER statements
✓ Reversible — many migrations can be rolled back (migrate <app> <previous>)
✓ Team-friendly — schema changes flow through the normal code-review process
python manage.py showmigrations # see which migrations are applied/pending
python manage.py sqlmigrate blog 0002 # preview the SQL a migration will run
python manage.py makemigrations --empty # a blank migration for custom/data changes
python manage.py migrate blog 0001 # roll BACK to a previous migration
Migrations can also transform DATA (e.g. populate a new field, backfill values)
via RunPython operations — useful when a schema change needs accompanying data changes.
Migrations iku penting kanggo makarya karo Django database layer — iki ngatasi masalah kritis yaiku nglokalisir database schema supaya tetep selaras karo Python models mu kanthi aman, bisa diulang, lan akrab karo tim.
Ngerti babagan iki minangka ilmu dasar saben dina: workflow makemigrations → migrate iku carane saben owah-owahan schema kadadean (kowe ngowah models, Django ngajenerake lan nerapake SQL), dadi kowe ora bisa ngembangake Django app sing data-driven tanpa iki.
Nilai utama iku migrations nggaweke owah-owahan schema version-controlled (ditelusuri sadangsa karo code, bisa direwiu ing pull requests), bisa diulang (saben environment — mesin saben pengembang, staging, production — raih schema sing identical kanthi njalanake migrations sing padha), lan aman (Django ngajenerake SQL sing bener, asring bisa dibalik tinimbang statement ALTER TABLE manual sing gampang salah).
Iki ngilangi kategori masalah lengkap babagan schema drift, environments sing ora konsisten, lan owah-owahan database manual sing berisiko.
Ngerti workflow, yen migrations di-commit menyang source control, kepiye carane nimpeni lan ngbalik migrations, lan yen iku bisa ugo ngatasi data transformations (backfilling/migrasi data, ora mung schema) iku perlu kanggo proyek Django sing nyata.
Migrations minangka carane Django teams ngembangake database schema kanthi kolaboratif lan bisa dipercaya sajrone urip proyek, nggaweke materi inti sing kudu diweruhi.