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| """Peewee migrations -- 002_add_local_sharing.py. | |
| Some examples (model - class or model name):: | |
| > Model = migrator.orm['table_name'] # Return model in current state by name | |
| > Model = migrator.ModelClass # Return model in current state by name | |
| > migrator.sql(sql) # Run custom SQL | |
| > migrator.run(func, *args, **kwargs) # Run python function with the given args | |
| > migrator.create_model(Model) # Create a model (could be used as decorator) | |
| > migrator.remove_model(model, cascade=True) # Remove a model | |
| > migrator.add_fields(model, **fields) # Add fields to a model | |
| > migrator.change_fields(model, **fields) # Change fields | |
| > migrator.remove_fields(model, *field_names, cascade=True) | |
| > migrator.rename_field(model, old_field_name, new_field_name) | |
| > migrator.rename_table(model, new_table_name) | |
| > migrator.add_index(model, *col_names, unique=False) | |
| > migrator.add_not_null(model, *field_names) | |
| > migrator.add_default(model, field_name, default) | |
| > migrator.add_constraint(model, name, sql) | |
| > migrator.drop_index(model, *col_names) | |
| > migrator.drop_not_null(model, *field_names) | |
| > migrator.drop_constraints(model, *constraints) | |
| """ | |
| from contextlib import suppress | |
| import peewee as pw | |
| from peewee_migrate import Migrator | |
| with suppress(ImportError): | |
| import playhouse.postgres_ext as pw_pext | |
| def migrate(migrator: Migrator, database: pw.Database, *, fake=False): | |
| """Write your migrations here.""" | |
| if isinstance(database, pw.SqliteDatabase): | |
| migrate_sqlite(migrator, database, fake=fake) | |
| else: | |
| migrate_external(migrator, database, fake=fake) | |
| def migrate_sqlite(migrator: Migrator, database: pw.Database, *, fake=False): | |
| # Adding fields created_at and updated_at to the 'chat' table | |
| migrator.add_fields( | |
| "chat", | |
| created_at=pw.DateTimeField(null=True), # Allow null for transition | |
| updated_at=pw.DateTimeField(null=True), # Allow null for transition | |
| ) | |
| # Populate the new fields from an existing 'timestamp' field | |
| migrator.sql( | |
| "UPDATE chat SET created_at = timestamp, updated_at = timestamp WHERE timestamp IS NOT NULL" | |
| ) | |
| # Now that the data has been copied, remove the original 'timestamp' field | |
| migrator.remove_fields("chat", "timestamp") | |
| # Update the fields to be not null now that they are populated | |
| migrator.change_fields( | |
| "chat", | |
| created_at=pw.DateTimeField(null=False), | |
| updated_at=pw.DateTimeField(null=False), | |
| ) | |
| def migrate_external(migrator: Migrator, database: pw.Database, *, fake=False): | |
| # Adding fields created_at and updated_at to the 'chat' table | |
| migrator.add_fields( | |
| "chat", | |
| created_at=pw.BigIntegerField(null=True), # Allow null for transition | |
| updated_at=pw.BigIntegerField(null=True), # Allow null for transition | |
| ) | |
| # Populate the new fields from an existing 'timestamp' field | |
| migrator.sql( | |
| "UPDATE chat SET created_at = timestamp, updated_at = timestamp WHERE timestamp IS NOT NULL" | |
| ) | |
| # Now that the data has been copied, remove the original 'timestamp' field | |
| migrator.remove_fields("chat", "timestamp") | |
| # Update the fields to be not null now that they are populated | |
| migrator.change_fields( | |
| "chat", | |
| created_at=pw.BigIntegerField(null=False), | |
| updated_at=pw.BigIntegerField(null=False), | |
| ) | |
| def rollback(migrator: Migrator, database: pw.Database, *, fake=False): | |
| """Write your rollback migrations here.""" | |
| if isinstance(database, pw.SqliteDatabase): | |
| rollback_sqlite(migrator, database, fake=fake) | |
| else: | |
| rollback_external(migrator, database, fake=fake) | |
| def rollback_sqlite(migrator: Migrator, database: pw.Database, *, fake=False): | |
| # Recreate the timestamp field initially allowing null values for safe transition | |
| migrator.add_fields("chat", timestamp=pw.DateTimeField(null=True)) | |
| # Copy the earliest created_at date back into the new timestamp field | |
| # This assumes created_at was originally a copy of timestamp | |
| migrator.sql("UPDATE chat SET timestamp = created_at") | |
| # Remove the created_at and updated_at fields | |
| migrator.remove_fields("chat", "created_at", "updated_at") | |
| # Finally, alter the timestamp field to not allow nulls if that was the original setting | |
| migrator.change_fields("chat", timestamp=pw.DateTimeField(null=False)) | |
| def rollback_external(migrator: Migrator, database: pw.Database, *, fake=False): | |
| # Recreate the timestamp field initially allowing null values for safe transition | |
| migrator.add_fields("chat", timestamp=pw.BigIntegerField(null=True)) | |
| # Copy the earliest created_at date back into the new timestamp field | |
| # This assumes created_at was originally a copy of timestamp | |
| migrator.sql("UPDATE chat SET timestamp = created_at") | |
| # Remove the created_at and updated_at fields | |
| migrator.remove_fields("chat", "created_at", "updated_at") | |
| # Finally, alter the timestamp field to not allow nulls if that was the original setting | |
| migrator.change_fields("chat", timestamp=pw.BigIntegerField(null=False)) | |