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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."""
- # 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 rollback(migrator: Migrator, database: pw.Database, *, fake=False):
- """Write your rollback migrations here."""
- # 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))
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