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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))
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