versionalchemy.models package

class versionalchemy.models.VALogMixin

Bases: object

A mixin providing the schema for the log table, an append only table which saves old versions of rows. An inheriting model must specify the following columns:

• user_id - a column corresponding to the user that made the specified change
• 1 or more columns which are a subset of columns in the user table. These columns

must have a unique constraint on the user table and also be named the same in both tables

classmethod build_row_dict(ut_row, session, deleted=False, user_id=None, use_dirty=True)

Parameters:

• ut_row – the row from the user table
• deleted – whether or not the row is deleted
• user_id – the user that is performing the update on this row
• use_dirty – whether to use the dirty fields from ut_row or not

Returns:

a dictionary of key value pairs to be inserted into the archive table

Return type:

dict

va_data = Column(None, JSONEncodedDict(), table=None, nullable=False)

va_deleted = Column(None, Boolean(), table=None, nullable=False)

va_id = Column(None, Integer(), table=None, primary_key=True, nullable=False)

va_updated_at = Column(None, DateTime(), table=None, nullable=False)

va_version = Column(None, Integer(), table=None, nullable=False)

class versionalchemy.models.VAModelMixin

Bases: object

classmethod register(ArchiveTable, engine)

Parameters:

• ArchiveTable – the model for the users archive table
• engine – the database engine
• version_col_names – strings which correspond to columns that versioning will pivot around. These columns must have a unique constraint set on them.

updated_by(user)

va_id = Column(None, Integer(), table=None, nullable=False, default=ColumnDefault(0))

va_ignore_columns = None

va_version_columns = None

version(session)

Returns the rows current version. This can only be called after a row has been inserted into the table and the session has been flushed. Otherwise this method has undefined behavior.