versionalchemy package

versionalchemy.init()[source]
Parameters:Session – the session factory class
versionalchemy.is_initialized()[source]

Submodules

versionalchemy.exceptions module

exception versionalchemy.exceptions.LogTableCreationError[source]

Bases: exceptions.Exception

Thrown if an invariant is violated when registering a table for versioning with versionalchemy.

versionalchemy.utils module

class versionalchemy.utils.JSONEncodedDict(*args, **kwargs)[source]

Bases: versionalchemy.utils._JSONEncoded

json_type

alias of dict

class versionalchemy.utils.JSONEncodedList(*args, **kwargs)[source]

Bases: versionalchemy.utils._JSONEncoded

json_type

alias of list

versionalchemy.utils.generate_and_clause(cls, row, cols, use_dirty=True)[source]
Parameters:
  • cls – the sqlalchemy ORM model
  • row – a sqlalchemy ORM model object (must be an instance of cls)
  • cols – an iterable of strings corresponding to column names
  • use_dirty – if True (default) will return the dirty value of the column
Returns:

a sqlalchemy.and_() clause which checks for equality of all columns in cols to the value they contain in row.

For example,

generate_and_clause(cls, ['foo', 'bar'], cols) =

would return

sqlalchemy.and_(cls.foo == row.foo, cls.bar == row.bar)
versionalchemy.utils.generate_where_clause(cls, row, col, use_dirty=True)[source]
Parameters:
  • cls – the sqlalchemy ORM model
  • row – a sqlalchemy ORM model object (must be an instance of cls)
  • col – the column name
  • use_dirty – if True (default) will return the dirty value of the column
Returns:

a sqlalchemy == clause
versionalchemy.utils.get_bind_processor(row, col_name, dialect)[source]

Returns a bind_processor for the given column in the row based on the dialect. If dialect is None or there is no bind_processor, returns the identity function. The return value of this can be applied to getattr(row, col_name) and will return the sql type of that value.

versionalchemy.utils.get_column_attribute(row, col_name, use_dirty=True, dialect=None)[source]
Parameters:
  • row – the row object
  • col_name – the column name
  • use_dirty – whether to return the dirty value of the column
  • dialect – if not None, should be a Dialect. If specified, this function will process the column attribute into the dialect type before returning it; useful if one is using user defined column types in their mappers.
Returns:

if use_dirty, this will return the value of col_name on the row before it was changed; else this will return getattr(row, col_name)
versionalchemy.utils.get_column_keys(table)[source]

Return a generator of names of the python attribute for the table columns.

versionalchemy.utils.get_column_keys_and_names(table)[source]

Return a generator of tuples k, c such that k is the name of the python attribute for the column and c is the name of the column in the sql table.

versionalchemy.utils.get_column_names(table)[source]

Return a generator of names of the name of the column in the sql table.

versionalchemy.utils.get_dialect(session)[source]
versionalchemy.utils.has_constraint(tbl_name, engine, *col_names)[source]
Parameters:
  • tbl_name – a string with the name of the table to check
  • engine – an instance of sa.engine.Engine from which to execute the query
  • col_names – the name of columns which the unique constraint should contain
Return type:

bool
Returns:

True if the given columns are part of a unique constraint on tbl_name
versionalchemy.utils.is_modified(row, ignore=None)[source]
versionalchemy.utils.result_to_dict(res)[source]
Parameters:res – sqlalchemy.engine.ResultProxy
Returns:a list of dicts where each dict represents a row in the query where the key is the column name and the value is the value of that column.