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'Produce an OVER clause against this function. Used against aggregate or so-called "window" functions, for database backends that support window functions. The expression:: func.row_number().over(order_by=\'x\') is shorthand for:: from sqlalchemy import over over(func.row_number(), order_by=\'x\') See :func:`~.expressi...
def over(self, partition_by=None, order_by=None):
return Over(self, partition_by=partition_by, order_by=order_by)
'Produce a :func:`~.expression.select` construct against this :class:`.FunctionElement`. This is shorthand for:: s = select([function_element])'
def select(self):
s = Select([self]) if self._execution_options: s = s.execution_options(**self._execution_options) return s
'Execute this :class:`.FunctionElement` against an embedded \'bind\' and return a scalar value. This first calls :meth:`~.FunctionElement.select` to produce a SELECT construct. Note that :class:`.FunctionElement` can be passed to the :meth:`.Connectable.scalar` method of :class:`.Connection` or :class:`.Engine`.'
def scalar(self):
return self.select().execute().scalar()
'Execute this :class:`.FunctionElement` against an embedded \'bind\'. This first calls :meth:`~.FunctionElement.select` to produce a SELECT construct. Note that :class:`.FunctionElement` can be passed to the :meth:`.Connectable.execute` method of :class:`.Connection` or :class:`.Engine`.'
def execute(self):
return self.select().execute()
'Construct a :class:`.Function`. The :data:`.func` construct is normally used to construct new :class:`.Function` instances.'
def __init__(self, name, *clauses, **kw):
self.packagenames = (kw.pop('packagenames', None) or []) self.name = name self._bind = kw.get('bind', None) self.type = sqltypes.to_instance(kw.get('type_', None)) FunctionElement.__init__(self, *clauses, **kw)
'Initialize the list of child items for this SchemaItem.'
def _init_items(self, *args):
for item in args: if (item is not None): item._set_parent_with_dispatch(self)
'used to allow SchemaVisitor access'
def get_children(self, **kwargs):
return []
'Return the value of the ``quote`` flag passed to this schema object, for those schema items which have a ``name`` field.'
@property @util.deprecated('0.9', 'Use ``<obj>.name.quote``') def quote(self):
return self.name.quote
'Info dictionary associated with the object, allowing user-defined data to be associated with this :class:`.SchemaItem`. The dictionary is automatically generated when first accessed. It can also be specified in the constructor of some objects, such as :class:`.Table` and :class:`.Column`.'
@util.memoized_property def info(self):
return {}
'Return the value of the ``quote_schema`` flag passed to this :class:`.Table`.'
@property @util.deprecated('0.9', 'Use ``table.schema.quote``') def quote_schema(self):
return self.schema.quote
'Return the set of constraints as a list, sorted by creation order.'
@property def _sorted_constraints(self):
return sorted(self.constraints, key=(lambda c: c._creation_order))
'Return the \'key\' for this :class:`.Table`. This value is used as the dictionary key within the :attr:`.MetaData.tables` collection. It is typically the same as that of :attr:`.Table.name` for a table with no :attr:`.Table.schema` set; otherwise it is typically of the form ``schemaname.tablename``.'
@property def key(self):
return _get_table_key(self.name, self.schema)
'Return the connectable associated with this Table.'
@property def bind(self):
return ((self.metadata and self.metadata.bind) or None)
'Add a \'dependency\' for this Table. This is another Table object which must be created first before this one can, or dropped after this one. Usually, dependencies between tables are determined via ForeignKey objects. However, for other situations that create dependencies outside of foreign keys (rules, inheriting),...
def add_is_dependent_on(self, table):
self._extra_dependencies.add(table)
'Append a :class:`~.schema.Column` to this :class:`~.schema.Table`. The "key" of the newly added :class:`~.schema.Column`, i.e. the value of its ``.key`` attribute, will then be available in the ``.c`` collection of this :class:`~.schema.Table`, and the column definition will be included in any CREATE TABLE, SELECT, UP...
def append_column(self, column):
column._set_parent_with_dispatch(self)
'Append a :class:`~.schema.Constraint` to this :class:`~.schema.Table`. This has the effect of the constraint being included in any future CREATE TABLE statement, assuming specific DDL creation events have not been associated with the given :class:`~.schema.Constraint` object. Note that this does **not** produce the co...
def append_constraint(self, constraint):
constraint._set_parent_with_dispatch(self)
'Append a DDL event listener to this ``Table``. .. deprecated:: 0.7 See :class:`.DDLEvents`.'
def append_ddl_listener(self, event_name, listener):
def adapt_listener(target, connection, **kw): listener(event_name, target, connection) event.listen(self, ('' + event_name.replace('-', '_')), adapt_listener)
'Return True if this table exists.'
def exists(self, bind=None):
if (bind is None): bind = _bind_or_error(self) return bind.run_callable(bind.dialect.has_table, self.name, schema=self.schema)
'Issue a ``CREATE`` statement for this :class:`.Table`, using the given :class:`.Connectable` for connectivity. .. seealso:: :meth:`.MetaData.create_all`.'
def create(self, bind=None, checkfirst=False):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
'Issue a ``DROP`` statement for this :class:`.Table`, using the given :class:`.Connectable` for connectivity. .. seealso:: :meth:`.MetaData.drop_all`.'
def drop(self, bind=None, checkfirst=False):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaDropper, self, checkfirst=checkfirst)
'Return a copy of this :class:`.Table` associated with a different :class:`.MetaData`. E.g.:: m1 = MetaData() user = Table(\'user\', m1, Column(\'id\', Integer, priamry_key=True)) m2 = MetaData() user_copy = user.tometadata(m2) :param metadata: Target :class:`.MetaData` object, into which the new :class:`.Table` object...
def tometadata(self, metadata, schema=RETAIN_SCHEMA, referred_schema_fn=None):
if (schema is RETAIN_SCHEMA): schema = self.schema elif (schema is None): schema = metadata.schema key = _get_table_key(self.name, schema) if (key in metadata.tables): util.warn(("Table '%s' already exists within the given MetaData - not copying." % ...
'Construct a new ``Column`` object. :param name: The name of this column as represented in the database. This argument may be the first positional argument, or specified via keyword. Names which contain no upper case characters will be treated as case insensitive names, and will not be quoted unless they are a reserved...
def __init__(self, *args, **kwargs):
name = kwargs.pop('name', None) type_ = kwargs.pop('type_', None) args = list(args) if args: if isinstance(args[0], util.string_types): if (name is not None): raise exc.ArgumentError('May not pass name positionally and as a keyword.') ...
'Return True if this Column references the given column via foreign key.'
def references(self, column):
for fk in self.foreign_keys: if fk.column.proxy_set.intersection(column.proxy_set): return True else: return False
'Create a copy of this ``Column``, unitialized. This is used in ``Table.tometadata``.'
def copy(self, **kw):
args = ([c.copy(**kw) for c in self.constraints] + [c.copy(**kw) for c in self.foreign_keys if (not c.constraint)]) type_ = self.type if isinstance(type_, SchemaEventTarget): type_ = type_.copy(**kw) c = self._constructor(name=self.name, type_=type_, key=self.key, primary_key=self.primary_key, n...
'Create a *proxy* for this column. This is a copy of this ``Column`` referenced by a different parent (such as an alias or select statement). The column should be used only in select scenarios, as its full DDL/default information is not transferred.'
def _make_proxy(self, selectable, name=None, key=None, name_is_truncatable=False, **kw):
fk = [ForeignKey(f.column, _constraint=f.constraint) for f in self.foreign_keys] if ((name is None) and (self.name is None)): raise exc.InvalidRequestError("Cannot initialize a sub-selectable with this Column object until it's 'name' has been assigned.") try: ...
'Construct a column-level FOREIGN KEY. The :class:`.ForeignKey` object when constructed generates a :class:`.ForeignKeyConstraint` which is associated with the parent :class:`.Table` object\'s collection of constraints. :param column: A single target column for the key relationship. A :class:`.Column` object or a colum...
def __init__(self, column, _constraint=None, use_alter=False, name=None, onupdate=None, ondelete=None, deferrable=None, initially=None, link_to_name=False, match=None, **dialect_kw):
self._colspec = column if isinstance(self._colspec, util.string_types): self._table_column = None else: if hasattr(self._colspec, '__clause_element__'): self._table_column = self._colspec.__clause_element__() else: self._table_column = self._colspec if...
'Produce a copy of this :class:`.ForeignKey` object. The new :class:`.ForeignKey` will not be bound to any :class:`.Column`. This method is usually used by the internal copy procedures of :class:`.Column`, :class:`.Table`, and :class:`.MetaData`. :param schema: The returned :class:`.ForeignKey` will reference the origi...
def copy(self, schema=None):
fk = ForeignKey(self._get_colspec(schema=schema), use_alter=self.use_alter, name=self.name, onupdate=self.onupdate, ondelete=self.ondelete, deferrable=self.deferrable, initially=self.initially, link_to_name=self.link_to_name, match=self.match, **self._unvalidated_dialect_kw) return self._schema_item_copy(fk)
'Return a string based \'column specification\' for this :class:`.ForeignKey`. This is usually the equivalent of the string-based "tablename.colname" argument first passed to the object\'s constructor.'
def _get_colspec(self, schema=None):
if schema: (_schema, tname, colname) = self._column_tokens return ('%s.%s.%s' % (schema, tname, colname)) elif (self._table_column is not None): return ('%s.%s' % (self._table_column.table.fullname, self._table_column.key)) else: return self._colspec
'Return True if the given :class:`.Table` is referenced by this :class:`.ForeignKey`.'
def references(self, table):
return (table.corresponding_column(self.column) is not None)
'Return the :class:`.Column` in the given :class:`.Table` referenced by this :class:`.ForeignKey`. Returns None if this :class:`.ForeignKey` does not reference the given :class:`.Table`.'
def get_referent(self, table):
return table.corresponding_column(self.column)
'parse a string-based _colspec into its component parts.'
@util.memoized_property def _column_tokens(self):
m = self._get_colspec().split('.') if (m is None): raise exc.ArgumentError(('Invalid foreign key column specification: %s' % self._colspec)) if (len(m) == 1): tname = m.pop() colname = None else: colname = m.pop() tname = m.pop() if (len(m) > 0)...
'Return the target :class:`.Column` referenced by this :class:`.ForeignKey`. If no target column has been established, an exception is raised. .. versionchanged:: 0.9.0 Foreign key target column resolution now occurs as soon as both the ForeignKey object and the remote Column to which it refers are both associated with...
@util.memoized_property def column(self):
if isinstance(self._colspec, util.string_types): (parenttable, tablekey, colname) = self._resolve_col_tokens() if (tablekey not in parenttable.metadata): raise exc.NoReferencedTableError(("Foreign key associated with column '%s' could not find table '%s' ...
'Return the connectable associated with this default.'
@property def bind(self):
if (getattr(self, 'column', None) is not None): return self.column.table.bind else: return None
'"Construct a new :class:`.ColumnDefault`. :param arg: argument representing the default value. May be one of the following: * a plain non-callable Python value, such as a string, integer, boolean, or other simple type. The default value will be used as is each time. * a SQL expression, that is one which derives from :...
def __init__(self, arg, **kwargs):
super(ColumnDefault, self).__init__(**kwargs) if isinstance(arg, FetchedValue): raise exc.ArgumentError('ColumnDefault may not be a server-side default type.') if util.callable(arg): arg = self._maybe_wrap_callable(arg) self.arg = arg
'Wrap callables that don\'t accept a context. This is to allow easy compatiblity with default callables that aren\'t specific to accepting of a context.'
def _maybe_wrap_callable(self, fn):
try: argspec = util.get_callable_argspec(fn, no_self=True) except TypeError: return (lambda ctx: fn()) defaulted = (((argspec[3] is not None) and len(argspec[3])) or 0) positionals = (len(argspec[0]) - defaulted) if (positionals == 0): return (lambda ctx: fn()) elif (posi...
'Construct a :class:`.Sequence` object. :param name: The name of the sequence. :param start: the starting index of the sequence. This value is used when the CREATE SEQUENCE command is emitted to the database as the value of the "START WITH" clause. If ``None``, the clause is omitted, which on most platforms indicate...
def __init__(self, name, start=None, increment=None, schema=None, optional=False, quote=None, metadata=None, quote_schema=None, for_update=False):
super(Sequence, self).__init__(for_update=for_update) self.name = quoted_name(name, quote) self.start = start self.increment = increment self.optional = optional if ((metadata is not None) and (schema is None) and metadata.schema): self.schema = schema = metadata.schema else: ...
'Return a :class:`.next_value` function element which will render the appropriate increment function for this :class:`.Sequence` within any SQL expression.'
@util.dependencies('sqlalchemy.sql.functions.func') def next_value(self, func):
return func.next_value(self, bind=self.bind)
'Creates this sequence in the database.'
def create(self, bind=None, checkfirst=True):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
'Drops this sequence from the database.'
def drop(self, bind=None, checkfirst=True):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaDropper, self, checkfirst=checkfirst)
'Create a SQL constraint. :param name: Optional, the in-database name of this ``Constraint``. :param deferrable: Optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when issuing DDL for this constraint. :param initially: Optional string. If set, emit INITIALLY <value> when issuing DDL for this constraint. :param...
def __init__(self, name=None, deferrable=None, initially=None, _create_rule=None, **dialect_kw):
self.name = name self.deferrable = deferrable self.initially = initially self._create_rule = _create_rule util.set_creation_order(self) self._validate_dialect_kwargs(dialect_kw)
':param \*columns: A sequence of column names or Column objects. :param name: Optional, the in-database name of this constraint. :param deferrable: Optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when issuing DDL for this constraint. :param initially: Optional string. If set, emit INITIALLY <value> when issu...
def __init__(self, *columns, **kw):
Constraint.__init__(self, **kw) ColumnCollectionMixin.__init__(self, *columns)
'Construct a CHECK constraint. :param sqltext: A string containing the constraint definition, which will be used verbatim, or a SQL expression construct. If given as a string, the object is converted to a :class:`.Text` object. If the textual string includes a colon character, escape this using a backslash:: CheckC...
def __init__(self, sqltext, name=None, deferrable=None, initially=None, table=None, _create_rule=None, _autoattach=True):
super(CheckConstraint, self).__init__(name, deferrable, initially, _create_rule) self.sqltext = _literal_as_text(sqltext) if (table is not None): self._set_parent_with_dispatch(table) elif _autoattach: cols = _find_columns(self.sqltext) tables = set([c.table for c in cols if isin...
'Construct a composite-capable FOREIGN KEY. :param columns: A sequence of local column names. The named columns must be defined and present in the parent Table. The names should match the ``key`` given to each column (defaults to the name) unless ``link_to_name`` is True. :param refcolumns: A sequence of foreign column...
def __init__(self, columns, refcolumns, name=None, onupdate=None, ondelete=None, deferrable=None, initially=None, use_alter=False, link_to_name=False, match=None, table=None, **dialect_kw):
super(ForeignKeyConstraint, self).__init__(name, deferrable, initially, **dialect_kw) self.onupdate = onupdate self.ondelete = ondelete self.link_to_name = link_to_name if ((self.name is None) and use_alter): raise exc.ArgumentError('Alterable Constraint requires a name') sel...
'repopulate this :class:`.PrimaryKeyConstraint` given a set of columns. Existing columns in the table that are marked as primary_key=True are maintained. Also fires a new event. This is basically like putting a whole new :class:`.PrimaryKeyConstraint` object on the parent :class:`.Table` object without actually replaci...
def _reload(self, columns):
for col in columns: col.primary_key = True self.columns.extend(columns) self._set_parent_with_dispatch(self.table)
'Construct an index object. :param name: The name of the index :param \*expressions: Column expressions to include in the index. The expressions are normally instances of :class:`.Column`, but may also be arbitrary SQL expressions which ultmately refer to a :class:`.Column`. :param unique=False: Keyword only argument...
def __init__(self, name, *expressions, **kw):
self.table = None columns = [] for expr in expressions: if (not isinstance(expr, ClauseElement)): columns.append(expr) else: cols = [] visitors.traverse(expr, {}, {'column': cols.append}) if cols: columns.append(cols[0]) ...
'Return the connectable associated with this Index.'
@property def bind(self):
return self.table.bind
'Issue a ``CREATE`` statement for this :class:`.Index`, using the given :class:`.Connectable` for connectivity. .. seealso:: :meth:`.MetaData.create_all`.'
def create(self, bind=None):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaGenerator, self) return self
'Issue a ``DROP`` statement for this :class:`.Index`, using the given :class:`.Connectable` for connectivity. .. seealso:: :meth:`.MetaData.drop_all`.'
def drop(self, bind=None):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaDropper, self)
'Create a new MetaData object. :param bind: An Engine or Connection to bind to. May also be a string or URL instance, these are passed to create_engine() and this MetaData will be bound to the resulting engine. :param reflect: Optional, automatically load all tables from the bound database. Defaults to False. ``bind``...
def __init__(self, bind=None, reflect=False, schema=None, quote_schema=None, naming_convention=DEFAULT_NAMING_CONVENTION):
self.tables = util.immutabledict() self.schema = quoted_name(schema, quote_schema) self.naming_convention = naming_convention self._schemas = set() self._sequences = {} self._fk_memos = collections.defaultdict(list) self.bind = bind if reflect: util.warn_deprecated('reflect=True ...
'True if this MetaData is bound to an Engine or Connection.'
def is_bound(self):
return (self._bind is not None)
'An :class:`.Engine` or :class:`.Connection` to which this :class:`.MetaData` is bound. Typically, a :class:`.Engine` is assigned to this attribute so that "implicit execution" may be used, or alternatively as a means of providing engine binding information to an ORM :class:`.Session` object:: engine = create_engine("s...
def bind(self):
return self._bind
'Bind this MetaData to an Engine, Connection, string or URL.'
@util.dependencies('sqlalchemy.engine.url') def _bind_to(self, url, bind):
if isinstance(bind, (util.string_types + (url.URL,))): self._bind = sqlalchemy.create_engine(bind) else: self._bind = bind
'Clear all Table objects from this MetaData.'
def clear(self):
dict.clear(self.tables) self._schemas.clear() self._fk_memos.clear()
'Remove the given Table object from this MetaData.'
def remove(self, table):
self._remove_table(table.name, table.schema)
'Returns a list of :class:`.Table` objects sorted in order of foreign key dependency. The sorting will place :class:`.Table` objects that have dependencies first, before the dependencies themselves, representing the order in which they can be created. To get the order in which the tables would be dropped, use the ``r...
@property def sorted_tables(self):
return ddl.sort_tables(self.tables.values())
'Load all available table definitions from the database. Automatically creates ``Table`` entries in this ``MetaData`` for any table available in the database but not yet present in the ``MetaData``. May be called multiple times to pick up tables recently added to the database, however no special action is taken if a t...
def reflect(self, bind=None, schema=None, views=False, only=None, extend_existing=False, autoload_replace=True, **dialect_kwargs):
if (bind is None): bind = _bind_or_error(self) with bind.connect() as conn: reflect_opts = {'autoload': True, 'autoload_with': conn, 'extend_existing': extend_existing, 'autoload_replace': autoload_replace} reflect_opts.update(dialect_kwargs) if (schema is None): sche...
'Append a DDL event listener to this ``MetaData``. .. deprecated:: 0.7 See :class:`.DDLEvents`.'
def append_ddl_listener(self, event_name, listener):
def adapt_listener(target, connection, **kw): tables = kw['tables'] listener(event, target, connection, tables=tables) event.listen(self, ('' + event_name.replace('-', '_')), adapt_listener)
'Create all tables stored in this metadata. Conditional by default, will not attempt to recreate tables already present in the target database. :param bind: A :class:`.Connectable` used to access the database; if None, uses the existing bind on this ``MetaData``, if any. :param tables: Optional list of ``Table`` object...
def create_all(self, bind=None, tables=None, checkfirst=True):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst, tables=tables)
'Drop all tables stored in this metadata. Conditional by default, will not attempt to drop tables not present in the target database. :param bind: A :class:`.Connectable` used to access the database; if None, uses the existing bind on this ``MetaData``, if any. :param tables: Optional list of ``Table`` objects, which i...
def drop_all(self, bind=None, tables=None, checkfirst=True):
if (bind is None): bind = _bind_or_error(self) bind._run_visitor(ddl.SchemaDropper, self, checkfirst=checkfirst, tables=tables)
'Construct a ThreadLocalMetaData.'
def __init__(self):
self.context = util.threading.local() self.__engines = {} super(ThreadLocalMetaData, self).__init__()
'The bound Engine or Connection for this thread. This property may be assigned an Engine or Connection, or assigned a string or URL to automatically create a basic Engine for this bind with ``create_engine()``.'
def bind(self):
return getattr(self.context, '_engine', None)
'Bind to a Connectable in the caller\'s thread.'
@util.dependencies('sqlalchemy.engine.url') def _bind_to(self, url, bind):
if isinstance(bind, (util.string_types + (url.URL,))): try: self.context._engine = self.__engines[bind] except KeyError: e = sqlalchemy.create_engine(bind) self.__engines[bind] = e self.context._engine = e else: if (bind not in self.__engin...
'True if there is a bind for this thread.'
def is_bound(self):
return (hasattr(self.context, '_engine') and (self.context._engine is not None))
'Dispose all bound engines, in all thread contexts.'
def dispose(self):
for e in self.__engines.values(): if hasattr(e, 'dispose'): e.dispose()
'Construct a new ``Compiled`` object. :param dialect: ``Dialect`` to compile against. :param statement: ``ClauseElement`` to be compiled. :param bind: Optional Engine or Connection to compile this statement against. :param compile_kwargs: additional kwargs that will be passed to the initial call to :meth:`.Compiled.pro...
def __init__(self, dialect, statement, bind=None, compile_kwargs=util.immutabledict()):
self.dialect = dialect self.bind = bind if (statement is not None): self.statement = statement self.can_execute = statement.supports_execution self.string = self.process(self.statement, **compile_kwargs)
'Produce the internal string representation of this element.'
@util.deprecated('0.7', ':class:`.Compiled` objects now compile within the constructor.') def compile(self):
pass
'Return a Compiled that is capable of processing SQL expressions. If this compiler is one, it would likely just return \'self\'.'
@property def sql_compiler(self):
raise NotImplementedError()
'Return the string text of the generated SQL or DDL.'
def __str__(self):
return (self.string or '')
'Return the bind params for this compiled object. :param params: a dict of string/object pairs whose values will override bind values compiled in to the statement.'
def construct_params(self, params=None):
raise NotImplementedError()
'Return the bind params for this compiled object.'
@property def params(self):
return self.construct_params()
'Execute this compiled object.'
def execute(self, *multiparams, **params):
e = self.bind if (e is None): raise exc.UnboundExecutionError('This Compiled object is not bound to any Engine or Connection.') return e._execute_compiled(self, multiparams, params)
'Execute this compiled object and return the result\'s scalar value.'
def scalar(self, *multiparams, **params):
return self.execute(*multiparams, **params).scalar()
'Construct a new ``DefaultCompiler`` object. dialect Dialect to be used statement ClauseElement to be compiled column_keys a list of column names to be compiled into an INSERT or UPDATE statement.'
def __init__(self, dialect, statement, column_keys=None, inline=False, **kwargs):
self.column_keys = column_keys self.inline = (inline or getattr(statement, 'inline', False)) self.binds = {} self.bind_names = util.column_dict() self.stack = [] self.result_map = {} self.positional = dialect.positional if self.positional: self.positiontup = [] self.bindtempl...
'Initialize collections related to CTEs only if a CTE is located, to save on the overhead of these collections otherwise.'
@util.memoized_instancemethod def _init_cte_state(self):
self.ctes = util.OrderedDict() self.ctes_by_name = {} self.ctes_recursive = False if self.positional: self.cte_positional = []
'return a dictionary of bind parameter keys and values'
def construct_params(self, params=None, _group_number=None, _check=True):
if params: pd = {} for (bindparam, name) in self.bind_names.items(): if (bindparam.key in params): pd[name] = params[bindparam.key] elif (name in params): pd[name] = params[name] elif (_check and bindparam.required): ...
'Return the bind param dictionary embedded into this compiled object, for those values that are present.'
@property def params(self):
return self.construct_params(_check=False)
'Called when a SELECT statement has no froms, and no FROM clause is to be appended. Gives Oracle a chance to tack on a ``FROM DUAL`` to the string output.'
def default_from(self):
return ''
'provide escaping for the literal_column() construct.'
def escape_literal_column(self, text):
return text.replace('%', '%%')
'Render the value of a bind parameter as a quoted literal. This is used for statement sections that do not accept bind parameters on the target driver/database. This should be implemented by subclasses using the quoting services of the DBAPI.'
def render_literal_value(self, value, type_):
processor = type_._cached_literal_processor(self.dialect) if processor: return processor(value) else: raise NotImplementedError(("Don't know how to literal-quote value %r" % value))
'produce labeled columns present in a select().'
def _label_select_column(self, select, column, populate_result_map, asfrom, column_clause_args, name=None, within_columns_clause=True):
if (column.type._has_column_expression and populate_result_map): col_expr = column.type.column_expression(column) add_to_result_map = (lambda keyname, name, objects, type_: self._add_to_result_map(keyname, name, (objects + (column,)), type_)) else: col_expr = column if populate_r...
'Rewrite any "a JOIN (b JOIN c)" expression as "a JOIN (select * from b JOIN c) AS anon", to support databases that can\'t parse a parenthesized join correctly (i.e. sqlite the main one).'
def _transform_select_for_nested_joins(self, select):
cloned = {} column_translate = [{}] def visit(element, **kw): if (element in column_translate[(-1)]): return column_translate[(-1)][element] elif (element in cloned): return cloned[element] newelem = cloned[element] = element._clone() if (newelem.is_se...
'Called when building a ``SELECT`` statement, position is just before column list.'
def get_select_precolumns(self, select):
return ((select._distinct and 'DISTINCT ') or '')
'Provide a hook for MySQL to add LIMIT to the UPDATE'
def update_limit_clause(self, update_stmt):
return None
'Provide a hook to override the initial table clause in an UPDATE statement. MySQL overrides this.'
def update_tables_clause(self, update_stmt, from_table, extra_froms, **kw):
return from_table._compiler_dispatch(self, asfrom=True, iscrud=True, **kw)
'Provide a hook to override the generation of an UPDATE..FROM clause. MySQL and MSSQL override this.'
def update_from_clause(self, update_stmt, from_table, extra_froms, from_hints, **kw):
return ('FROM ' + ', '.join((t._compiler_dispatch(self, asfrom=True, fromhints=from_hints, **kw) for t in extra_froms)))
'create a set of tuples representing column/string pairs for use in an INSERT or UPDATE statement. Also generates the Compiled object\'s postfetch, prefetch, and returning column collections, used for default handling and ultimately populating the ResultProxy\'s prefetch_cols() and postfetch_cols() collections.'
def _get_colparams(self, stmt, **kw):
self.postfetch = [] self.prefetch = [] self.returning = [] if ((self.column_keys is None) and (stmt.parameters is None)): return [(c, self._create_crud_bind_param(c, None, required=True)) for c in stmt.table.columns] if stmt._has_multi_parameters: stmt_parameters = stmt.parameters[0]...
'Format the remote table clause of a CREATE CONSTRAINT clause.'
def define_constraint_remote_table(self, constraint, table, preparer):
return preparer.format_table(table)
'Construct a new ``IdentifierPreparer`` object. initial_quote Character that begins a delimited identifier. final_quote Character that ends a delimited identifier. Defaults to `initial_quote`. omit_schema Prevent prepending schema name. Useful for databases that do not support schemae.'
def __init__(self, dialect, initial_quote='"', final_quote=None, escape_quote='"', omit_schema=False):
self.dialect = dialect self.initial_quote = initial_quote self.final_quote = (final_quote or self.initial_quote) self.escape_quote = escape_quote self.escape_to_quote = (self.escape_quote * 2) self.omit_schema = omit_schema self._strings = {}
'Escape an identifier. Subclasses should override this to provide database-dependent escaping behavior.'
def _escape_identifier(self, value):
return value.replace(self.escape_quote, self.escape_to_quote)
'Canonicalize an escaped identifier. Subclasses should override this to provide database-dependent unescaping behavior that reverses _escape_identifier.'
def _unescape_identifier(self, value):
return value.replace(self.escape_to_quote, self.escape_quote)
'Quote an identifier. Subclasses should override this to provide database-dependent quoting behavior.'
def quote_identifier(self, value):
return ((self.initial_quote + self._escape_identifier(value)) + self.final_quote)
'Return True if the given identifier requires quoting.'
def _requires_quotes(self, value):
lc_value = value.lower() return ((lc_value in self.reserved_words) or (value[0] in self.illegal_initial_characters) or (not self.legal_characters.match(util.text_type(value))) or (lc_value != value))
'Conditionally quote a schema. Subclasses can override this to provide database-dependent quoting behavior for schema names. the \'force\' flag should be considered deprecated.'
def quote_schema(self, schema, force=None):
return self.quote(schema, force)
'Conditionally quote an identifier. the \'force\' flag should be considered deprecated.'
def quote(self, ident, force=None):
force = getattr(ident, 'quote', None) if (force is None): if (ident in self._strings): return self._strings[ident] else: if self._requires_quotes(ident): self._strings[ident] = self.quote_identifier(ident) else: self._strings[id...
'Prepare a quoted table and schema name.'
def format_table(self, table, use_schema=True, name=None):
if (name is None): name = table.name result = self.quote(name) if ((not self.omit_schema) and use_schema and getattr(table, 'schema', None)): result = ((self.quote_schema(table.schema) + '.') + result) return result
'Prepare a quoted schema name.'
def format_schema(self, name, quote=None):
return self.quote(name, quote)
'Prepare a quoted column name.'
def format_column(self, column, use_table=False, name=None, table_name=None):
if (name is None): name = column.name if (not getattr(column, 'is_literal', False)): if use_table: return ((self.format_table(column.table, use_schema=False, name=table_name) + '.') + self.quote(name)) else: return self.quote(name) elif use_table: retu...
'Format table name and schema as a tuple.'
def format_table_seq(self, table, use_schema=True):
if ((not self.omit_schema) and use_schema and getattr(table, 'schema', None)): return (self.quote_schema(table.schema), self.format_table(table, use_schema=False)) else: return (self.format_table(table, use_schema=False),)
'Unpack \'schema.table.column\'-like strings into components.'
def unformat_identifiers(self, identifiers):
r = self._r_identifiers return [self._unescape_identifier(i) for i in [(a or b) for (a, b) in r.findall(identifiers)]]
'Create a \'join\' of this :class:`._Dispatch` and another. This new dispatcher will dispatch events to both :class:`._Dispatch` objects.'
def _join(self, other):
if ('_joined_dispatch_cls' not in self.__class__.__dict__): cls = type(('Joined%s' % self.__class__.__name__), (_JoinedDispatcher, self.__class__), {}) for ls in _event_descriptors(self): setattr(cls, ls.name, _JoinedDispatchDescriptor(ls.name)) self.__class__._joined_dispatch_cl...