157 lines
5.0 KiB
Python
157 lines
5.0 KiB
Python
import re
|
|
|
|
from .impl import DefaultImpl
|
|
from .. import util
|
|
|
|
|
|
class SQLiteImpl(DefaultImpl):
|
|
__dialect__ = "sqlite"
|
|
|
|
transactional_ddl = False
|
|
"""SQLite supports transactional DDL, but pysqlite does not:
|
|
see: http://bugs.python.org/issue10740
|
|
"""
|
|
|
|
def requires_recreate_in_batch(self, batch_op):
|
|
"""Return True if the given :class:`.BatchOperationsImpl`
|
|
would need the table to be recreated and copied in order to
|
|
proceed.
|
|
|
|
Normally, only returns True on SQLite when operations other
|
|
than add_column are present.
|
|
|
|
"""
|
|
for op in batch_op.batch:
|
|
if op[0] not in ("add_column", "create_index", "drop_index"):
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
def add_constraint(self, const):
|
|
# attempt to distinguish between an
|
|
# auto-gen constraint and an explicit one
|
|
if const._create_rule is None:
|
|
raise NotImplementedError(
|
|
"No support for ALTER of constraints in SQLite dialect"
|
|
)
|
|
elif const._create_rule(self):
|
|
util.warn(
|
|
"Skipping unsupported ALTER for "
|
|
"creation of implicit constraint"
|
|
)
|
|
|
|
def drop_constraint(self, const):
|
|
if const._create_rule is None:
|
|
raise NotImplementedError(
|
|
"No support for ALTER of constraints in SQLite dialect"
|
|
)
|
|
|
|
def compare_server_default(
|
|
self,
|
|
inspector_column,
|
|
metadata_column,
|
|
rendered_metadata_default,
|
|
rendered_inspector_default,
|
|
):
|
|
|
|
if rendered_metadata_default is not None:
|
|
rendered_metadata_default = re.sub(
|
|
r"^\((.+)\)$", r"\1", rendered_metadata_default
|
|
)
|
|
|
|
rendered_metadata_default = re.sub(
|
|
r"^\"?'(.+)'\"?$", r"\1", rendered_metadata_default
|
|
)
|
|
|
|
if rendered_inspector_default is not None:
|
|
rendered_inspector_default = re.sub(
|
|
r"^\"?'(.+)'\"?$", r"\1", rendered_inspector_default
|
|
)
|
|
|
|
return rendered_inspector_default != rendered_metadata_default
|
|
|
|
def correct_for_autogen_constraints(
|
|
self,
|
|
conn_unique_constraints,
|
|
conn_indexes,
|
|
metadata_unique_constraints,
|
|
metadata_indexes,
|
|
):
|
|
|
|
if util.sqla_100:
|
|
return
|
|
|
|
# adjustments to accommodate for SQLite unnamed unique constraints
|
|
# not being reported from the backend; this was updated in
|
|
# SQLA 1.0.
|
|
|
|
def uq_sig(uq):
|
|
return tuple(sorted(uq.columns.keys()))
|
|
|
|
conn_unique_sigs = set(uq_sig(uq) for uq in conn_unique_constraints)
|
|
|
|
for idx in list(metadata_unique_constraints):
|
|
# SQLite backend can't report on unnamed UNIQUE constraints,
|
|
# so remove these, unless we see an exact signature match
|
|
if idx.name is None and uq_sig(idx) not in conn_unique_sigs:
|
|
metadata_unique_constraints.remove(idx)
|
|
|
|
def _guess_if_default_is_unparenthesized_sql_expr(self, expr):
|
|
"""Determine if a server default is a SQL expression or a constant.
|
|
|
|
There are too many assertions that expect server defaults to round-trip
|
|
identically without parenthesis added so we will add parens only in
|
|
very specific cases.
|
|
|
|
"""
|
|
if not expr:
|
|
return False
|
|
elif re.match(r"^[0-9\.]$", expr):
|
|
return False
|
|
elif re.match(r"^'.+'$", expr):
|
|
return False
|
|
elif re.match(r"^\(.+\)$", expr):
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
def autogen_column_reflect(self, inspector, table, column_info):
|
|
# SQLite expression defaults require parenthesis when sent
|
|
# as DDL
|
|
if self._guess_if_default_is_unparenthesized_sql_expr(
|
|
column_info.get("default", None)
|
|
):
|
|
column_info["default"] = "(%s)" % (column_info["default"],)
|
|
|
|
def render_ddl_sql_expr(self, expr, is_server_default=False, **kw):
|
|
# SQLite expression defaults require parenthesis when sent
|
|
# as DDL
|
|
str_expr = super(SQLiteImpl, self).render_ddl_sql_expr(
|
|
expr, is_server_default=is_server_default, **kw
|
|
)
|
|
|
|
if (
|
|
is_server_default
|
|
and self._guess_if_default_is_unparenthesized_sql_expr(str_expr)
|
|
):
|
|
str_expr = "(%s)" % (str_expr,)
|
|
return str_expr
|
|
|
|
|
|
# @compiles(AddColumn, 'sqlite')
|
|
# def visit_add_column(element, compiler, **kw):
|
|
# return "%s %s" % (
|
|
# alter_table(compiler, element.table_name, element.schema),
|
|
# add_column(compiler, element.column, **kw)
|
|
# )
|
|
|
|
|
|
# def add_column(compiler, column, **kw):
|
|
# text = "ADD COLUMN %s" % compiler.get_column_specification(column, **kw)
|
|
# need to modify SQLAlchemy so that the CHECK associated with a Boolean
|
|
# or Enum gets placed as part of the column constraints, not the Table
|
|
# see ticket 98
|
|
# for const in column.constraints:
|
|
# text += compiler.process(AddConstraint(const))
|
|
# return text
|