def drop_all_tables(engine, inspector, schema=None, include_names=None):
from sqlalchemy import Column, Table, Integer, MetaData, \
ForeignKeyConstraint
from sqlalchemy.schema import DropTable, DropConstraint
if include_names is not None:
include_names = set(include_names)
with engine.connect() as conn:
for tname, fkcs in reversed(
inspector.get_sorted_table_and_fkc_names(schema=schema)):
if tname:
if include_names is not None and tname not in include_names:
continue
conn.execute(DropTable(
Table(tname, MetaData(), schema=schema)
))
elif fkcs:
if not engine.dialect.supports_alter:
continue
for tname, fkc in fkcs:
if include_names is not None and \
tname not in include_names:
continue
tb = Table(
tname, MetaData(),
Column('x', Integer),
Column('y', Integer),
schema=schema
)
conn.execute(DropConstraint(
ForeignKeyConstraint(
[tb.c.x], [tb.c.y], name=fkc)
))
python类DropConstraint()的实例源码
def drop_all_tables(engine, inspector, schema=None, include_names=None):
from sqlalchemy import Column, Table, Integer, MetaData, \
ForeignKeyConstraint
from sqlalchemy.schema import DropTable, DropConstraint
if include_names is not None:
include_names = set(include_names)
with engine.connect() as conn:
for tname, fkcs in reversed(
inspector.get_sorted_table_and_fkc_names(schema=schema)):
if tname:
if include_names is not None and tname not in include_names:
continue
conn.execute(DropTable(
Table(tname, MetaData(), schema=schema)
))
elif fkcs:
if not engine.dialect.supports_alter:
continue
for tname, fkc in fkcs:
if include_names is not None and \
tname not in include_names:
continue
tb = Table(
tname, MetaData(),
Column('x', Integer),
Column('y', Integer),
schema=schema
)
conn.execute(DropConstraint(
ForeignKeyConstraint(
[tb.c.x], [tb.c.y], name=fkc)
))
def drop_all_tables(engine, inspector, schema=None, include_names=None):
from sqlalchemy import Column, Table, Integer, MetaData, \
ForeignKeyConstraint
from sqlalchemy.schema import DropTable, DropConstraint
if include_names is not None:
include_names = set(include_names)
with engine.connect() as conn:
for tname, fkcs in reversed(
inspector.get_sorted_table_and_fkc_names(schema=schema)):
if tname:
if include_names is not None and tname not in include_names:
continue
conn.execute(DropTable(
Table(tname, MetaData())
))
elif fkcs:
if not engine.dialect.supports_alter:
continue
for tname, fkc in fkcs:
if include_names is not None and \
tname not in include_names:
continue
tb = Table(
tname, MetaData(),
Column('x', Integer),
Column('y', Integer),
schema=schema
)
conn.execute(DropConstraint(
ForeignKeyConstraint(
[tb.c.x], [tb.c.y], name=fkc)
))
def _visit_constraint(self, constraint):
constraint.name = self.get_constraint_name(constraint)
self.append(self.process(DropConstraint(constraint, cascade=constraint.cascade)))
self.execute()
def drop_all_tables(engine, inspector, schema=None, include_names=None):
from sqlalchemy import Column, Table, Integer, MetaData, \
ForeignKeyConstraint
from sqlalchemy.schema import DropTable, DropConstraint
if include_names is not None:
include_names = set(include_names)
with engine.connect() as conn:
for tname, fkcs in reversed(
inspector.get_sorted_table_and_fkc_names(schema=schema)):
if tname:
if include_names is not None and tname not in include_names:
continue
conn.execute(DropTable(
Table(tname, MetaData(), schema=schema)
))
elif fkcs:
if not engine.dialect.supports_alter:
continue
for tname, fkc in fkcs:
if include_names is not None and \
tname not in include_names:
continue
tb = Table(
tname, MetaData(),
Column('x', Integer),
Column('y', Integer),
schema=schema
)
conn.execute(DropConstraint(
ForeignKeyConstraint(
[tb.c.x], [tb.c.y], name=fkc)
))
def drop_all_tables(engine, inspector, schema=None, include_names=None):
from sqlalchemy import Column, Table, Integer, MetaData, \
ForeignKeyConstraint
from sqlalchemy.schema import DropTable, DropConstraint
if include_names is not None:
include_names = set(include_names)
with engine.connect() as conn:
for tname, fkcs in reversed(
inspector.get_sorted_table_and_fkc_names(schema=schema)):
if tname:
if include_names is not None and tname not in include_names:
continue
conn.execute(DropTable(
Table(tname, MetaData(), schema=schema)
))
elif fkcs:
if not engine.dialect.supports_alter:
continue
for tname, fkc in fkcs:
if include_names is not None and \
tname not in include_names:
continue
tb = Table(
tname, MetaData(),
Column('x', Integer),
Column('y', Integer),
schema=schema
)
conn.execute(DropConstraint(
ForeignKeyConstraint(
[tb.c.x], [tb.c.y], name=fkc)
))
def drop_constraint(self, const):
self._exec(schema.DropConstraint(const))
def drop_everything(echo=True):
""" Pre-gather all named constraints and table names, and drop everything. This is better than using metadata.reflect();
metadata.drop_all() as it handles cyclical constraints between tables.
Ref. http://www.sqlalchemy.org/trac/wiki/UsageRecipes/DropEverything
"""
engine = session.get_engine(echo=echo)
conn = engine.connect()
# the transaction only applies if the DB supports
# transactional DDL, i.e. Postgresql, MS SQL Server
trans = conn.begin()
inspector = reflection.Inspector.from_engine(engine)
# gather all data first before dropping anything.
# some DBs lock after things have been dropped in
# a transaction.
metadata = MetaData()
tbs = []
all_fks = []
for table_name in inspector.get_table_names():
fks = []
for fk in inspector.get_foreign_keys(table_name):
if not fk['name']:
continue
fks.append(ForeignKeyConstraint((), (), name=fk['name']))
t = Table(table_name, metadata, *fks)
tbs.append(t)
all_fks.extend(fks)
for fkc in all_fks:
try:
print str(DropConstraint(fkc)) + ';'
conn.execute(DropConstraint(fkc))
except:
print format_exc()
for table in tbs:
try:
print str(DropTable(table)).strip() + ';'
conn.execute(DropTable(table))
except:
print format_exc()
trans.commit()
