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from sqlalchemy import schema as sa_schema
from sqlalchemy.types import NULLTYPE, Integer
from ..util.compat import string_types
from .. import util
class SchemaObjects(object):
def __init__(self, migration_context=None):
self.migration_context = migration_context
def primary_key_constraint(self, name, table_name, cols, schema=None):
m = self.metadata()
columns = [sa_schema.Column(n, NULLTYPE) for n in cols]
t = sa_schema.Table(
table_name, m,
*columns,
schema=schema)
p = sa_schema.PrimaryKeyConstraint(
*[t.c[n] for n in cols], name=name)
t.append_constraint(p)
return p
def foreign_key_constraint(
self, name, source, referent,
local_cols, remote_cols,
onupdate=None, ondelete=None,
deferrable=None, source_schema=None,
referent_schema=None, initially=None,
match=None, **dialect_kw):
m = self.metadata()
if source == referent:
t1_cols = local_cols + remote_cols
else:
t1_cols = local_cols
sa_schema.Table(
referent, m,
*[sa_schema.Column(n, NULLTYPE) for n in remote_cols],
schema=referent_schema)
t1 = sa_schema.Table(
source, m,
*[sa_schema.Column(n, NULLTYPE) for n in t1_cols],
schema=source_schema)
tname = "%s.%s" % (referent_schema, referent) if referent_schema \
else referent
if util.sqla_08:
# "match" kw unsupported in 0.7
dialect_kw['match'] = match
f = sa_schema.ForeignKeyConstraint(local_cols,
["%s.%s" % (tname, n)
for n in remote_cols],
name=name,
onupdate=onupdate,
ondelete=ondelete,
deferrable=deferrable,
initially=initially,
**dialect_kw
)
t1.append_constraint(f)
return f
def unique_constraint(self, name, source, local_cols, schema=None, **kw):
t = sa_schema.Table(
source, self.metadata(),
*[sa_schema.Column(n, NULLTYPE) for n in local_cols],
schema=schema)
kw['name'] = name
uq = sa_schema.UniqueConstraint(*[t.c[n] for n in local_cols], **kw)
# TODO: need event tests to ensure the event
# is fired off here
t.append_constraint(uq)
return uq
def check_constraint(self, name, source, condition, schema=None, **kw):
t = sa_schema.Table(source, self.metadata(),
sa_schema.Column('x', Integer), schema=schema)
ck = sa_schema.CheckConstraint(condition, name=name, **kw)
t.append_constraint(ck)
return ck
def generic_constraint(self, name, table_name, type_, schema=None, **kw):
t = self.table(table_name, schema=schema)
types = {
'foreignkey': lambda name: sa_schema.ForeignKeyConstraint(
[], [], name=name),
'primary': sa_schema.PrimaryKeyConstraint,
'unique': sa_schema.UniqueConstraint,
'check': lambda name: sa_schema.CheckConstraint("", name=name),
None: sa_schema.Constraint
}
try:
const = types[type_]
except KeyError:
raise TypeError("'type' can be one of %s" %
", ".join(sorted(repr(x) for x in types)))
else:
const = const(name=name)
t.append_constraint(const)
return const
def metadata(self):
kw = {}
if self.migration_context is not None and \
'target_metadata' in self.migration_context.opts:
mt = self.migration_context.opts['target_metadata']
if hasattr(mt, 'naming_convention'):
kw['naming_convention'] = mt.naming_convention
return sa_schema.MetaData(**kw)
def table(self, name, *columns, **kw):
m = self.metadata()
t = sa_schema.Table(name, m, *columns, **kw)
for f in t.foreign_keys:
self._ensure_table_for_fk(m, f)
return t
def column(self, name, type_, **kw):
return sa_schema.Column(name, type_, **kw)
def index(self, name, tablename, columns, schema=None, **kw):
t = sa_schema.Table(
tablename or 'no_table', self.metadata(),
schema=schema
)
idx = sa_schema.Index(
name,
*[util.sqla_compat._textual_index_column(t, n) for n in columns],
**kw)
return idx
def _parse_table_key(self, table_key):
if '.' in table_key:
tokens = table_key.split('.')
sname = ".".join(tokens[0:-1])
tname = tokens[-1]
else:
tname = table_key
sname = None
return (sname, tname)
def _ensure_table_for_fk(self, metadata, fk):
"""create a placeholder Table object for the referent of a
ForeignKey.
"""
if isinstance(fk._colspec, string_types):
table_key, cname = fk._colspec.rsplit('.', 1)
sname, tname = self._parse_table_key(table_key)
if table_key not in metadata.tables:
rel_t = sa_schema.Table(tname, metadata, schema=sname)
else:
rel_t = metadata.tables[table_key]
if cname not in rel_t.c:
rel_t.append_column(sa_schema.Column(cname, NULLTYPE))
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