def add_column(operations, operation):
table_name = operation.table_name
column = operation.column
schema = operation.schema
t = operations.schema_obj.table(table_name, column, schema=schema)
operations.impl.add_column(
table_name,
column,
schema=schema
)
for constraint in t.constraints:
if not isinstance(constraint, sa_schema.PrimaryKeyConstraint):
operations.impl.add_constraint(constraint)
for index in t.indexes:
operations.impl.create_index(index)
python类PrimaryKeyConstraint()的实例源码
def drop_constraint(self, const):
if not const.name:
raise ValueError("Constraint must have a name")
try:
const = self.named_constraints.pop(const.name)
except KeyError:
if _is_type_bound(const):
# type-bound constraints are only included in the new
# table via their type object in any case, so ignore the
# drop_constraint() that comes here via the
# Operations.implementation_for(alter_column)
return
raise ValueError("No such constraint: '%s'" % const.name)
else:
if isinstance(const, PrimaryKeyConstraint):
for col in const.columns:
self.columns[col.name].primary_key = False
def _mysql_drop_constraint(element, compiler, **kw):
"""Redefine SQLAlchemy's drop constraint to
raise errors for invalid constraint type."""
constraint = element.element
if isinstance(constraint, (schema.ForeignKeyConstraint,
schema.PrimaryKeyConstraint,
schema.UniqueConstraint)
):
return compiler.visit_drop_constraint(element, **kw)
elif isinstance(constraint, schema.CheckConstraint):
raise NotImplementedError(
"MySQL does not support CHECK constraints.")
else:
raise NotImplementedError(
"No generic 'DROP CONSTRAINT' in MySQL - "
"please specify constraint type")
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 add_column(operations, operation):
table_name = operation.table_name
column = operation.column
schema = operation.schema
t = operations.schema_obj.table(table_name, column, schema=schema)
operations.impl.add_column(
table_name,
column,
schema=schema
)
for constraint in t.constraints:
if not isinstance(constraint, sa_schema.PrimaryKeyConstraint):
operations.impl.add_constraint(constraint)
for index in t.indexes:
operations.impl.create_index(index)
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 _primary_key_constraint(self, name, table_name, cols, schema=None):
m = sa_schema.MetaData()
columns = [sa_schema.Column(n, NULLTYPE) for n in cols]
t1 = sa_schema.Table(table_name, m,
*columns,
schema=schema)
p = sa_schema.PrimaryKeyConstraint(*columns, name=name)
t1.append_constraint(p)
return p
def create_primary_key(self, name, table_name, cols, schema=None):
"""Issue a "create primary key" instruction using the current
migration context.
e.g.::
from alembic import op
op.create_primary_key(
"pk_my_table", "my_table",
["id", "version"]
)
This internally generates a :class:`~sqlalchemy.schema.Table` object
containing the necessary columns, then generates a new
:class:`~sqlalchemy.schema.PrimaryKeyConstraint`
object which it then associates with the :class:`~sqlalchemy.schema.Table`.
Any event listeners associated with this action will be fired
off normally. The :class:`~sqlalchemy.schema.AddConstraint`
construct is ultimately used to generate the ALTER statement.
.. versionadded:: 0.5.0
:param name: Name of the primary key constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
`NamingConventions <http://www.sqlalchemy.org/trac/wiki/UsageRecipes/NamingConventions>`_,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the target table.
:param cols: a list of string column names to be applied to the
primary key constraint.
:param schema: Optional schema name of the table.
"""
self.impl.add_constraint(
self._primary_key_constraint(name, table_name, cols,
schema)
)
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 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 _primary_key_constraint(self, name, table_name, cols, schema=None):
m = sa_schema.MetaData()
columns = [sa_schema.Column(n, NULLTYPE) for n in cols]
t1 = sa_schema.Table(table_name, m,
*columns,
schema=schema)
p = sa_schema.PrimaryKeyConstraint(*columns, name=name)
t1.append_constraint(p)
return p
def create_primary_key(self, name, table_name, cols, schema=None):
"""Issue a "create primary key" instruction using the current
migration context.
e.g.::
from alembic import op
op.create_primary_key(
"pk_my_table", "my_table",
["id", "version"]
)
This internally generates a :class:`~sqlalchemy.schema.Table` object
containing the necessary columns, then generates a new
:class:`~sqlalchemy.schema.PrimaryKeyConstraint`
object which it then associates with the :class:`~sqlalchemy.schema.Table`.
Any event listeners associated with this action will be fired
off normally. The :class:`~sqlalchemy.schema.AddConstraint`
construct is ultimately used to generate the ALTER statement.
.. versionadded:: 0.5.0
:param name: Name of the primary key constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
`NamingConventions <http://www.sqlalchemy.org/trac/wiki/UsageRecipes/NamingConventions>`_,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the target table.
:param cols: a list of string column names to be applied to the
primary key constraint.
:param schema: Optional schema name of the table.
"""
self.impl.add_constraint(
self._primary_key_constraint(name, table_name, cols,
schema)
)
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 visit_column(self, column):
"""Firebird supports 'DROP col' instead of 'DROP COLUMN col' syntax
Drop primary key and unique constraints if dropped column is referencing it."""
if column.primary_key:
if column.table.primary_key.columns.contains_column(column):
column.table.primary_key.drop()
# TODO: recreate primary key if it references more than this column
for index in column.table.indexes:
# "column in index.columns" causes problems as all
# column objects compare equal and return a SQL expression
if column.name in [col.name for col in index.columns]:
index.drop()
# TODO: recreate index if it references more than this column
for cons in column.table.constraints:
if isinstance(cons,PrimaryKeyConstraint):
# will be deleted only when the column its on
# is deleted!
continue
should_drop = column.name in cons.columns
if should_drop:
self.start_alter_table(column)
self.append("DROP CONSTRAINT ")
self.append(self.preparer.format_constraint(cons))
self.execute()
# TODO: recreate unique constraint if it refenrences more than this column
self.start_alter_table(column)
self.append('DROP %s' % self.preparer.format_column(column))
self.execute()
def __init__(self, *cols, **kwargs):
colnames, table = self._normalize_columns(cols)
table = kwargs.pop('table', table)
super(PrimaryKeyConstraint, self).__init__(*colnames, **kwargs)
if table is not None:
self._set_parent(table)
def _primary_key_constraint(self, name, table_name, cols, schema=None):
m = self._metadata()
columns = [sa_schema.Column(n, NULLTYPE) for n in cols]
t1 = sa_schema.Table(table_name, m,
*columns,
schema=schema)
p = sa_schema.PrimaryKeyConstraint(*columns, name=name)
t1.append_constraint(p)
return p
def drop_constraint(self, name, table_name, type_=None, schema=None):
"""Drop a constraint of the given name, typically via DROP CONSTRAINT.
:param name: name of the constraint.
:param table_name: table name.
:param ``type_``: optional, required on MySQL. can be
'foreignkey', 'primary', 'unique', or 'check'.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
"""
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)))
const = const(name=name)
t.append_constraint(const)
self.impl.drop_constraint(const)
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 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 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
