x/sqlalchemy-migrate
Code Issues Proposed changes

make migrate.schema.ansisql PEP8 clean and add some sphinx docstrings

Browse Source
This commit is contained in:
jan.dittberner 2009-01-25 12:51:49 +00:00
parent 6e22528e6f
commit 4806e2c9e1
1 changed files with 151 additions and 106 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

257
migrate/changeset/ansisql.py
View File

@ -1,47 +1,64 @@
"""
Module :mod:`migrate.changeset.ansisql`
---------------------------------------
Extensions to SQLAlchemy for altering existing tables.
Extensions to SQLAlchemy for altering existing tables.
At the moment, this isn't so much based off of ANSI as much as things that just
happen to work with multiple databases.
At the moment, this isn't so much based off of ANSI as much as
things that just happen to work with multiple databases.
"""
import sqlalchemy as sa
from sqlalchemy.engine.base import Connection, Dialect
from sqlalchemy.sql.compiler import SchemaGenerator
from migrate.changeset import constraint,exceptions
from sqlalchemy.schema import ForeignKeyConstraint
from migrate.changeset import constraint, exceptions
SchemaIterator = sa.engine.SchemaIterator
class RawAlterTableVisitor(object):
"""Common operations for 'alter table' statements"""
def _to_table(self,param):
if isinstance(param,(sa.Column,sa.Index,sa.schema.Constraint)):
"""Common operations for ``ALTER TABLE`` statements."""
def _to_table(self, param):
"""Returns the table object for the given param object."""
if isinstance(param, (sa.Column, sa.Index, sa.schema.Constraint)):
ret = param.table
else:
ret = param
return ret
def _to_table_name(self,param):
def _to_table_name(self, param):
"""Returns the table name for the given param object."""
ret = self._to_table(param)
if isinstance(ret,sa.Table):
if isinstance(ret, sa.Table):
ret = ret.fullname
return ret
def _do_quote_table_identifier(self, identifier):
"""Returns a quoted version of the given table identifier."""
return '"%s"'%identifier
def start_alter_table(self,param):
def start_alter_table(self, param):
"""Returns the start of an ``ALTER TABLE`` SQL-Statement.
Use the param object to determine the table name and use it
for building the SQL statement.
:param param: object to determine the table from. This may be
a :class:`sqlalchemy.Column`, an :class:`sqlalchemy.Index`,
a :class:`sqlachemy.schema.Constraint`, a
:class:`sqlalchemy.Table` or a table name string
"""
table = self._to_table(param)
table_name = self._to_table_name(table)
self.append('\nALTER TABLE %s ' % self._do_quote_table_identifier(table_name))
self.append('\nALTER TABLE %s ' % \
self._do_quote_table_identifier(table_name))
return table
def _pk_constraint(self,table,column,status):
"""Create a primary key constraint from a table, column
def _pk_constraint(self, table, column, status):
"""Create a primary key constraint from a table, column.
Status: true if the constraint is being added; false if being dropped
"""
if isinstance(column,basestring):
column = getattr(table.c,name)
if isinstance(column, basestring):
column = getattr(table.c, name)
ret = constraint.PrimaryKeyConstraint(*table.primary_key)
if status:
@ -55,17 +72,16 @@ class RawAlterTableVisitor(object):
del ret.c[index]
# Allow explicit PK name assignment
if isinstance(pk,basestring):
if isinstance(pk, basestring):
ret.name = pk
return ret
class AlterTableVisitor(SchemaIterator,RawAlterTableVisitor):
"""Common operations for 'alter table' statements"""
from sqlalchemy.schema import ForeignKeyConstraint
class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
class AlterTableVisitor(SchemaIterator, RawAlterTableVisitor):
"""Common operations for 'alter table' statements"""
class ANSIColumnGenerator(AlterTableVisitor, SchemaGenerator):
"""Extends ansisql generator for column creation (alter table add col)"""
#def __init__(self, *args, **kwargs):
# dialect = None
@ -78,7 +94,7 @@ class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
# super(ANSIColumnGenerator, self).__init__(dialect, *args,
# **kwargs)
def visit_column(self,column):
def visit_column(self, column):
"""Create a column (table already exists); #32"""
table = self.start_alter_table(column)
self.append(" ADD ")
@ -96,79 +112,87 @@ class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
# else:
self.execute()
def visit_table(self,table):
def visit_table(self, table):
pass
class ANSIColumnDropper(AlterTableVisitor):
"""Extends ansisql dropper for column dropping (alter table drop col)"""
def visit_column(self,column):
"""Extends ANSI SQL dropper for column dropping (``ALTER TABLE
DROP COLUMN``)."""
def visit_column(self, column):
"""Drop a column; #33"""
table = self.start_alter_table(column)
self.append(' DROP COLUMN %s'%self._do_quote_column_identifier(column.name))
self.append(' DROP COLUMN %s' % \
self._do_quote_column_identifier(column.name))
self.execute()
#if column.primary_key:
# cons = self._pk_constraint(table,column,False)
# cons.create()
class ANSISchemaChanger(AlterTableVisitor,SchemaGenerator):
"""Manages changes to existing schema elements.
Note that columns are schema elements; "alter table add column" is in
SchemaGenerator.
class ANSISchemaChanger(AlterTableVisitor, SchemaGenerator):
"""Manages changes to existing schema elements.
Note that columns are schema elements; ``ALTER TABLE ADD COLUMN``
is in SchemaGenerator.
All items may be renamed. Columns can also have many of their properties -
type, for example - changed.
Each function is passed a tuple, containing (object,name); where object
is a type of object you'd expect for that function (ie. table for
visit_table) and name is the object's new name. NONE means the name is
unchanged.
Each function is passed a tuple, containing (object,name); where
object is a type of object you'd expect for that function
(ie. table for visit_table) and name is the object's new
name. NONE means the name is unchanged.
"""
def _do_quote_column_identifier(self, identifier):
"""override this function to define how identifiers (table and column names) should be written in the sql.
for instance, in postgres, double quotes should surround the identifier
"""override this function to define how identifiers (table and
column names) should be written in the SQL. For instance, in
PostgreSQL, double quotes should surround the identifier
"""
return identifier
def visit_table(self,param):
def visit_table(self, param):
"""Rename a table; #38. Other ops aren't supported."""
table,newname = param
table, newname = param
self.start_alter_table(table)
self.append("RENAME TO %s"%newname)
self.execute()
def visit_column(self,delta):
def visit_column(self, delta):
"""Rename/change a column; #34/#35"""
# ALTER COLUMN is implemented as several ALTER statements
keys = delta.keys()
if 'type' in keys:
self._run_subvisit(delta,self._visit_column_type)
self._run_subvisit(delta, self._visit_column_type)
if 'nullable' in keys:
self._run_subvisit(delta,self._visit_column_nullable)
self._run_subvisit(delta, self._visit_column_nullable)
if 'server_default' in keys:
# Skip 'default': only handle server-side defaults, others are managed by the app, not the db.
self._run_subvisit(delta,self._visit_column_default)
# Skip 'default': only handle server-side defaults, others
# are managed by the app, not the db.
self._run_subvisit(delta, self._visit_column_default)
#if 'primary_key' in keys:
# #self._run_subvisit(delta,self._visit_column_primary_key)
# self._visit_column_primary_key(delta)
#if 'foreign_key' in keys:
# self._visit_column_foreign_key(delta)
if 'name' in keys:
self._run_subvisit(delta,self._visit_column_name)
def _run_subvisit(self,delta,func,col_name=None,table_name=None):
self._run_subvisit(delta, self._visit_column_name)
def _run_subvisit(self, delta, func, col_name=None, table_name=None):
if table_name is None:
table_name = self._to_table(delta.table)
if col_name is None:
col_name = delta.current_name
ret = func(table_name,col_name,delta)
ret = func(table_name, col_name, delta)
self.execute()
return ret
def _visit_column_foreign_key(self,delta):
def _visit_column_foreign_key(self, delta):
table = delta.table
column = getattr(table.c,delta.current_name)
cons = constraint.ForeignKeyConstraint(column,autoload=True)
column = getattr(table.c, delta.current_name)
cons = constraint.ForeignKeyConstraint(column, autoload=True)
fk = delta['foreign_key']
if fk:
# For now, cons.columns is limited to one column:
@ -178,78 +202,92 @@ class ANSISchemaChanger(AlterTableVisitor,SchemaGenerator):
column_foreign_key = None
cons.drop()
cons.create()
def _visit_column_primary_key(self,delta):
def _visit_column_primary_key(self, delta):
table = delta.table
col = getattr(table.c,delta.current_name)
col = getattr(table.c, delta.current_name)
pk = delta['primary_key']
cons = self._pk_constraint(table,col,pk)
cons = self._pk_constraint(table, col, pk)
cons.drop()
cons.create()
def _visit_column_nullable(self,table_name,col_name,delta):
def _visit_column_nullable(self, table_name, col_name, delta):
nullable = delta['nullable']
table = self._to_table(delta)
self.start_alter_table(table_name)
self.append("ALTER COLUMN %s "%self._do_quote_column_identifier(col_name))
self.append("ALTER COLUMN %s " % \
self._do_quote_column_identifier(col_name))
if nullable:
self.append("DROP NOT NULL")
else:
self.append("SET NOT NULL")
def _visit_column_default(self,table_name,col_name,delta):
def _visit_column_default(self, table_name, col_name, delta):
server_default = delta['server_default']
# Dummy column: get_col_default_string needs a column for some reason
dummy = sa.Column(None,None,server_default=server_default)
dummy = sa.Column(None, None, server_default=server_default)
default_text = self.get_column_default_string(dummy)
self.start_alter_table(table_name)
self.append("ALTER COLUMN %s "%self._do_quote_column_identifier(col_name))
self.append("ALTER COLUMN %s " % \
self._do_quote_column_identifier(col_name))
if default_text is not None:
self.append("SET DEFAULT %s"%default_text)
else:
self.append("DROP DEFAULT")
def _visit_column_type(self,table_name,col_name,delta):
def _visit_column_type(self, table_name, col_name, delta):
type = delta['type']
if not isinstance(type,sa.types.AbstractType):
if not isinstance(type, sa.types.AbstractType):
# It's the class itself, not an instance... make an instance
type = type()
#type_text = type.engine_impl(self.engine).get_col_spec()
type_text = type.dialect_impl(self.dialect).get_col_spec()
self.start_alter_table(table_name)
self.append("ALTER COLUMN %s TYPE %s"%(self._do_quote_column_identifier(col_name),type_text))
def _visit_column_name(self,table_name, col_name, delta):
self.append("ALTER COLUMN %s TYPE %s" % \
(self._do_quote_column_identifier(col_name),
type_text))
def _visit_column_name(self, table_name, col_name, delta):
new_name = delta['name']
self.start_alter_table(table_name)
self.append('RENAME COLUMN %s TO %s'%(self._do_quote_column_identifier(col_name), self._do_quote_column_identifier(new_name)))
def visit_index(self,param):
self.append('RENAME COLUMN %s TO %s' % \
(self._do_quote_column_identifier(col_name),
self._do_quote_column_identifier(new_name)))
def visit_index(self, param):
"""Rename an index; #36"""
index,newname = param
index, newname = param
#self.start_alter_table(index)
#self.append("RENAME INDEX %s TO %s"%(index.name,newname))
self.append("ALTER INDEX %s RENAME TO %s"%(index.name,newname))
self.append("ALTER INDEX %s RENAME TO %s" % (index.name, newname))
self.execute()
class ANSIConstraintCommon(AlterTableVisitor):
"""
Migrate's constraints require a separate creation function from SA's:
Migrate's constraints are created independently of a table; SA's are
created at the same time as the table.
Migrate's constraints require a separate creation function from
SA's: Migrate's constraints are created independently of a table;
SA's are created at the same time as the table.
"""
def get_constraint_name(self,cons):
def get_constraint_name(self, cons):
if cons.name is not None:
ret = cons.name
else:
ret = cons.name = cons.autoname()
return ret
class ANSIConstraintGenerator(ANSIConstraintCommon):
def get_constraint_specification(self,cons,**kwargs):
if isinstance(cons,constraint.PrimaryKeyConstraint):
def get_constraint_specification(self, cons, **kwargs):
if isinstance(cons, constraint.PrimaryKeyConstraint):
col_names = ','.join([i.name for i in cons.columns])
ret = "PRIMARY KEY (%s)"%col_names
ret = "PRIMARY KEY (%s)" % col_names
if cons.name:
# Named constraint
ret = ("CONSTRAINT %s "%cons.name)+ret
elif isinstance(cons,constraint.ForeignKeyConstraint):
ret = ("CONSTRAINT %s " % cons.name)+ret
elif isinstance(cons, constraint.ForeignKeyConstraint):
params = dict(
columns=','.join([c.name for c in cons.columns]),
reftable=cons.reftable,
@ -257,53 +295,58 @@ class ANSIConstraintGenerator(ANSIConstraintCommon):
name=self.get_constraint_name(cons),
)
ret = "CONSTRAINT %(name)s FOREIGN KEY (%(columns)s) "\
"REFERENCES %(reftable)s (%(referenced)s)"%params
elif isinstance(cons,constraint.CheckConstraint):
ret = "CHECK (%s)"%cons.sqltext
"REFERENCES %(reftable)s (%(referenced)s)" % params
elif isinstance(cons, constraint.CheckConstraint):
ret = "CHECK (%s)" % cons.sqltext
else:
raise exceptions.InvalidConstraintError(cons)
return ret
def _visit_constraint(self,constraint):
def _visit_constraint(self, constraint):
table = self.start_alter_table(constraint)
self.append("ADD ")
spec = self.get_constraint_specification(constraint)
self.append(spec)
self.execute()
def visit_migrate_primary_key_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
def visit_migrate_primary_key_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
def visit_migrate_foreign_key_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
def visit_migrate_foreign_key_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
def visit_migrate_check_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
def visit_migrate_check_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
class ANSIConstraintDropper(ANSIConstraintCommon):
def _visit_constraint(self,constraint):
def _visit_constraint(self, constraint):
self.start_alter_table(constraint)
self.append("DROP CONSTRAINT ")
self.append(self.get_constraint_name(constraint))
self.execute()
def visit_migrate_primary_key_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
def visit_migrate_primary_key_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
def visit_migrate_foreign_key_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
def visit_migrate_check_constraint(self,*p,**k):
return self._visit_constraint(*p,**k)
def visit_migrate_foreign_key_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
class ANSIFKGenerator(AlterTableVisitor,SchemaGenerator):
def visit_migrate_check_constraint(self, *p, **k):
return self._visit_constraint(*p, **k)
class ANSIFKGenerator(AlterTableVisitor, SchemaGenerator):
"""Extends ansisql generator for column creation (alter table add col)"""
def __init__(self, *args, **kwargs):
self.fk = kwargs.get('fk', None)
if self.fk:
del kwargs['fk']
super(ANSIFKGenerator, self).__init__(*args, **kwargs)
def visit_column(self,column):
def visit_column(self, column):
"""Create foreign keys for a column (table already exists); #32"""
if self.fk:
@ -312,9 +355,10 @@ class ANSIFKGenerator(AlterTableVisitor,SchemaGenerator):
if self.buffer.getvalue() !='':
self.execute()
def visit_table(self,table):
def visit_table(self, table):
pass
class ANSIDialect(object):
columngenerator = ANSIColumnGenerator
columndropper = ANSIColumnDropper
@ -322,7 +366,8 @@ class ANSIDialect(object):
columnfkgenerator = ANSIFKGenerator
@classmethod
def visitor(self,name):
return getattr(self,name)
def reflectconstraints(self,connection,table_name):
def visitor(self, name):
return getattr(self, name)
def reflectconstraints(self, connection, table_name):
raise NotImplementedError()