x/sqlalchemy-migrate
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make migrate.schema.ansisql PEP8 clean and add some sphinx docstrings

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jan.dittberner 2009-01-25 12:51:49 +00:00
parent 6e22528e6f
commit 4806e2c9e1
1 changed files with 151 additions and 106 deletions
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migrate/changeset/ansisql.py
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@ -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
At the moment, this isn't so much based off of ANSI as much as things that just things that just happen to work with multiple databases.
happen to work with multiple databases.
""" """
import sqlalchemy as sa import sqlalchemy as sa
from sqlalchemy.engine.base import Connection, Dialect from sqlalchemy.engine.base import Connection, Dialect
from sqlalchemy.sql.compiler import SchemaGenerator 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 SchemaIterator = sa.engine.SchemaIterator
class RawAlterTableVisitor(object): class RawAlterTableVisitor(object):
"""Common operations for 'alter table' statements""" """Common operations for ``ALTER TABLE`` statements."""
def _to_table(self,param):
if isinstance(param,(sa.Column,sa.Index,sa.schema.Constraint)): 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 ret = param.table
else: else:
ret = param ret = param
return ret 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) ret = self._to_table(param)
if isinstance(ret,sa.Table): if isinstance(ret, sa.Table):
ret = ret.fullname ret = ret.fullname
return ret return ret
def _do_quote_table_identifier(self, identifier): def _do_quote_table_identifier(self, identifier):
"""Returns a quoted version of the given table identifier."""
return '"%s"'%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 = self._to_table(param)
table_name = self._to_table_name(table) 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 return table
def _pk_constraint(self,table,column,status): def _pk_constraint(self, table, column, status):
"""Create a primary key constraint from a table, column """Create a primary key constraint from a table, column.
Status: true if the constraint is being added; false if being dropped Status: true if the constraint is being added; false if being dropped
""" """
if isinstance(column,basestring): if isinstance(column, basestring):
column = getattr(table.c,name) column = getattr(table.c, name)
ret = constraint.PrimaryKeyConstraint(*table.primary_key) ret = constraint.PrimaryKeyConstraint(*table.primary_key)
if status: if status:
@ -55,17 +72,16 @@ class RawAlterTableVisitor(object):
del ret.c[index] del ret.c[index]
# Allow explicit PK name assignment # Allow explicit PK name assignment
if isinstance(pk,basestring): if isinstance(pk, basestring):
ret.name = pk ret.name = pk
return ret return ret
class AlterTableVisitor(SchemaIterator,RawAlterTableVisitor):
class AlterTableVisitor(SchemaIterator, RawAlterTableVisitor):
"""Common operations for 'alter table' statements""" """Common operations for 'alter table' statements"""
from sqlalchemy.schema import ForeignKeyConstraint class ANSIColumnGenerator(AlterTableVisitor, SchemaGenerator):
class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
"""Extends ansisql generator for column creation (alter table add col)""" """Extends ansisql generator for column creation (alter table add col)"""
#def __init__(self, *args, **kwargs): #def __init__(self, *args, **kwargs):
# dialect = None # dialect = None
@ -78,7 +94,7 @@ class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
# super(ANSIColumnGenerator, self).__init__(dialect, *args, # super(ANSIColumnGenerator, self).__init__(dialect, *args,
# **kwargs) # **kwargs)
def visit_column(self,column): def visit_column(self, column):
"""Create a column (table already exists); #32""" """Create a column (table already exists); #32"""
table = self.start_alter_table(column) table = self.start_alter_table(column)
self.append(" ADD ") self.append(" ADD ")
@ -96,79 +112,87 @@ class ANSIColumnGenerator(AlterTableVisitor,SchemaGenerator):
# else: # else:
self.execute() self.execute()
def visit_table(self, table):
def visit_table(self,table):
pass pass
class ANSIColumnDropper(AlterTableVisitor): class ANSIColumnDropper(AlterTableVisitor):
"""Extends ansisql dropper for column dropping (alter table drop col)""" """Extends ANSI SQL dropper for column dropping (``ALTER TABLE
def visit_column(self,column): DROP COLUMN``)."""
def visit_column(self, column):
"""Drop a column; #33""" """Drop a column; #33"""
table = self.start_alter_table(column) 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() self.execute()
#if column.primary_key: #if column.primary_key:
# cons = self._pk_constraint(table,column,False) # cons = self._pk_constraint(table,column,False)
# cons.create() # cons.create()
class ANSISchemaChanger(AlterTableVisitor,SchemaGenerator):
class ANSISchemaChanger(AlterTableVisitor, SchemaGenerator):
"""Manages changes to existing schema elements. """Manages changes to existing schema elements.
Note that columns are schema elements; "alter table add column" is in
SchemaGenerator. 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 - All items may be renamed. Columns can also have many of their properties -
type, for example - changed. type, for example - changed.
Each function is passed a tuple, containing (object,name); where object Each function is passed a tuple, containing (object,name); where
is a type of object you'd expect for that function (ie. table for object is a type of object you'd expect for that function
visit_table) and name is the object's new name. NONE means the name is (ie. table for visit_table) and name is the object's new
unchanged. name. NONE means the name is unchanged.
""" """
def _do_quote_column_identifier(self, identifier): def _do_quote_column_identifier(self, identifier):
"""override this function to define how identifiers (table and column names) should be written in the sql. """override this function to define how identifiers (table and
for instance, in postgres, double quotes should surround the identifier column names) should be written in the SQL. For instance, in
PostgreSQL, double quotes should surround the identifier
""" """
return identifier return identifier
def visit_table(self,param): def visit_table(self, param):
"""Rename a table; #38. Other ops aren't supported.""" """Rename a table; #38. Other ops aren't supported."""
table,newname = param table, newname = param
self.start_alter_table(table) self.start_alter_table(table)
self.append("RENAME TO %s"%newname) self.append("RENAME TO %s"%newname)
self.execute() self.execute()
def visit_column(self,delta): def visit_column(self, delta):
"""Rename/change a column; #34/#35""" """Rename/change a column; #34/#35"""
# ALTER COLUMN is implemented as several ALTER statements # ALTER COLUMN is implemented as several ALTER statements
keys = delta.keys() keys = delta.keys()
if 'type' in 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: 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: if 'server_default' in keys:
# Skip 'default': only handle server-side defaults, others are managed by the app, not the db. # Skip 'default': only handle server-side defaults, others
self._run_subvisit(delta,self._visit_column_default) # are managed by the app, not the db.
self._run_subvisit(delta, self._visit_column_default)
#if 'primary_key' in keys: #if 'primary_key' in keys:
# #self._run_subvisit(delta,self._visit_column_primary_key) # #self._run_subvisit(delta,self._visit_column_primary_key)
# self._visit_column_primary_key(delta) # self._visit_column_primary_key(delta)
#if 'foreign_key' in keys: #if 'foreign_key' in keys:
# self._visit_column_foreign_key(delta) # self._visit_column_foreign_key(delta)
if 'name' in keys: if 'name' in keys:
self._run_subvisit(delta,self._visit_column_name) self._run_subvisit(delta, self._visit_column_name)
def _run_subvisit(self,delta,func,col_name=None,table_name=None):
def _run_subvisit(self, delta, func, col_name=None, table_name=None):
if table_name is None: if table_name is None:
table_name = self._to_table(delta.table) table_name = self._to_table(delta.table)
if col_name is None: if col_name is None:
col_name = delta.current_name col_name = delta.current_name
ret = func(table_name,col_name,delta) ret = func(table_name, col_name, delta)
self.execute() self.execute()
return ret return ret
def _visit_column_foreign_key(self,delta): def _visit_column_foreign_key(self, delta):
table = delta.table table = delta.table
column = getattr(table.c,delta.current_name) column = getattr(table.c, delta.current_name)
cons = constraint.ForeignKeyConstraint(column,autoload=True) cons = constraint.ForeignKeyConstraint(column, autoload=True)
fk = delta['foreign_key'] fk = delta['foreign_key']
if fk: if fk:
# For now, cons.columns is limited to one column: # For now, cons.columns is limited to one column:
@ -178,78 +202,92 @@ class ANSISchemaChanger(AlterTableVisitor,SchemaGenerator):
column_foreign_key = None column_foreign_key = None
cons.drop() cons.drop()
cons.create() cons.create()
def _visit_column_primary_key(self,delta):
def _visit_column_primary_key(self, delta):
table = delta.table table = delta.table
col = getattr(table.c,delta.current_name) col = getattr(table.c, delta.current_name)
pk = delta['primary_key'] pk = delta['primary_key']
cons = self._pk_constraint(table,col,pk) cons = self._pk_constraint(table, col, pk)
cons.drop() cons.drop()
cons.create() 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'] nullable = delta['nullable']
table = self._to_table(delta) table = self._to_table(delta)
self.start_alter_table(table_name) 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: if nullable:
self.append("DROP NOT NULL") self.append("DROP NOT NULL")
else: else:
self.append("SET NOT NULL") 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'] server_default = delta['server_default']
# Dummy column: get_col_default_string needs a column for some reason # 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) default_text = self.get_column_default_string(dummy)
self.start_alter_table(table_name) 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: if default_text is not None:
self.append("SET DEFAULT %s"%default_text) self.append("SET DEFAULT %s"%default_text)
else: else:
self.append("DROP DEFAULT") 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'] 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 # It's the class itself, not an instance... make an instance
type = type() type = type()
#type_text = type.engine_impl(self.engine).get_col_spec() #type_text = type.engine_impl(self.engine).get_col_spec()
type_text = type.dialect_impl(self.dialect).get_col_spec() type_text = type.dialect_impl(self.dialect).get_col_spec()
self.start_alter_table(table_name) self.start_alter_table(table_name)
self.append("ALTER COLUMN %s TYPE %s"%(self._do_quote_column_identifier(col_name),type_text)) self.append("ALTER COLUMN %s TYPE %s" % \
def _visit_column_name(self,table_name, col_name, delta): (self._do_quote_column_identifier(col_name),
type_text))
def _visit_column_name(self, table_name, col_name, delta):
new_name = delta['name'] new_name = delta['name']
self.start_alter_table(table_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))) 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): def visit_index(self, param):
"""Rename an index; #36""" """Rename an index; #36"""
index,newname = param index, newname = param
#self.start_alter_table(index) #self.start_alter_table(index)
#self.append("RENAME INDEX %s TO %s"%(index.name,newname)) #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() self.execute()
class ANSIConstraintCommon(AlterTableVisitor): class ANSIConstraintCommon(AlterTableVisitor):
""" """
Migrate's constraints require a separate creation function from SA's: Migrate's constraints require a separate creation function from
Migrate's constraints are created independently of a table; SA's are SA's: Migrate's constraints are created independently of a table;
created at the same time as the 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: if cons.name is not None:
ret = cons.name ret = cons.name
else: else:
ret = cons.name = cons.autoname() ret = cons.name = cons.autoname()
return ret return ret
class ANSIConstraintGenerator(ANSIConstraintCommon): 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]) 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: if cons.name:
# Named constraint # Named constraint
ret = ("CONSTRAINT %s "%cons.name)+ret ret = ("CONSTRAINT %s " % cons.name)+ret
elif isinstance(cons,constraint.ForeignKeyConstraint): elif isinstance(cons, constraint.ForeignKeyConstraint):
params = dict( params = dict(
columns=','.join([c.name for c in cons.columns]), columns=','.join([c.name for c in cons.columns]),
reftable=cons.reftable, reftable=cons.reftable,
@ -257,53 +295,58 @@ class ANSIConstraintGenerator(ANSIConstraintCommon):
name=self.get_constraint_name(cons), name=self.get_constraint_name(cons),
) )
ret = "CONSTRAINT %(name)s FOREIGN KEY (%(columns)s) "\ ret = "CONSTRAINT %(name)s FOREIGN KEY (%(columns)s) "\
"REFERENCES %(reftable)s (%(referenced)s)"%params "REFERENCES %(reftable)s (%(referenced)s)" % params
elif isinstance(cons,constraint.CheckConstraint): elif isinstance(cons, constraint.CheckConstraint):
ret = "CHECK (%s)"%cons.sqltext ret = "CHECK (%s)" % cons.sqltext
else: else:
raise exceptions.InvalidConstraintError(cons) raise exceptions.InvalidConstraintError(cons)
return ret return ret
def _visit_constraint(self,constraint):
def _visit_constraint(self, constraint):
table = self.start_alter_table(constraint) table = self.start_alter_table(constraint)
self.append("ADD ") self.append("ADD ")
spec = self.get_constraint_specification(constraint) spec = self.get_constraint_specification(constraint)
self.append(spec) self.append(spec)
self.execute() self.execute()
def visit_migrate_primary_key_constraint(self,*p,**k): def visit_migrate_primary_key_constraint(self, *p, **k):
return self._visit_constraint(*p,**k) return self._visit_constraint(*p, **k)
def visit_migrate_foreign_key_constraint(self,*p,**k): def visit_migrate_foreign_key_constraint(self, *p, **k):
return self._visit_constraint(*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): class ANSIConstraintDropper(ANSIConstraintCommon):
def _visit_constraint(self,constraint):
def _visit_constraint(self, constraint):
self.start_alter_table(constraint) self.start_alter_table(constraint)
self.append("DROP CONSTRAINT ") self.append("DROP CONSTRAINT ")
self.append(self.get_constraint_name(constraint)) self.append(self.get_constraint_name(constraint))
self.execute() self.execute()
def visit_migrate_primary_key_constraint(self,*p,**k): def visit_migrate_primary_key_constraint(self, *p, **k):
return self._visit_constraint(*p,**k) return self._visit_constraint(*p, **k)
def visit_migrate_foreign_key_constraint(self,*p,**k): def visit_migrate_foreign_key_constraint(self, *p, **k):
return self._visit_constraint(*p,**k) return self._visit_constraint(*p, **k)
def visit_migrate_check_constraint(self,*p,**k): def visit_migrate_check_constraint(self, *p, **k):
return self._visit_constraint(*p,**k) return self._visit_constraint(*p, **k)
class ANSIFKGenerator(AlterTableVisitor,SchemaGenerator):
class ANSIFKGenerator(AlterTableVisitor, SchemaGenerator):
"""Extends ansisql generator for column creation (alter table add col)""" """Extends ansisql generator for column creation (alter table add col)"""
def __init__(self, *args, **kwargs): def __init__(self, *args, **kwargs):
self.fk = kwargs.get('fk', None) self.fk = kwargs.get('fk', None)
if self.fk: if self.fk:
del kwargs['fk'] del kwargs['fk']
super(ANSIFKGenerator, self).__init__(*args, **kwargs) 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""" """Create foreign keys for a column (table already exists); #32"""
if self.fk: if self.fk:
@ -312,9 +355,10 @@ class ANSIFKGenerator(AlterTableVisitor,SchemaGenerator):
if self.buffer.getvalue() !='': if self.buffer.getvalue() !='':
self.execute() self.execute()
def visit_table(self,table): def visit_table(self, table):
pass pass
class ANSIDialect(object): class ANSIDialect(object):
columngenerator = ANSIColumnGenerator columngenerator = ANSIColumnGenerator
columndropper = ANSIColumnDropper columndropper = ANSIColumnDropper
@ -322,7 +366,8 @@ class ANSIDialect(object):
columnfkgenerator = ANSIFKGenerator columnfkgenerator = ANSIFKGenerator
@classmethod @classmethod
def visitor(self,name): def visitor(self, name):
return getattr(self,name) return getattr(self, name)
def reflectconstraints(self,connection,table_name):
def reflectconstraints(self, connection, table_name):
raise NotImplementedError() raise NotImplementedError()