def do_rename(self, change):
try:
sql = SQL()
sql.extend(self.ops.get_change_table_name_sql(change.left, change.right))
if change.nested:
commands = [(change, sql)]
commands.extend(self.do_try_update(change))
return commands
except RebuildTableNeededException:
return self.do_rebuild(change)
return sql
def get_rebuild_table_sql(self, left, right, renames):
"""
Renames: right => left
"""
old_names = left.fields.keys()
#print "Renames:", renames
# used instead of column renames, additions and removals
qn = self.connection.ops.quote_name
kw = self.style.SQL_KEYWORD
fld = self.style.SQL_FIELD
tqn = lambda s: self.style.SQL_TABLE(qn(s))
fqn = lambda s: self.style.SQL_FIELD(qn(s))
fqv = lambda s: self.style.SQL_FIELD(self.quote_value(s))
sql = SQL('-- FYI: next few lines could take a while if you have a lot of data')
tmp_table_name = right.name + '_1337_TMP' # unlikely to produce a namespace conflict
temp = DBTable(tmp_table_name)
sql.extend(self.get_change_table_name_sql(left, temp))
sql.extend(self.get_create_table_sql(right))
updated = []
for f in right.fields.values():
if f.name in renames:
updated.append(fqn(renames[f.name])) # copy renamed column
elif f.name in old_names:
updated.append(fqn(f.name)) # copy column
else:
default = NotProvided
if f.allow_null:
default = None
elif f.primary_key:
default = '0'
elif f.coltype.coltype in ['int', 'bool', 'tinyint']:
default = '0'
elif f.coltype.coltype in ['varchar', 'text']:
default = ''
default = get_field_default(f, default) # add column with default value set
if default is None:
updated.append('NULL')
else:
updated.append(fqv(default))
sql.append(kw('INSERT INTO ') +
tqn(right.name) +
kw(' SELECT ') +
fld(','.join(updated)) +
kw(' FROM ') +
tqn(tmp_table_name) +';')
sql.extend(self.get_drop_table_sql(temp))
sql.extend(self.get_create_table_indexes_sql(right))
return sql
def get_create_table_indexes_sql(self, table):
sql = SQL()
for index in table.indexes.values():
sql.extend(self.get_create_index_sql(table, index))
return sql
