peeweedbevolve.py 文件源码

def change_column_type(db, migrator, table_name, column_name, field):
  qc = db.compiler()
  column_type = qc.get_column_type(field.get_db_field())
  if is_postgres(db):
    op = pw.Clause(pw.SQL('ALTER TABLE'), pw.Entity(table_name), pw.SQL('ALTER'), field.as_entity(), pw.SQL('TYPE'), field.__ddl_column__(column_type))
  elif is_mysql(db):
    op = pw.Clause(*[pw.SQL('ALTER TABLE'), pw.Entity(table_name), pw.SQL('MODIFY')] + field.__ddl__(column_type))
  else:
    raise Exception('how do i change a column type for %s?' % db)
  return normalize_whatever_junk_peewee_migrations_gives_you(db, migrator, op)