1 .. _renamehowto:

     2 

     3 

     4 How to rename classes of existing objects

     5 =========================================

     6 

     7 

     8 When you develop new features to PyAMS we sometimes have to rename or modify classes of already stored objects if you do

     9 that you will never access yours objects. But PyAMS provides `zodbupdate` script to update easily update the change in ZODB.

    10 

    11 

    12 **1) Include you package in the require resource for you webapp**

    13 

    14 

    15 .. code-block:: python

    16 

    17     requires = [

    18         'mypackage',

    19         ...

    20     ]

    21 

    22 **2) Add the Entry points**

    23 

    24 

    25 In the `setup.py` file add 'zodbupdate' params into entry_points where is store zodbupdate directives

    26 

    27 .. code-block:: python

    28 

    29       entry_points={

    30           'zodbupdate': [

    31               'renames = mypackage.generations:RENAMED_CLASSES'

    32           ]

    33       }

    34 

    35 

    36 

    37 **3) Create a module named** ``generation`` **with the migration directives**

    38 

    39 

    40 .. code-block:: python

    41 

    42     RENAMED_CLASSES = {

    43         'mypackage.mymodule MyOldClass': 'mypackage.mymodule MyNewClass'

    44     }

    45 

    46 

    47 **4) Run the commands** ``buildout`` .

    48 

    49 .. code-block:: console

    50 

    51     $ mypackage/bin/buildout

    52     $ webapp/bin/buildout

    53 

    54 

    55 The ``buildout`` command going to install correctly the package and add the new entry_points references in entry_points.txt

    56 

    57 **5)  Run the commands** ``zodbupdate``

    58 

    59 To finish run `zodbupdate` to apply the changes describe in `RENAMED_CLASSES`

    60 

    61 .. code-block:: console

    62 

    63     $   bin/zodbupdate --config etc/zodbupdate-zeo.conf

    64 

    65 

    66 Where `zodbupdate-zeo.conf` is the configuration file to access to the ZODB.