Add pinyin mnemonic support to a model

如果希望在单据或者数据列表页面，可以用拼音首字母来搜索供应商、产品、客户等，可以使用下面的方法，增加这个功能。

• Add field mnemonic to the model with type string as below

mnemonic = Column(String(64), unique=False, nullable=True)

• Generate DB migrate using follow command in the project root folder

python manage.py db migrate

• Add event listener in psi/app/models/aspect.py as below

# Customer is the model name
@event.listens_for(Customer, 'before_insert')
@event.listens_for(Customer, 'before_update')

• If you just like to use "name" field as the mnemonic source, then that's done, if you would like to use a custom mnemonic, then you can implement method get_value_for_mnemonic in the model definition, for example

# Use field last_name and first_name as source of the mnemonic.
def get_value_for_mnemonic(self):
    return get_name(self.last_name, self.first_name)

• Samples in the code

# models/Customer.py
# models/Supplier.py
# models/Product.py