entity-attribute-value

from django.db import models # django user from django.contrib.auth.models import User class Entity(models.Model): """ Entity of EAV """ entity = models.CharField(max_length=216, null=False, default='entity_name', name='entity', verbose_name='Entity of EAV', db_index=True, unique=True ) class Asset(models.Model): """ Asset of EAV """ asset = models.CharField(max_length=216, null=False, default='asset', name='asset', verbose_name='Asset of EAV' ) entity = models.ForeignKey(to=Entity) class Meta: unique_together = ("asset", "entity") class Value(models.Model): """ Value of EAV """ value = models

Let's ask the question clearly before entering into the details: Is there a way of hard deleting an attribute value from a product? By hard I mean, removing the row from the database and not only setting the value to null or empty. Now, the details: I'm currently confronted to a problem on Magento. Many product in my store have user defined attributes that are not related to the product. For example, let's say we have a bag product, among other products like t-shirts,dresses,pants ,etc.: Our bag product has only configurable 1 attribute: color . Our T-Shirt product has 2 configurable

I have three tables: components , attributes and attribute_values . Each component can have many attribute_values . Each attribute_value belongs to one attribute . Yeah, it's the dreaded EAV pattern... I have created these two forms: class AttributeValueForm(Form): attribute = HiddenField() value = StringField('Value') class ComponentForm(Form): ... non-related fields left out ... attribute_values = FieldList(FormField(AttributeValueForm)) These are the SQLAlchemy models: class Component(db.Model): __tablename__ = 'components' id = db.Column(db.Integer, primary_key=True) ... non-related

I have a table like below which would have the product description ╔════╦══════════════╦══════╗ ║ Id ║ name ║ price║ ╠════╬══════════════╬══════╣ ║ 1 ║ Apple ║ 23 ║ ║ 2 ║ shirt ║ 148 ║ ║ 3 ║ computer ║ 101 ║ ║ 4 ║ printer ║ 959 ║ ╚════╩══════════════╩══════╝ and another table which is holding the attributes like linked by the ID ╔════╦══════════════╦══════╗ ║ Id ║ attr_name ║ Value║ ╠════╬══════════════╬══════╣ ║ 1 ║ color ║ red ║ ║ 1 ║ size ║ xl ║ ║ 1 ║ brand ║ App ║ ║ 2 ║ color ║ blue║ ║ 2 ║ size ║ l ║ ║ 3 ║ color ║ blue║ ║ 3 ║ size ║ xxl ║ ║ 3 ║ brand ║ HP ║ ╚════╩══════════════╩══════╝ Is

I am currently working to rework the data system of our application. Basically, it is designed so that people can add all the custom fields they want, with only a few constant/always-there fields. Our current design is giving us plenty of maintenance problems. What we do is dynamically(at runtime) add a column to the database for each field. We have to have a meta table and other cruft to maintain all of these dynamic columns. Now we are looking at EAV, but it doesn't seem much better. Basically, we have many different types of fields, so there would be a StringValues, IntegerValues, etc table

I am developing a stock control system for a construction project. The storeman is responsible for adding new stock and distributing/returning it to/from employees. The items (and hence their attributes) will be very varied; e.g. steelwork, clothing, plant/machinery, tools, etc. My question is whether to go for a Class/Concrete Table Inheritance or EAV based schema. I don't know what attributes items will have, so presumably a Class/Concrete Table Inheritance approach would require the end user to add new tables to the database (is this possible?). Please see my proposed EAV schema . Would