Maybe you need to use the Doctrine’s command line while you are developing a Symfony Bundle (or anything else).
This will make you able, for example, to validate the schema or to convert an annotated schema to its XML counterpart.
Here is how to use Doctrine command line outside of a Symfony Application.
I was thinking about some entities I need, when I came across a very interesting concept: Immutable Objects.
The Immutable Objects are very handy to manage the so called Value Objects.
In the Domain Driven Design (DDD) properties of an Entity can have two different values: other Entities (Order->getProduct() – here Product is an Entity and its properties can change) or simple values (Product->getPrice()).
Price, in our example, is a simple value, not conceptually an Entity. Until now, it probably is a simple property in your Entities (as it was in mine!).
But, in this second case, the Value Objects play their parts: they represent those values in an immutable state.
In fact, if you reflect about the data Price , you realize that a Price is something like “100 Eur”. If you put your attention on the value, you can recognize more than one smaller parts in it: a numeric value – 100 – and a string value – Eur.
A Price is a Price only if we indicate both the numeric part of it (100) and the string part of it (Eur): If we indicate only one of the two, it is not a Price because we don’t know how much money does it represents or in which currency the price is expressed.
So we need both the “amount” and the “currency” to have a real value. Think it as a “composite value”.
And the important thing to consider to understand what Immutable stands for: if in the Price we change the amount, we have a different price. If in the Price we change the currency, we have, again, a different price.
But if in a Product we change the Price, we don’t have a different Product but the same one with only a different Price.
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