Business Layer

[ghost]

Creating an Abstraction Layer between Model and Db ? How ? Usefulnesses ?

[blablanumerodeux]

Is an API a data access layer ?
Or there is another thing called data access layer ?
Do you mean an ORM like hibernate but for nodejs ?

[ghost]

Data Access Layer is an Abstraction Layer :

• It allows to create business Objects with the same properties that our Model Objects
• It defines the Business Logic ("la couche métier")
• It is another layer to check values before DB operations

Until there, you may say "Oh, but it is our Model Layer so what for creating a such layer ?"

In fact, a Data Access Layer is really useful for :

• Tests : it's a pipe where in input you give parameters, in output you test what it's returned and in the middle (in the pipe), you use the functions of the Business Object
• It's a real way to separate the model and web layer from the database
• This layer can be used on every platform : using a web application, a winform or whatever (like an API)

For our project, this DAL is not compulsory but it will help us to test easily our functions to query to the database

[blablanumerodeux]

Okay, I see, at my work we use DAOs (Data Access Objects) to do exactly what you say, so I presume that all these DAO together are creating a DAL...
So now I really see the point of a DAL.
And we can surely make this.
👍