# YOPA

Yopa is a relational database for cataloging things.

The data model is user-editable through a web interface, together with the data.

## Data model

There are three kinds of entities in the database: objects, relations, and properties.

Here is an example database schema that can be easily set up in Yopa:

```
      ,----quantity-----> Ingredient
      |                   - amount in the pantry
      |                   - e-shop link
      |
Recipe ------page X-----> Book
- cook time               - author(s)
- difficulty              - year
- photo URI(s)
```

Relations link two objects. Properties are attached either to an object, or to a 
relation - this makes sense for relations that need additional information, such as a 
page number when referencing a book.

Yopa implements four base data types: String, Integer, Decimal and Boolean. Properties 
may further be optional and/or multiple.

## Web interface

Yopa is the database engine. There can be any number of user interfaces to it. Presently,
the `yopa-web` module provides a web interface with a built-in web server. Just run the 
binary and it will open your yopa database for editing. The file is created on the first
change if it doesn't exist.