Database Layer

The database layer (db) is a very thin layer that contains exactly how the data is stored in the underlying database system.

It involves concepts like:

• Schema
• Tables
• Columns
• Primary and foreign keys

Here is an example of a table definition in VKL:

db.postgres.movie_db.public {
    table ORDERS {
        identifier: "ORDERS"
        
        column id {
            primitive_type: "INTEGER"
            identifier: "id"
            is_primary_key: true
        }

        column customer_id {
            primitive_type: "INTEGER"
            identifier: "customer_id"
        }

        column customer_firstname {
            primitive_type: "VARCHAR"
            identifier: "customer_firstname"
        }

        column customer_lastname {
            primitive_type: "VARCHAR"
            identifier: "customer_lastname"
        }            
        
        column country {
            primitive_type: "VARCHAR"
            identifier: "country"
        }
        
        column date {
            primitive_type: "DATE"
            identifier: "date"
        }
        ...
    }
}

The identifier is a SQL identifier, i.e. a column/table/schema/database name. These identifiers are used by Veezoo to generate SQL code.

Let's see what's next.