graphback
graphback copied to clipboard
aerogear
[Migrations] Ability to specify "CHECK" constraints and Auto-add them "CHECK" for enum types
/cc @craicoverflow, @wtrocki Automatically generated comment to notify maintainers
Is it possible to add a check constraint to enum database types? I know very little about them, but I could not find anything about adding a CHECK constraint to a database enum.
The idea will be to check that the string is within the given enumeration values CHECK IN (....).
Ah, in that case this seems sensible. Would it be better to map enums to database enums instead?
Not sure if that will work across different relational database, SQLite, MySQL etc. But worth a separate discussion.
cc @machi1990 can you add more info, maybe with the new issue template?
SQL has check constraints e.g https://www.postgresql.org/docs/9.4/ddl-constraints.html which automatically verifies the valid of data under the given constraints.
With this feature we'll be looking to support defining them via an annotation, let me call it @db(check: []).
Taking the products table from the shared link above, this could then be modeled as:
@model
@db(name: 'products')
type Product {
"""
@id
"""
product_no: ID!
name: String,
"""
@db(check: ['price > 0'])
"""
price: ID
}
The constraint can be named too, and in this case:
@model
@db(name: 'products')
type Product {
"""
@id
"""
product_no: ID!
name: String,
"""
@db(check: [{name: 'positive_price', constraint: 'price > 0' }])
"""
price: ID
}
can be applied to several fields, where a declaration can refer to another field.
@model
@db(name: 'products')
type Product {
"""
@id
"""
product_no: ID!
name: String,
"""
@db(check: [{name: 'positive_price', constraint: 'price > 0' }])
"""
price: ID
"""
@db(check: ['discounted_price > 0', 'price > discounted_price'])
"""
discounted_price: ID
}
The "check in" constraint can be applied to enum type for database that do not support them e.g SQLite.
Does something like that make sense and we'll want to support?