5 ms·

Having written a non-ORM Go-Postgres tool [1] similar to sqlc, I'm a big fan of this article, especially their acknowledgment that using SQL moves the eng cultu

by sa46 5y ago

Having written a non-ORM Go-Postgres tool [1] similar to sqlc, I'm a big fan of this article, especially their acknowledgment that using SQL moves the eng culture towards data-centric engineering. Some thoughts: - Application code should not rely on database table structure (like the ActiveRecord pattern). Modeling the database as a bunch of queries is a better bet since you can change the underlying table structure but keep the same query semantics to allow for database refactoring. - Database code and queries should be defined in SQL. I'm not a fan of defining the database in another programming language that generates DDL for you since it's another layer of abstraction that usually leaks heavily. - One of the main drawbacks of writing queries in plain SQL is that dynamic queries are more difficult to write. I haven't found that to be too much of a problem since you can use multiple queries or push some of the dynamic parts into a SQL predicate. Some things are easier with an ORM, like dynamic ordering or dynamic group-by clauses. [1]: https://github.com/jschaf/pggen https://github.com/jschaf/pggen Similar comment from a few months ago comparing Go approaches to SQL: https://news.ycombinator.com/item?id=28463938 https://news.ycombinator.com/item?id=28463938

zzzeek 5y ago
say your application has 120 tables. Do you write out 120 "INSERT" statements, 120 "UPDATE" statements, 120 "DELETE" statements as raw strings or otherwise every time you need to do any DML ? if not, and instead you have something that dynamically writes these out given some kind of object state to persist, you are using an ORM. similarly, when you transfer the states of structures and/or objects to those INSERT/UPDATE/DELETE statements, or the rows from the cursor execution of a SELECT statement into object/structural state, that is also using an ORM. I tend to consider "a query builder that writes SELECT statements" to be the least important thing an "ORM" can do, and is not even necessary to still have a library defined as an ORM. The "mapping" is mostly to do with automating the movement of data between the objects / database, which is, the relational tuples mapped to object attributes.
- sa46 5y ago
  > Do you write out 120 "INSERT" statements, 120 "UPDATE" statements, 120 "DELETE" statements as raw strings Yes. For example: https://github.com/jschaf/pggen/blob/main/example/erp/order/customer.sql https://github.com/jschaf/pggen/blob/main/example/erp/order/.... > that is also using an ORM ORM as a term covers a wide swathe of usage. In the smallest definition, an ORM converts DB tuples to Go structs. In common usage, most folks use ORM to mean a generic query builder plus the type conversion from tuples to structs. For other usages, I prefer the Patterns of Enterprise Application Architecture terms [1] like data-mapper, active record, and table-data gateway. [1]: https://martinfowler.com/eaaCatalog/ https://martinfowler.com/eaaCatalog/
  - zzzeek 5y ago
    yes, I do also: https://techspot.zzzeek.org/2012/02/07/patterns-implemented-by-sqlalchemy/ https://techspot.zzzeek.org/2012/02/07/patterns-implemented-...

by sa46 5y ago

zzzeek 5y ago

say your application has 120 tables. Do you write out 120 "INSERT" statements, 120 "UPDATE" statements, 120 "DELETE" statements as raw strings or otherwise every time you need to do any DML ? if not, and instead you have something that dynamically writes these out given some kind of object state to persist, you are using an ORM. similarly, when you transfer the states of structures and/or objects to those INSERT/UPDATE/DELETE statements, or the rows from the cursor execution of a SELECT statement into object/structural state, that is also using an ORM. I tend to consider "a query builder that writes SELECT statements" to be the least important thing an "ORM" can do, and is not even necessary to still have a library defined as an ORM. The "mapping" is mostly to do with automating the movement of data between the objects / database, which is, the relational tuples mapped to object attributes.

sa46 5y ago
> Do you write out 120 "INSERT" statements, 120 "UPDATE" statements, 120 "DELETE" statements as raw strings Yes. For example: https://github.com/jschaf/pggen/blob/main/example/erp/order/customer.sql https://github.com/jschaf/pggen/blob/main/example/erp/order/.... > that is also using an ORM ORM as a term covers a wide swathe of usage. In the smallest definition, an ORM converts DB tuples to Go structs. In common usage, most folks use ORM to mean a generic query builder plus the type conversion from tuples to structs. For other usages, I prefer the Patterns of Enterprise Application Architecture terms [1] like data-mapper, active record, and table-data gateway. [1]: https://martinfowler.com/eaaCatalog/ https://martinfowler.com/eaaCatalog/
- zzzeek 5y ago
  yes, I do also: https://techspot.zzzeek.org/2012/02/07/patterns-implemented-by-sqlalchemy/ https://techspot.zzzeek.org/2012/02/07/patterns-implemented-...