4 ms·

I think it's pretty clear to anyone who's used it. It allows for rapid, low overhead changes to your data model in the very early stages of building something

by base698 14y ago

I think it's pretty clear to anyone who's used it. It allows for rapid, low overhead changes to your data model in the very early stages of building something new. Of course, the further along you get those changes are no longer low overhead, but at the start of the new project it's very easy to get up and running.

gtaylor 14y ago
I guess I just don't find schema that big a deal even in the early goings. A relational DB schema isn't necessarily hard to change and adapt on the fly. I don't feel like this is the best thing for Mongo to hang its hat on, and I'm not sure they really are. I think its users tend to point at this as a big feature more than they should. I feel like the other reasons to use Mongo should show up more in these discussions than this "It's easy to make schema changes". Perhaps these are easier scaling/sharding, I don't know, I don't use Mongo. I just see the schema part of this as a sidepoint (albeit an important one from an application design perspective). There are legitimate cases where supremely simple schema flexibility is desirable, but I suspect a lot of people who think they need this really don't (there are easy ways to do this with relational DBs), and are in fact making some things more complicated as a result. While it IS very easy to change your schema with Mongo, let's not forget that you're going to need to enforce certain schema-related rules in your codebase instead of the DB now.
pkulak 14y ago
At the start of a project it's also really easy to change an SQL schema.
- gtaylor 14y ago
  This. I don't understand why this isn't mentioned more often. Developer convenience and productivity are important things, but the future integrity of your application shouldn't be compromised for either. There are legitimate usage cases for a non-relational document store like MongoDB, but I suspect there are a non-trivial number of people using it that would be better served by a relational DB. Or even something like Postgres that has both relational and non-relational capabilities.
- base698 14y ago
  It's not easier than nothing. You don't have to do ANYTHING in mongo. In any reasonable sized web app with a well designed ERD changing is going to result in you stopping coding and doing some ALTER TABLE, DROP INDEX, etc commands before you can start back with the coding. Also when you want to create a report you can just write a script aggregates the data and fills another collection on the fly without creating the table first. You can even try out 6 different reports at the same time, without issuing separate create table statements.
  - gregjor 14y ago
    QED.
- gregjor 14y ago
  It's easy to change a relational schema if you understand relational databases. If you don't then Mongo et al. look like good ideas because they solve an actual developer problem: ignorance.
  - rimantas 14y ago
    Making problem less visible (for a while) is hardly a solution.

by base698 14y ago

gtaylor 14y ago

I guess I just don't find schema that big a deal even in the early goings. A relational DB schema isn't necessarily hard to change and adapt on the fly. I don't feel like this is the best thing for Mongo to hang its hat on, and I'm not sure they really are. I think its users tend to point at this as a big feature more than they should. I feel like the other reasons to use Mongo should show up more in these discussions than this "It's easy to make schema changes". Perhaps these are easier scaling/sharding, I don't know, I don't use Mongo. I just see the schema part of this as a sidepoint (albeit an important one from an application design perspective). There are legitimate cases where supremely simple schema flexibility is desirable, but I suspect a lot of people who think they need this really don't (there are easy ways to do this with relational DBs), and are in fact making some things more complicated as a result. While it IS very easy to change your schema with Mongo, let's not forget that you're going to need to enforce certain schema-related rules in your codebase instead of the DB now.

pkulak 14y ago

At the start of a project it's also really easy to change an SQL schema.

gtaylor 14y ago
This. I don't understand why this isn't mentioned more often. Developer convenience and productivity are important things, but the future integrity of your application shouldn't be compromised for either. There are legitimate usage cases for a non-relational document store like MongoDB, but I suspect there are a non-trivial number of people using it that would be better served by a relational DB. Or even something like Postgres that has both relational and non-relational capabilities.
base698 14y ago
It's not easier than nothing. You don't have to do ANYTHING in mongo. In any reasonable sized web app with a well designed ERD changing is going to result in you stopping coding and doing some ALTER TABLE, DROP INDEX, etc commands before you can start back with the coding. Also when you want to create a report you can just write a script aggregates the data and fills another collection on the fly without creating the table first. You can even try out 6 different reports at the same time, without issuing separate create table statements.
- gregjor 14y ago
  QED.
gregjor 14y ago
It's easy to change a relational schema if you understand relational databases. If you don't then Mongo et al. look like good ideas because they solve an actual developer problem: ignorance.
- rimantas 14y ago
  Making problem less visible (for a while) is hardly a solution.