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Are you dead certain those projects aren't ever eating data, and nor are they about to crash tomorrow with an unrecoverably hosed DB? I still say it's bad tech

Are you dead certain those projects aren't ever eating data, and nor are they about to crash tomorrow with an unrecoverably hosed DB? I still say it's bad technology. Use plain old SQL instead.

lmm 13y ago
"plain old SQL" can require a lot of mangling one's data to fit its constraints. I refuse to believe that there isn't a better key-value store for the case where the values are json documents, even if mongodb isn't it.
- gaius 13y ago
  Except it isn't "SQL" it's first-order predicate calculus - a provably sound way to store and query your data.
- pwg 13y ago
  But if one is going to use a key-value store anyway, where is the "mangling"? Building a key-value store in an SQL database is trivial (this below is for PostgreSQL): create table keyvalue (key text, value text); create index keyvalue_idx on keyvalue(key); And use is trivial as well: insert into keyvalue (key, value) values ('key', 'value'); select value from keyvalue where key = 'key'; [edit] formatting fix.
  - lmm 13y ago
    It is not nice to have to manipulate JSON as a plain string (you miss out on validation, have to manually construct like expressions for queries, and I don't even want to think about what you'd have to do to update part of a document), at least using "plain old SQL". (PostgreSQL's native JSON support would make it quite easy, but that supports my point)
    - snaky 13y ago
      If you need to query JSON content, why to store it like plain string, to begin with? Parse it at application level (or even in stored procedure) and store like ordinary fields. Or use hstore.
      - kanja 13y ago
        Postgres additionally has a json field type.
        snaky 13y ago
        That is for now, until PostgreSQL 9.3 released, have only one useful feature comparing to plain string - validation. That's not much help, and that original lmm's point was about.
- JulianMorrison 13y ago
  Redis. Riak. Rethinkdb. Cassandra (with a mapping layer). SQL (with a mapping layer). SQL, in a JSON-typed column (PostgreSQL supports it). SQL, in a blob field, plus indexes. I could go on.

Are you dead certain those projects aren't ever eating data, and nor are they about to crash tomorrow with an unrecoverably hosed DB? I still say it's bad technology. Use plain old SQL instead.

lmm 13y ago

"plain old SQL" can require a lot of mangling one's data to fit its constraints. I refuse to believe that there isn't a better key-value store for the case where the values are json documents, even if mongodb isn't it.

gaius 13y ago
Except it isn't "SQL" it's first-order predicate calculus - a provably sound way to store and query your data.
pwg 13y ago
But if one is going to use a key-value store anyway, where is the "mangling"? Building a key-value store in an SQL database is trivial (this below is for PostgreSQL): create table keyvalue (key text, value text); create index keyvalue_idx on keyvalue(key); And use is trivial as well: insert into keyvalue (key, value) values ('key', 'value'); select value from keyvalue where key = 'key'; [edit] formatting fix.
- lmm 13y ago
  It is not nice to have to manipulate JSON as a plain string (you miss out on validation, have to manually construct like expressions for queries, and I don't even want to think about what you'd have to do to update part of a document), at least using "plain old SQL". (PostgreSQL's native JSON support would make it quite easy, but that supports my point)
  - snaky 13y ago
    If you need to query JSON content, why to store it like plain string, to begin with? Parse it at application level (or even in stored procedure) and store like ordinary fields. Or use hstore.
    - kanja 13y ago
      Postgres additionally has a json field type.
      - snaky 13y ago
        That is for now, until PostgreSQL 9.3 released, have only one useful feature comparing to plain string - validation. That's not much help, and that original lmm's point was about.
JulianMorrison 13y ago
Redis. Riak. Rethinkdb. Cassandra (with a mapping layer). SQL (with a mapping layer). SQL, in a JSON-typed column (PostgreSQL supports it). SQL, in a blob field, plus indexes. I could go on.