toucan2.query — io.github.camsaul/toucan2 1.0.0-beta2-SNAPSHOT

Query compilation pipeline is something like this:

Call something like [[toucan2.select/select]] with `modelable` and `unparsed-args`
↓
`modelable` is resolved to `model` with [[toucan2.model/with-model]]
↓
[[parse-args]] is used to parse args into a `parsed-args` map
↓
The `:queryable` key in parsed args is resolved
↓
[[build]] takes the resolved query and combines the other parsed args into it to build a compilable query. The default
backend builds a Honey SQL 2 query map
↓
some sort of reducible is returned.

<reducing the reducible>
↓
[[toucan2.compile/with-compiled-query]] compiles the built query (e.g. Honey SQL 2) into something that can be
executed natively (e.g. a `sql-args` vector)
↓
[[toucan2.connection/with-connection]] is used to get a connection from the current connectable, or the default
connectable for `model`, or the global default connectable
↓
Compiled query is executed with connection

apply-kv-arg clj

(apply-kv-arg model₁ query₂ k₃ v)

apply-kv-args clj

(apply-kv-args model query kv-args)

condition->honeysql-where-clause clj

(condition->honeysql-where-clause k v)

Something sequential like :id [:> 5] becomes [:> :id 5]. Other stuff like :id 5 just becomes [:= :id 5].

honeysql-table-and-alias clj

(honeysql-table-and-alias model)

Build an Honey SQL [table] or [table alias] (if the model has a toucan2.model/namespace form) for model for use in something like a :select clause.

parse-args clj

(parse-args query-type unparsed-args)

(parse-args query-type spec unparsed-args)

parse-args takes a sequence of unparsed args passed to something like toucan2.select/select and parses them into a parsed args map. The default implementation uses [[clojure.spec.alpha]] to parse the args according to args-spec.

These keys are commonly returned by several of the different implementations parse-args, and other tooling is build to leverage them:

• :modelable -- usually the first of the unparsed-args, this is the thing that should get resolved to a model with toucan2.model/with-model.

• :queryable -- something that can be resolved to a query, for example a map or integer or 'named query' keyword. The resolved query is ultimately combined with other parsed args and built into something like a Honey SQL map with [[build]], then compiled with toucan2.compile/with-compiled-query.

• :kv-args -- map of key-value pairs. When [[build]] builds a query, it calls apply-kv-arg for each of the key-value pairs. The default behavior is to append a Honey SQL :where clause based on the pair; but you can customize the behavior for specific keywords to do other things -- :toucan/pk is one such example.

• :columns -- for things that return instances, :columns is a sequence of columns to return. These are commonly specified by wrapping the modelable in a [modelable & columns] vector.

validate-parsed-args clj

(validate-parsed-args parsed-args)