Struct Query

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pub struct Query { /* private fields */ }

Expand description

A Query is a special kind of body that we submit to the query function. It has the following fields:

find is responsible for defining which elements of the query you want shown in the response, it is required. Argument is a vector with elements to be queried, vec!["a", "b", "c"]. It is parsed as :find [a b c], qhere a, b, c are the elements defined in where clause.
where_clause is responsible for defining which rules will be applied to filter elements, it is required. Argument is a vector with the strings containing the filtering function, vec!["a :db-key1 b", "a :db-key2 c", "a :db-key3 <some value>"]. It is parsed as :where [ [a :db-key1 b] [a :db-key2 c] [a :db-key3 <some value>] ].
args is responsible for defining arguments to be replaced in where_clause, optional. Argument is a vector with strings containing the matches vec!["?n \"Ivan\" ?l \"Ivanov\"", "?n \"Petr\" ?l \"Petrov\""].
order_by is responsible for defining the order in which the response will be represented, optional. Argument is a vector with strings containing the element and how to order (:asc or :desc) vec!["time :desc", "device-id :asc"].
limit is responsible for defining the limit size of the response, optional. Argument is a usize.
offset is responsible for defining the offset of the response, optional. Argument is a usize.

Implementations§

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impl Query

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pub fn find(find: Vec<&str>) -> Result<Self, CruxError>

find is the function responsible for defining the :find key in the query. Input should be the elements to be queried by the where_clause. Ex: vec!["time", "device-id", "temperature", "humidity"]. Becomes: :find [time, device-id, temperature, humidity].

Error cases:

All elements should start with ?, example vec!["?p1", "?n", "?g"]. If theey do not start the CruxError::QueryFormatError containing All elements of find clause should start with '?', element '{}' doesn't conform is thrown.

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pub fn find_by_aggregates(find: Vec<Aggregate>) -> Result<Self, CruxError>

find_by_aggregates is the function responsible for defining the :find key in the query similar to find. However, it supports sending aggregates to :find keys. Input should be the elements to be queried by the where_clause. Ex: vec![(Sum("?heads"), Min("?heads"), Max("?heads"), Count("?heads"), CountDistinct("?heads")]. Becomes: :find [(sum ?heads) (min ?heads) (max ?heads) (count ?heads) (count-distinct ?heads)].

Error cases:

All elements should start with ?, example vec!["(min ?heads)"]. If theey do not start the CruxError::QueryFormatError containing All elements of find clause should start with '?', element '{}' doesn't conform is thrown.

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pub fn where_clause(self, where_: Vec<&str>) -> Result<Self, CruxError>

where_clause is the function responsible for defining the required :where key in the query. Input should be element1 :key element2, element2 may have a modifier like #inst. The order matters. Ex: vec!["c :condition/time time", "c :condition/device-id device-id", "c :condition/temperature temperature", "c :condition/humidity humidity"]. Becomes: :where [[c :condition/time time] [c :condition/device-id device-id] [c :condition/temperature temperature] [c :condition/humidity humidity]].

Error cases:

All elements present in find clause should be present in where clause. If your find clause is "?p", "?n", "?s", and your where clause is "?p1 :alpha ?n", "?p1 :beta true" an error Not all element of find, “?p”, “?n”, “?s”, are present in the where clause, ?s is missing is thrown.

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pub fn args(self, args: Vec<&str>) -> Result<Self, CruxError>

args is the function responsible for defining the optional :args key in the query. Input are elements you want to replace in the where_clause, a good practice is to name them with ? before. Ex: vec!["?n \"Ivan\" ?l \"Ivanov\"", "?n \"Petr\" ?l \"Petrov\""]. Becomes: :args [{?n "Ivan" ?l "Ivanov"} {?n "Petr" ?l "Petrov"}].

Error cases:

The first element of the argument key-value tuple should start with ?. An input vec!["n true"] will return an error All elements should start with '?'.
All arguments key should be present in the where clause. If the where clause ?p1 :name ?n", "?p1 :is-sql ?s", "?p1 :is-sql true" and an args clause vec!["?s true ?x 1243"] will return an error All elements should be present in where clause.

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pub fn order_by(self, order_by: Vec<&str>) -> Result<Self, CruxError>

order_by is the function responsible for defining the optional :order-by key in the query. Input is the elements to be ordered by, the first element is the first order, the second is the further orthers. Allowed keys are :Ascand :desc. Ex: vec!["time :desc", "device-id :asc"]. Becomes: :order-by [[time :desc] [device-id :asc]].

Error cases:

The second element of each order clause should be :asc or :desc, if different, like :eq in "?p1 :asc", "?n :desc", "?s :eq", error Order element should be ':asc' or ':desc' is thrown.
The first element of each order clause should be present in the find clause. If the order clause is "?p1 :asc", "?n :desc", "?g :asc" and the find clause is "?p1", "?n" the error All elements to be ordered should be present in find clause, ?g not present is thrown.

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pub fn limit(self, limit: usize) -> Self

limit is the function responsible for defining the optional :limit key in the query. Input is a usize with the query limit size. .limit(5usize) Becomes: :limit 5.

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pub fn offset(self, offset: usize) -> Self

offset is the function responsible for defining the optional :offset key in the query. Input is a usize with the query offset. .offset(5usize) Becomes: :offset 5.

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