struct PublicUser: Codable {
var name: String
var petName: String
var petType: String
var petToysQuantity: Int
}
try FQL()
.select(all: User.self)
.select(\Pet.name, as: "petName")
.select(\PetType.name, as: "petType")
.select(.count(\PetToy.id), as: "petToysQuantity")
.from(User.self)
.join(.left, Pet.self, where: \Pet.id == \User.idPet)
.join(.left, PetType.self, where: \PetType.id == \Pet.idType)
.join(.left, PetToy.self, where: \PetToy.idPet == \Pet.id)
.groupBy(\User.id, \Pet.id, \PetType.id, \PetToy.id)
.execute(on: conn)
.decode(PublicUser.self) // -> Future<[PublicUser]> ๐ฅ๐ฅ๐ฅ
It's a swift lib that gives ability to build complex raw SQL-queries in a more easy way using KeyPaths. I call it FQL ๐
Built for Vapor3 and depends on Fluent
package because it uses Model.reflectProperty(forKey:)
method to decode KeyPaths.
Edit your Package.swift
//add this repo to dependencies
.package(url: "https://github.com/MihaelIsaev/FluentQuery.git", from: "0.4.30")
//and don't forget about targets
//"FluentQuery"
I love to write raw SQL queries because it gives ability to flexibly use all the power of database engine.
And Vapor's Fleunt allows you to do raw queries, but the biggest problem of raw queries is its hard to maintain them.
I faced with that problem and I started developing this lib to write raw SQL queries in swift-way by using KeyPaths.
And let's take a look what we have :)
First of all you need to import the lib
import FluentQuery
Then create FQL
object, build your SQL query using methods described below and as first step just print it as a raw string
let query = FQL()
//some building
print("rawQuery: \(query)")
// SELECT * FROM "User" WHERE age > 18
let fql = FQL().select(all: User.self)
.from(User.self)
.where(\User.age > 18)
.execute(on: conn)
.decode(User.self)
// SELECT u.*, r.name as region FROM "User" as u WHERE u.age > 18 LEFT JOIN "UserRegion" as r ON u.idRegion = r.id
let fql = FQL().select(all: User.self)
.select(\UserRegion.name)
.from(User.self)
.where(\User.age > 18)
.join(.left, UserRegion.self, where: \User.idRegion == \UserRegion.id)
.execute(on: conn)
.decode(UserWithRegion.self)
// SELECT (SELECT to_jsonb(u)) as user, (SELECT to_jsonb(r)) as region FROM "User" as u WHERE u.age > 18 LEFT JOIN "UserRegion" as r ON u.idRegion = r.id
let fql = FQL().select(.row(User.self), as: "user")
.select(.row(UserRegion.self), as: "region")
.from(User.self)
.where(\User.age > 18)
.join(.left, UserRegion.self, where: \User.idRegion == \UserRegion.id)
.execute(on: conn)
.decode(UserWithRegion.self)
// in this case UserWithRegion struct will look like this
struct UserWithRegion: Codable {
var user: User
var region: UserRegion
}
Let's take a look how to use it with some example request
Imagine that you have a list of cars
So you have Car
fluent model
final class Car: Model {
var id: UUID?
var year: String
var color: String
var engineCapacity: Double
var idBrand: UUID
var idModel: UUID
var idBodyType: UUID
var idEngineType: UUID
var idGearboxType: UUID
}
and related models
final class Brand: Decodable {
var id: UUID?
var value: String
}
final class Model: Decodable {
var id: UUID?
var value: String
}
final class BodyType: Decodable {
var id: UUID?
var value: String
}
final class EngineType: Decodable {
var id: UUID?
var value: String
}
final class GearboxType: Decodable {
var id: UUID?
var value: String
}
ok, and you want to get every car as convenient codable model
struct PublicCar: Content {
var id: UUID
var year: String
var color: String
var engineCapacity: Double
var brand: Brand
var model: Model
var bodyType: BodyType
var engineType: EngineType
var gearboxType: GearboxType
}
Here's example request code for that situation
func getListOfCars(_ req: Request) throws -> Future<[PublicCar]> {
return req.requestPooledConnection(to: .psql).flatMap { conn -> EventLoopFuture<[PublicCar]> in
defer { try? req.releasePooledConnection(conn, to: .psql) }
return FQL()
.select(distinct: \Car.id)
.select(\Car.year, as: "year")
.select(\Car.color, as: "color")
.select(\Car.engineCapacity, as: "engineCapacity")
.select(.row(Brand.self), as: "brand")
.select(.row(Model.self), as: "model")
.select(.row(BodyType.self), as: "bodyType")
.select(.row(EngineType.self), as: "engineType")
.select(.row(GearboxType.self), as: "gearboxType")
.from(Car.self)
.join(.left, Brand.self, where: \Brand.id == \Car.idBrand)
.join(.left, Model.self, where: \Model.id == \Car.idModel)
.join(.left, BodyType.self, where: \BodyType.id == \Car.idBodyType)
.join(.left, EngineType.self, where: \EngineType.id == \Car.idEngineType)
.join(.left, GearboxType.self, where: \GearboxType.id == \Car.idGearboxType)
.groupBy(\Car.id, \Brand.id, \Model.id, \BodyType.id, \EngineType.id, \GearboxType.id)
.orderBy(.asc(\Brand.value), .asc(\Model.value))
.execute(on: conn)
.decode(PublicCar.self)
}
}
Hahah, that's cool right? ๐
As you can see we've build complex query to get all depended values and decoded postgres raw response to our codable model.
BTW, this is a raw SQL equivalent
SELECT
DISTINCT c.id,
c.year,
c.color,
c."engineCapacity",
(SELECT toJsonb(brand)) as "brand",
(SELECT toJsonb(model)) as "model",
(SELECT toJsonb(bt)) as "bodyType",
(SELECT toJsonb(et)) as "engineType",
(SELECT toJsonb(gt)) as "gearboxType"
FROM "Cars" as c
LEFT JOIN "Brands" as brand ON c."idBrand" = brand.id
LEFT JOIN "Models" as model ON c."idModel" = model.id
LEFT JOIN "BodyTypes" as bt ON c."idBodyType" = bt.id
LEFT JOIN "EngineTypes" as et ON c."idEngineType" = et.id
LEFT JOIN "GearboxTypes" as gt ON c."idGearboxType" = gt.id
GROUP BY c.id, brand.id, model.id, bt.id, et.id, gt.id
ORDER BY brand.value ASC, model.value ASC
If you will change your models in the future you'll have to remember where you used links to this model properties and rewrite them manually and if you forgot one you will get headache in production. But with KeyPaths you will be able to compile your project only while all links to the models properties are up to date. Even better, you will be able to use refactor
functionality of Xcode! ๐
With FQL
's query builder you can use if/else
wherever you need. And it's super convenient to compare with using if/else
while createing raw query string. ๐
It is faster than multiple consecutive requests
You can join on join on join on join on join on join ๐๐๐
With this lib you can do real complex queries! ๐ฅ And you still flexible cause you can use if/else statements while building and even create two separate queries with the same basement using let separateQuery = FQL(copy: originalQuery)
๐บ
The list of the methods which FQL
provide with
These methods will add fields which will be used between SELECT
and FROM
SELECT _here_some_fields_list_ FROM
So to add what you want to select call these methods one by one
Method | SQL equivalent |
---|---|
.select("*") | * |
.select(all: Car.self) | "Cars".* |
.select(all: someAlias) | "some_alias".* |
.select(\Car.id) | "Car".id |
.select(someAlias.k(.id)) | "some_alias".id |
.select(distinct: \Car.id) | DISTINCT "Car".id |
.select(distinct: someAlias.k(.id)) | DISTINCT "some_alias".id |
.select(.count(\Car.id), as: "count") | COUNT("Cars".id) as "count" |
.select(.sum(\Car.value), as: "sum") | SUM("Cars".value) as "sum" |
.select(.average(\Car.value), as: "average") | AVG("Cars".value) as "average" |
.select(.min(\Car.value), as: "min") | MIN("Cars".value) as "min" |
.select(.max(\Car.value), as: "max") | MAX("Cars".value) as "max" |
.select(.extract(.day, .timestamp, \Car.createdAt), as: "creationDay") | EXTRACT(DAY FROM "Cars".value) as "creationDay" |
.select(.extract(.day, .interval, "40 days 1 minute"), as: "creationDay") | EXTRACT(DAY FROM INTERVAL '40 days 1 minute') as "creationDay" |
.select(by: .rowNumber, over: FQOver , as: "rowNumber") |
rowNumber() OVER (partition BY EXPRESSION ORDER BY SOMETHING ) as "rowNumber" |
BTW, read about aliases and FQOver
below
If you need to use window functions like rowNumber, rank, dense_rank, etc. like this
rowNumber() OVER(partition BY "Record".title, "Record".tag ORDER BY "Record".priority ASC) as "rowNumber"
(refer to: https://www.postgresql.org/docs/current/static/functions-window.html)
then you could build it like this
let fqo = FQOver(.partition)
.by(\Record.title, \Record.tag)
.orderBy(.asc(\Record.priority))
and then use it in your query like this
let FQL()
.select(\Record.id)
.select(by: .rowNumber, over: fqo, as: "rowNumber")
.from(Record.self)
Method | SQL equivalent |
---|---|
.from("Table") | FROM "Table" |
.from(raw: "Table") | FROM Table |
.from(Car.self) | FROM "Cars" as "cars" |
.from(someAlias) | FROM "SomeAlias" as "someAlias" |
.join(FQJoinMode, Table, where: FQWhere)
enum FQJoinMode {
case left, right, inner, outer
}
As Table
you can put Car.self
or someAlias
About FQWhere
please read below
.where(FQWhere)
First is object oriented
FQWhere(predicate).and(predicate).or(predicate).and(FQWhere).or(FQWhere)
Second is predicate oriented
Example for AND statements
\User.email == "[email protected]" && \User.password == "qwerty" && \User.active == true
Example for OR statements
\User.email == "[email protected]" || \User.email == "[email protected]" || \User.email == "[email protected]"
Example for both AND and OR statements
\User.email == "[email protected]" && FQWhere(\User.role == .admin || \User.role == .staff)
What FQWhere() doing here? It groups OR statements into round brackets to achieve a AND (b OR c)
sql code.
It may be KeyPath operator KeyPath
or KeyPath operator Value
KeyPath
may be \Car.id
or someAlias.k(\.id)
Value
may be any value like int, string, uuid, array, or even something optional or nil
List of available operators you saw above in cheatsheet
Some examples
FQWhere(someAlias.k(\.deletedAt) == nil)
FQWhere(someAlias.k(\.id) == 12).and(\Car.color ~~ ["blue", "red", "white"])
FQWhere(\Car.year == "2018").and(\Brand.value !~ ["Chevrolet", "Toyota"])
FQWhere(\Car.year != "2005").and(someAlias.k(\.engineCapacity) > 1.6)
if you need to group predicates like
"Cars"."engineCapacity" > 1.6 AND ("Brands".value LIKE '%YO%' OR "Brands".value LIKE '%ET')
then do it like this
FQWhere(\Car.engineCapacity > 1.6).and(FQWhere(\Brand.value ~~ "YO").or(\Brand.value ~= "ET"))
Operator | SQL equivalent | Description |
---|---|---|
== | == / IS | Equals |
!= | != / IS NOT | Not equals |
> | > | Greater than |
< | < | Less than |
>= | >= | Greater or equal |
<= | <= | Less or equal |
~~ | IN () | In array |
!~ | NOT IN () | Not in array |
~= | LIKE '%str' | Case sensitive text search |
~~ | LIKE '%str%' | |
=~ | LIKE 'str%' | |
~% | ILIKE '%str' | Case insensitive text search |
%% | ILIKE '%str%' | |
%~ | ILIKE 'str%' | |
!~= | NOT LIKE '%str' | Case sensitive text search where text not like string |
!~~ | NOT LIKE '%str%' | |
!=~ | NOT LIKE 'str%' | |
!~% | NOT ILIKE '%str' | Case insensitive text search where text not like string |
!%% | NOT ILIKE '%str%' | |
!%~ | NOT ILIKE 'str%' | |
~~~ | @@ 'str' | Full text search |
.having(FQWhere)
About FQWhere
you already read above, but as having calls after data aggregation you may additionally filter your results using aggreagate functions such as SUM, COUNT, AVG, MIN, MAX
.having(FQWhere(.count(\Car.id) > 0))
//OR
.having(FQWhere(.count(someAlias.k(\.id)) > 0))
//and of course you an use .and().or().groupStart().groupEnd()
.groupBy(\Car.id, \Brand.id, \Model.id)
or
.groupBy(FQGroupBy(\Car.id).and(\Brand.id).and(\Model.id))
or
let groupBy = FQGroupBy(\Car.id)
groupBy.and(\Brand.id)
groupBy.and(\Model.id)
.groupBy(groupBy)
.orderBy(FQOrderBy(\Car.year, .asc).and(someAlias.k(\.name), .desc))
or
.orderBy(.asc(\Car.year), .desc(someAlias.k(\.name)))
Method | SQL equivalent |
---|---|
.offset(0) | OFFSET 0 |
Method | SQL equivalent |
---|---|
.limit(30) | LIMIT 30 |
You can build json
on jsonb
object by creating FQJSON
instance
Instance | SQL equivalent |
---|---|
FQJSON(.normal) | build_json_object() |
FQJSON(.binary) | build_jsonb_object() |
After creating instance you should fill it by calling .field(key, value)
method like
FQJSON(.binary).field("brand", \Brand.value).field("model", someAlias.k(\.value))
as you may see it accepts keyPaths and aliased keypaths
but also it accept function as value, here's the list of available functions
Function | SQL equivalent |
---|---|
row(Car.self) | SELECT row_to_json("Cars") |
row(someAlias) | SELECT row_to_json("some_alias") |
extractEpochFromTime(\Car.createdAt) | extract(epoch from "Cars"."createdAt") |
extractEpochFromTime(someAlias.k(.createdAt)) | extract(epoch from "some_alias"."createdAt") |
count(\Car.id) | COUNT("Cars".id) |
count(someAlias.k(.id)) | COUNT("some_alias".id) |
countWhere(\Car.id, FQWhere(\Car.year == "2012")) | COUNT("Cars".id) filter (where "Cars".year == '2012') |
countWhere(someAlias.k(.id), FQWhere(someAlias.k(.id) > 12)) | COUNT("some_alias".id) filter (where "some_alias".id > 12) |
FQAlias<OriginalClass>(aliasKey)
or OriginalClass.alias(aliasKey)
Also you can use static alias OriginalClass.alias
if you need only one its variation
And you can generate random alias OriginalClass.randomAlias
but keep in mind that every call to randomAlias
generates new alias as it's computed property
When you write complex query you may have several joins or subqueries to the same table and you need to use aliases for that like "Cars" as c
So with FQL you can create aliases like this
//"CarBrand" as b
let aliasBrand = CarBrand.alias("b")
//"CarModel" as m
let aliasModel = CarModel.alias("m")
//"EngineType" as e
let aliasEngineType = EngineType.alias("e")
and you can use KeyPaths of original tables referenced to these aliases like this
aliasBrand.k(\.id)
aliasBrand.k(\.value)
aliasModel.k(\.id)
aliasModel.k(\.value)
aliasEngineType.k(\.id)
aliasEngineType.k(\.value)
.execute(on: PostgreSQLConnection)
try FQL().select(all: User.self).execute(on: conn)
.decode(Decodable.Type, dateDecodingstrategy: JSONDecoder.DateDecodingStrategy?)
try FQL().select(all: User.self).execute(on: conn).decode(PublicUser.self)
By default date decoding strategy is yyyy-MM-dd'T'HH:mm:ss.SSS'Z'
which is compatible with postgres timestamp
But you can specify custom DateDecodingStrategy like this
try FQL().select(all: User.self).execute(on: conn).decode(PublicUser.self, dateDecodingStrategy: .secondsSince1970)
or like this
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
try FQL().select(all: User.self).execute(on: conn).decode(PublicUser.self, dateDecodingStrategy: .formatted(formatter))
or if you have two or more columns with different date format in the same model then you could create your own date formatter like described in issue #3
I hope that it'll be useful for someone.
Feedback is really appreciated!
And don't hesitate to asking me questions, I'm ready to help in Vapor's discord chat find me by @iMike nickname.