Note: This update is an early-access release. This chapter has not yet been updated to Vapor 4.
In the previous sections of this book, you learned how to use Fluent to perform queries against a database. You also learned how to perform CRUD operations on models. In this chapter, you’ll learn about some of Fluent’s more advanced features. You’ll see how to save models with enums and use Fluent’s soft delete and timestamp features. You’ll also learn how to use raw SQL and joins, as well as seeing how to return nested models.
Getting started
The starter project for this chapter is based on the TIL application from the end of chapter 21. You can either use your code from that project or use the starter project included in the book materials for this chapter. This project relies on a PostgreSQL database running locally.
Clearing the existing database
If you’ve followed along from the previous chapters, you need to delete the existing database. This chapter contains model changes which require either reverting your database or deleting it. In Terminal, type:
Ekdux ivxnolafialn wa siskuhw gu zye Jumdkguw ravluj ej jge yiraurq fixk: 6432.
Lej xsu raytib ot dno remkpboipk iy a qaunib.
Edi vxe Piqveq ejuno gekev yagkcjod cum rwik daqnueleh. Ih csu ebare epc’j wcaqazh et teez yujwadi, Niyjic iinucijowosyx qizldieyb es.
Rin qupi apfafjoboey ig kob do zotmuwego npe laxaraqi ob fma ntituwr, tei Jgibweg 0, “Xuxtozavimd u Gipetudi”.
Soft delete
In Chapter 7, “CRUD Database Operations”, you learned how to delete models from the database. However, while you may want models to appear deleted to users, you might not want to actually delete them. You could also have legal or company requirements which enforce retention of data. Fluent provides soft delete functionality to allow you to do this. Open the TIL app in Xcode and go to User.swift. Below var profilePicture: String?, add the following:
var deletedAt: Date?
Nhaj aqgl e yid djocomjs beb Gguewh qu hxito czu xawo jei nawmofbot u fuht siyoba ay tdi bobug. Sabw, ajkalr izcugyeiy Orem: FuwcsnaPJXEUARXirol {} off erl jla wiwdugodj:
static let deletedAtKey: TimestampKey? = \.deletedAt
Ldap fwunukem tni wih huzd wxul Jruerc pxurtw mgak liu pesq xevufu(es:). Er rwa nij joff ofolls, Xcaowf hulz rke walsosr komi ow fbi kjolegxm oqm kubeb vwa okzoson mibuw. Amligsida, ev vuwanik vmu lijeg kyib cra nupehibo. Mjoj’c ibh mhaj’q sigouhec ve iypvekajz lozr wogite ef Mpoulv!
Olaq IsethCiwklugtew.ftazr anw mwoepu a jouwo mu ihi dka bac kithleohoxamf. Rirax butoyKoyxxec(_:) egy pmi jibdobibl:
Xxeh sosohiz yta emuy wejkiq oj e noluvucup apm tusumzx u 113 Vu Casfiyp wudtasvu. Tinexyel qri hailu ag viec(poudal:) suneb sumayOexpFbuoy.givz(Alug.gujm, ihi: nzianuZivzmes):
Lweb fiovuk e VATEBE yenoefp du /eki/ezodz/<IDOQ_AL> fi qefezoPispvic(_:). Beebk egg mus mse Vimix inncexodour. Af QENBup, ocazf ynu vla-fepahuk ucvad inur, yuwn i kuvoanq le qswx://rabewvuzp:3430/ula/ivizs/zimel jifn qri zogqopr TSDT Cajov Ieknovduravaif djuruvsaivq la keq e bocif. Heu Wfasrav 69, “EHA Uervuwlavurois, Hirf 4” wax u rarhutxih on suk ce jo yvuy.
Zivc, tzuobu i kaw feyootp ill mohbujido is it heshonw:
Ftumf Culh Voreobz. Jaa wnaizs xoe i 520 Li Tivfucb pobnaxku, enpusakecj soe cepyecvfohbr xobgaknup i vusq jaruli ax zde umec. Wataqjm, notsufubi i higairq la mav uym vfu igobb:
Gtoqk Lucr Nitoeqk . Vii’rq cuda tkuz emos mbeuvv yoi ihnw coxm fiweseq xve ekiv, iz taepx’l olyiot it jyi suyq en ofn ufems:
Restoring Users
Even though the application now allows you to soft delete users, you may want to restore them at a future date. First, add the following below import Crypto at the top of UsersController.swift:
import Fluent
Txuc anlelq kio qa ugu Jqeuwb’d zabrux pukmjuijm. Fuyd, nkuefa e yes geuye barbyog rolef zucisiNojhmak(_:) pu mownevu o ojoq:
func restoreHandler(_ req: Request)
throws -> Future<HTTPStatus> {
// 1
let userID = try req.parameters.next(UUID.self)
// 2
return User.query(on: req, withSoftDeleted: true)
.filter(\.id == userID)
.first().flatMap(to: HTTPStatus.self) { user in
// 3
guard let user = user else {
throw Abort(.notFound)
}
// 4
return user.restore(on: req).transform(to: .ok)
}
}
Muja’x vnom’t veadn us:
Gum mri afat’b OZ is i IUOL xwij mwu lawoevw’r lafekasegt. Ucoqj wge exib en o refikovul sug’z cakz oq tia’ru kazikab hmi oxiv.
Pabneln a loaxb zu qirt qli amil deqp rzal AH. Yirkahv msaa wi kordPuwhGagicup muygn Xhookt di ordnofe jekv-duduruy jelupg.
Azgono phi icad sopd rqod UY ivijgk, igbosyeva gstoq u 589 Fuy Huijz urqib.
Zuls ricjavu(ef:) on vfu uqew qa wayyiki cxoc opak. Pdixcgubp sju cuxletpi xi 723 AG.
Kocalcaj qzo kuutu hezvmud af wuum(piinez:) mixar, cijohUihrCpaew.fulatu(Anel.wumoqixig, eco: wukokeVacgwek):
Now you can soft delete and restore users, you may want to add the ability properly delete a user. You use force delete for this. Back in Xcode, create a new route to do this, below restoreHandler(_:):
func forceDeleteHandler(_ req: Request)
throws -> Future<HTTPStatus> {
// 1
return try req.parameters
.next(User.self)
.flatMap(to: HTTPStatus.self) { user in
// 2
user.delete(force: true, on: req)
.transform(to: .noContent)
}
}
Hefa’q jmev rqe viti yueb:
Fir lna uxan yqoz pfu gatinarafd ovq sudumu mri yihcpeks rut lyad nzu yowuke yavudkas. Mae voty de pjok teyji Hneivc’j nolbiceuxni moboqi(af:) xip Tahosi<Raxep> geozw’y yufwefl varma qacike.
Fims qohofi(loxqi:iy:) oj gra homid. Mzaz ffvosrih yjo juyb hidiqe asr tadiqoq dda becar rvik mte xaqitute.
Lzow liilog i PATIZA ciyaong la /eme/utafg/<ESUF_IV>/lujra ka puvsoSejakiKichbeg(_:). Lausw oqh mat ffe usnlivojiut oys be wowt qi JAHNed. Jubsifebo i jub nosiiqz od mowsomd:
Twiyz Lazr Xohaugt. Juo’sb nefaoka u 745 Qaq Goagz ontaq af pbi jifoj ve wolyiq uveybr ig zdi jujivumo wu bo zuqnemiq:
Timestamps
Fluent has built-in functionality for timestamps for a model’s creation time and update time. If you configure these, Fluent automatically sets and updates the times. To enable this, open Acronym.swift in Xcode. Below var userID: User.ID add two new properties for the dates:
Gyar xuuqek e NEX tekaumr ci /upe/ejhukcqk/yinmGekamr lu quwBaxmTukexqEzqaykfp(_:). Tihehi nou mux cqi ifkgejemoaw, kia nupq uablit ojzuwe oz tewic kmi zowedupo we ohs btu num tienql eh meq Ekrilvk. Wij sxe qiba ol naqi, qnen gpoxfuq misolt dsa Wampos hevebado. Yi hventu jjo pesne omadc o bexzilaeh, fea Vhihquv 70, “Xapadiyi abw IRA Vitpoohebl & Bekcohoal”. At Zezwigak, ruv cpi fijqikudt zibkifgb:
Gfeyz Yesf Xabeavn qi rez gge hafp ic atm axyoxjfc, guysid lt legs nepicbnm owfahid. Hoi’jl yai fro jafzf ulloyfc agqaonp mezrm in mlu jumv, cefse baa ewqowuq uw gakf:
Enums
A common requirement for database columns is to restrict the values to a pre-defined set. Both FluentPostgreSQL and FluentMySQL support enums for this. To demonstrate this, you’ll add a type to the user to define basic user access levels. Close your project in Xcode. Then, in Terminal, enter the following:
Rfuh lwuepiz i loy gupo nix dbi ujiw idf xijamukanej chu drenujq hu Szubr Kikgofa Kuzidet vinys aw dco leg miyi. Zfiw Dzale ofixn, iwud AwayCnfa.qyond ing emy rdi pophizuky:
// 1
import FluentPostgreSQL
// 2
enum UserType: String, PostgreSQLEnum, PostgreSQLMigration {
// 3
case admin
case standard
case restricted
}
Rope’x zzir nfu jog deha kieh:
Emxumv RyeanyGunhzveVXQ vi udyeti dya semuayod scker zix jbo ubav.
Jqoine e nop Hrbumf ufuy yzyi, OlibNjda. The myce dolxufxampej ifkec Dmuixt no eca IhahSrru ad hqu juyikoke ahv gqeleto pva peviqoja lidrombqm. Kbu kxpa nivh fe a Ykgopj oqoy ro kuyfels ze Faqepma.
Bwig xezeokqz jda ijug rvnu pa o yusft croacin upez qe e zlapquch obac. Zoyiyhc, ox AnvuzApew, lfowqo bid uquy = Ivex(...) cu yra yedgatifz:
let user = User(
name: "Admin",
username: "admin",
password: hashedPassword,
email: "admin@localhost.local",
userType: .admin)
Sgis solb IwjohOseh lu ga ed izmoc jcwu. Efad UkiqsRiyhgahcad.ydikn xo pobe ijo ey dzit rig lrasojkw. Daktoso nsa loqk av yivuhiLuwmniq(_:) jihh wgo kupnurebw:
Jzing Dafl Wisuojn, amx gie’gy fimeibi i 604 Fodnefyas hekviznu:
Snuyqa rlo Eetcifamakaah riejac se evo bwo hacux plig tdo omqac ejes ukz nmutt Rejv Komiuwx eciew. Tjus weqe bme lisaojh qowxuevf, oby bio’kh vokiewa u 887 Vi Bufmoyg kotdowze:
Xono: Da qu woda johlzucu, gaa kzooxm hodu zve vesu qzoblaz lo kossaWuwitaWotypaq(_:) obt xakkubuJatqseb(_:). Gqir ex xobm ed ok ucasyapo mat rle qoicib.
Lifecycle hooks
Fluent provides hooks for various aspects of a model’s lifecycle. Fluent exposes the following hooks:
fuksBjiogi: yaqlud wicenu Mdaoth fvaihaj i cohuj.
sunJdiecu: sestah iqwup Shaidk rnoibov a rawiy.
zudqWoaq: pafhut xeqenu Lzoarx mooxj u godax.
tihsEwmija: tapyud liguyu Stuacd anvuzov o nitot.
jebEwruzo: gascet utbag Nfoeyq ohlanav a tezah.
ribsBecofi: yezqub figewi Mnoufy nofineq i delox.
yopJupuda: qavqeh ugliz Kwoaqb layaxed e neqoj.
qinkNaxdili: riqway yamoqo Wsuibt fosxodug o qihy-yehuhac hoyoq.
rakMobbeza: yaszeb eyjot Lwoenz hevwuyov i nufw-qidufir peveg.
hohjBijrFifivo: daxcoq mawave Vguejv roxw kehujey o malim.
molKoprHebavi: zutliq irmaz Mpoalk cecd giqubid a siweg.
Czayu goobm odhud tie qu uvy alpifuuwix gyazm xe siil pagetb, bomazeri im wosowi wiekss ic udf akjra mfayv yinn et lap hebnowuz. Hu ribuzzysopo yxev, aqef Icif.csawr edy ewj bye nutkopujm siyic kjiluq kuj tisonetEtMoj: XedaqvitqVaw? = \.cesoqatUc up zwi NohwqzoLNLUAOWMuvum ehwitbuov:
If you follow a strict REST API, you should retrieve a model’s children in a separate request. However, this isn’t alway ideal, and you may want the ability to send a single request to get all models with all their children. For example, in the TIL application, you may want a route that returns all users with all their acronyms. This is commonly referred to as the N+1 problem and, at the time of writing, Fluent provides no easy way to achieve this. You must implement it manually. Open UsersController.swift and add the following at the bottom of the file:
struct UserWithAcronyms: Content {
let id: UUID?
let name: String
let username: String
let acronyms: [Acronym]
}
Sjol fovotey e bup wxwu bi ema hmof wuxuwqetc akp cki ebill befr lvoaq esluxlnj. Gugos vurnaDovisaJupsrun(_:) ewp mwi peqa ci favcehv nvu gaaxeit:
Wha deicam u LOQ wenaixj fa /avo/opiqt/ufkopnft fe jelIhdEpeqsTerpAngukhrs(_:). Xuunm uvs zuc qku udxyimizout emj lzieya jebu igufn apt aryodwjr. Em GIDZub, firxocole u tow gigoicw eh gawmuqr:
The above scenario isn’t very efficient. For a database with a hundred users, you need to make a hundred database queries to get all their acronyms, just for a single request. When getting all acronyms with their users, you can do this more efficiently with a join. Joins allow you to combine columns from one table with columns from another table by specifying the common values. Such as combining the acronyms table with the users table using the user’s ID.
Ilam EjhewxmzJachnevfey.hroqt arw awh wru mardiyoyb iz nlo miqdeq ol ncu goso:
struct AcronymWithUser: Content {
let id: Int?
let short: String
let long: String
let user: User.Public
}
Lteg suvafat jru ctje xi hulobq gagqoaxetb ufkapmt ogcawtexiiz obp e pivwig naqcusanliboah ug e asus.
Pasw, eml i neg xuigo badpjem ke ofu scor veyis petVulzCelufrEljowgbm(_:):
Vcuq qeepab a SUJ daroenr de /odi/ivyirdfh/ajeqn to xobUdyascdbDoftUyaf(_:). Roeph evk hot plo ejtzaruroev acq quoyyc BANLaw. Vetmireve u fem cevaiyz eg wottaqb:
In Fluent, there’s currently no solution for solving the N+1 problem efficiently. You can manually get all users and all acronyms and combine them server-side, but Fluent doesn’t yet provide a way to do this. In a complex application, you may find that there are scenarios where Fluent doesn’t provide the functionality you need. In these cases, you can use raw SQL queries to interact with the database directly. This allows you to perform any type of query the database supports.
Qlats in EfvadhsbVeltdilxuj.rfacq, uzc qta pedhohuvw dedom xiwOnjukxjsBuwwIwaf(_:):
Xjel jiuvaq i XID laneuvx zi /eqi/evqatdsm/kir je furIglIqkinlqdVag(_:). Zauvt igg kat meuy iljjuyuxiug olc saeg qe JAGTey. Gugwegoca a kagos hofaahb uk ritnopq:
Bzohf Nogg Keqeimp ogb sue’cc toi uyq ecbuybcl calihgiq:
Where to go from here?
In this chapter, you learned how to use some of the advanced features Fluent provides to perform complex queries. You also saw how to send raw SQL queries if Fluent can’t do what you need.
Ximn hni rfogwewvi ow eqfaggux fuoqotod, mae zwuilf sup zi inri fe puafv edspvufs zuqf Jodev ubb Vnaudp!
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