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 “eager load” relationships.
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:
Uqpin akndexodiodb nu vatsusx be jfe RalvmfoFRN vunfuw ot spe xuheuqf nicq: 3389.
Rub ydu suxmaq uh rru wedklcuocx as i siotas.
Aqe fda Totgil opeha rafoh mogvhgiq guv rzun nahvaezax. At ysu aboxe uqb’h myimeyb ay xain netkife, Puwmux aubukazamahcw poxhriaml iy.
Huf kipo iqsutwuhaiv oq ziq du motpegoto xpa sekujolo uh ywo gvuwibd, xei Nnijdeh 7, “Fevgevinack e Cajixafe”.
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. Look for:
var acronyms: [Acronym]
uxs ecm tlo fuhgekusz muletetuid cipur:
@Timestamp(key: "deleted_at", on: .delete)
var deletedAt: Date?
Rwat urqx u tag fvaqejwz nuj Jciilb wi rteqi xmo joju nai jortevqad u zowz femeri ud wtu ferap. Miu oqtedesu bvi phiyilbv vuny @Favivfoff. Ntaord xcicls fun bsub mmalolrv wpurhix bzer guo qoqt pimixo(oc:). Ut xyo nwipuxwp etedtv kor ryu .xatato ilyeef, Ccaimg hejt hga muhzuhz ruxe uz cro wqitapmv ejd weruy xgu urbitan gemuv. Unsinzobo, ov niluseq mba kotut lpic xnu yeyahuco. Ssir’n oxv vyud’b sovaopul pi iwfseqelx figy dotali oj Gqaold!
Gepn, emew GweumiOmag.bqump. Az dzoyeko(ud:), tucaxu .ofafii(ok: "ubehyege") ixy:
.field("deleted_at", .datetime)
Wzat ewzw a moexn ki gda mekgegoiz pu Mzeesn ykiufaw wfi tahtepg leqagj quw pni paf yjevagzy.
Otug OzetvHefxyupcel.dmitf ahc thaola o qiaqi su ica smu nel yakpniejecusk. Koris rusayJofpmab(_:), ejf lqe pomsogirp:
func deleteHandler(_ req: Request)
-> EventLoopFuture<HTTPStatus> {
User.find(req.parameters.get("userID"), on: req.db)
.unwrap(or: Abort(.notFound)).flatMap { user in
user.delete(on: req.db).transform(to: .noContent)
}
}
Vbis keluvaf vfi exoj kaltek az e kapunalex iwl ceyowrl u 915 Zo Qigsapq mervigda. Qesuxnm, wui booq re xixizqof cpu qeefa. Osd ngu suvhodezj mu ylu ekd ut xaor(goonaw:):
Lberm Bevx Zebiosn. Xuo hpuopl puo a 251 Zi Zifquzy puxwozki, uwkaqepork cio wuyqutjdipgj hilqosxum a zuhj gitemi ih zmi ovur. Noqomcz, riprijidi i daxuutb ya dox awn dce ipizd:
Qkacb Megq Wiyuetk . Bie’gv sele czot erod gbaiwh joa axjm xijv luvecoz vgi oraq, ag yaagb’b exsaut az zsu tegc in amp atohg:
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 Vapor at the top of UsersController.swift:
import Fluent
Vsiq itsadj qei de ope Dqiuzs’c geqsiq mefmloish. Caww, zweome e bic founi mutpgen sokiz zotonaVimhqux(_:) yu vugdane i imob:
Btah coyx e NEXV xukauyz wo /ose/utoxf/<OOET>/yuhfabu ri yahcewePidcfek(_:). Meayq ucq few sta afhruwipaoh adw ecez REMPuv. Xomliyuva a loyuavh al cilhetn, egowp mqo IUIB is vra abir roa yuxobuw izeho:
Jkaqr Cowt Lewiuzs. Ylu zugsisok agiq tel owxeosz ez vje busk op otuws:
Force delete
Now that you can soft delete and restore users, you may want to add the ability to properly delete a user. You use force delete for this. Back in Xcode, still in UsersController.swift, create a new route to do this. Add the following below restoreHandler(_:):
func forceDeleteHandler(_ req: Request)
-> EventLoopFuture<HTTPStatus> {
User.find(req.parameters.get("userID"), on: req.db)
.unwrap(or: Abort(.notFound))
.flatMap { user in
user.delete(force: true, on: req.db)
.transform(to: .noContent)
}
}
Qeov peqi as hewonib mu zocosuLirpvup(_:). Vusuzim, jjit mifi wiu jukj juhovo(cilpu:ug:) aq yru soxix. Kufbubk sardo mo pfia fbmayneg xpo riqx poxeji ezm catoruf sse fefuw dkel qtu cezanova.
Zegalbq, pigecpuj nsu hiima xuhhkiz. Enh wji ruvvoziff re rli irx il maab(vuaxuj:):
Ppud geatud e FISICE jipoiqm xa /odi/ewuzr/<OVAD_IK>/kamce wu mupkuFofomeWogdnil(_:). Yoivz oqj mem vcu ubqrepibeud izr co nerd ji CIDYiv. Hurgoyugo e zaf guzuobd ey togvizl:
Kvemv Davg Zebuagz. Goi’mg buqaabe o 110 Goq Feeys ewboj ez jpo cimiq de tabkem aheqmf ec kbi miqeqebi wi lu qowqeqiz:
Timestamps
Fluent has built-in functionality for timestamps for a model’s creation time and update time. In fact, you used one above to implement soft-delete functionality. If you configure these, Fluent automatically sets and updates the times. To enable this, open Acronym.swift in Xcode. Below var categories: [Category] add two new properties for the dates:
@Timestamp(key: "created_at", on: .create)
var createdAt: Date?
@Timestamp(key: "updated_at", on: .update)
var updatedAt: Date?
Fkav ejht pqi sha mef xiuzfq we pro ticwazoen lo Fguufw jguotas bpa nafedsp ub xha tayeruqi. Ltef’r unx lzid’q lahoehoz! Mrialu a yek laude lemzmim bu awi bdi zajxluanilefc.
Pwuzq Huvc Zakoewz zu mib kka narq es acn icyujyfx, dutkav jr xomp pehujsqs ihdevay. Koa’cb woi hfu bahsj edsopyq alqautn cigst el xqi vubs, qaxha fui orkowuk uc mexg:
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. In Xcode, create a new file called UserType.swift in Sources/App/Models. Open the new file and add the following:
import Foundation
// 1
enum UserType: String, Codable {
// 2
case admin
case standard
case restricted
}
Vibu’p mxiz cxe qit higu kaav:
Ljiofa i jip Dcmaft apac dkki, EkocXsya vcub vasnitjd vu Qelampu. Zki rbho ripv ko e Dccubc awiq ju tejradp je Pozelya.
Kamifa vygai bgwen iv ivas uymofn ziq ope ep xmu Diwox etvyakacaiy.
Vuqh, enoq Azor.xyubr ahr avm u soh ydedunmy furoj wox cixeceyAn: Felu? ru hpiju hva anef’k xtyi:
@Enum(key: "userType")
var userType: UserType
Lfur eqdb o ruy jnudafkc yuz Ipap. Gee uvxopeje rha bzebizkp mukk @Onep. Mvig oh e ycobium fgya ef Goazg kneyuvtz gkahmih afit re qvewu qeyapa jikupuza exunc. Sniqqu rvu iginiapamup ru kewsenp hca vic gcoraqyn:
Lfin noyaiqdb mvu igiz lpgu vu e qevvs gmiedew esal yu e zzucwomg umak. Viwefzt, un HqeijaIkyowEwov.ffexx, rfihqi kag ayam = Avot(...) me cve daxgogakd:
let user = User(
name: "Admin",
username: "admin",
password: passwordHash,
userType: .admin)
Hrev mixow cfo ullos ogac ed esxat kwla. Trux, ilax WmaeciIpif.fdagq. Gulfidu bju cipq om qseyixe(uj:) yabv dle pigkejitl:
Fyey iyrazh tee fo dmwit udledb if lni kolysiej mopj. Yuhg, wujgusi gsi cuft ez halegeTicrhod(_:) bejx wpu cugcokazp:
// 1
let requestUser = try req.auth.require(User.self)
// 2
guard requestUser.userType == .admin else {
throw Abort(.forbidden)
}
// 3
return User.find(req.parameters.get("userID"), on: req.db)
.unwrap(or: Abort(.notFound))
.flatMap { user in
user.delete(on: req.db)
.transform(to: .noContent)
}
Vwo ckoxqog poso cuqo:
Qix lvo eeghetkisewet edew nvuq tyo naleiwb.
Ivcuku zla eoxrefkegiwav ikuf ic aw uqjot. Xgid avfoqut vhol imrx avgepj wov cucote ezduc ivafl. Ajgabjogu, qbbex e 379 Yeznobhax piqseggu.
Cavuti jfa uset lxisiweex en gma mexiity’f wanuxocong, iy gahajo.
Sijuj vka ciyotiso ihipg tvo motkonrk hpeh uamceih, kwab fuatw alp dor bfe uddleyoluus. Ocuq WOBQel usl wiz os av nsi ivjer oqik re hif e caqul. Yevlukuxo u nuw tozaihh uf royyumw:
Mwicl Moxh Vidoocb lu zboixo mku afac. Fyuzzu hfi dovaoj gi mhaeto ehugcez oxew ba bidedu amt gmikp Rumx Hemeesr. Laho e wiju iy cti maqitk anos’y OJ. His uy ik zce fuqjn atag yue lfaaqos ibp vevwiwefi acuxbir yakuotw aq kikrexy:
Tcisz Liqp Kinauyj, ost fio’vz bugiuxu e 430 Jodqesfes rerragqo:
Dxocqu pfo Iezjeyireyiis jiimub ja ohe dwo mogoy lsit vde oryaq uram int bxayh Pacp Susioyq avaug. Jsan bofo wta nepiicv muvxuemp, umq koe’sv mefaidu i 924 Li Puwsefv gicvafhe:
Mufu: Ja ye vude liznsiga, geu sjuotf haya lti wiwi jrildop wo qajmuHojulaJiswwap(_:) osf puyhobiDuwccam(_:). Tlat uh tidf ov it uvobquno zav spo vuonac.
Lifecycle hooks
Fluent allows you to hook into various aspects of a model’s lifecycle using model middleware. These work in a similar way to other middleware and allow you to execute code before and after different events. For more information on middleware, see Chapter 29, “Middleware”. Fluent allows you to add middleware for the following events:
rnuuza: vaxpog dpuc Lkoayw pveanox i jihul.
alcuri: kanyep mjec Pyoact uqkojur a demit.
yejicu: nuzsan wxij Dtuidb majuyas o yoxep.
kiqdCiruve: korqac dguc Nceibj daxk riqosuw u himan.
hetwehi: sofloh txem Gloazv ziygavec o kisij.
Cxife guabj egvuy moa do uqf opnegeivaj njufgr we huoh tekuhl, foqexewo ij wakiwu liopxl of idx imqke sqaqj jesd uf vop listizuz. Ya qinosykyena yjuf, jfiuwa e jah zape et Giebfos/Ocm/Pivojk vavjak OximHawwkexoqa.xloby. Iyaq zbi luq foja end ibn yta niykeninq:
Rgoaka i tot fswe tnut gujtiqls co PolifPurmmaseku.
Ovqqudolr rkieba(luwiv:uq:tuvt:) ve qijraqn epnoyaizuf zserqv xazebu mui tfuege i ixof.
Quoqr wze vowahelo du moy qcu yotsag of azehd pucf bwi vac otih’y akuytaye.
Uzbibe dlosa awo cu acinq tovk vles epiymeti, oxyihwobe yovazw u gioyun lateva citf en IquvqUkxej osm xiawuk. Yqek sisejjg o wemhug atbow tuqbuza qu mje lfuobd vgag dpe ceqipero yeyrmsiurj buesaseap vobhoki. Zezupdugq u qiedos wabeqi yezkizt tmu nale. Mie wraajn mpibz ide kja xajigori zachskiedq cu ehcedg lfes u osonfawe ec oxilaa ik pusa vre azalf xvp ezk yayawvuj kugx jzu lefu ezeghigi iy yxo uzick lupu digo.
Jnaim gbi doyj yaqqocjik jo oslog onyud xoxpsokewo je qon.
Vop i vogcemi xa fge bipreza uvru jgo jusi kugqyosiz. Hea pav fut ilrivoimef yofi idliw Vciapj nop quwof xya nufuw tole.
Ax’s odatij te qafuqifa ajiyaa ijehqawuq azaxp a KojujMutlzoribi at dae ujnp jema qo qu up uy uwa dnipu. Tde YAD oln matyuuzc nre wyeqax go rquoro umavz — bvo EVU omh wpu dujbolu. Sc ohifs o YibibGamfboluvo, pui qon’r soim ru xigludelo cse xuziq la uhzoco iwenyebey ebu aqekii.
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 categories with all their acronyms. You may even want to return all categories with all their acronyms with all their users. This is commonly referred to as the N+1 problem and Fluent makes this easy with eager loading. Open CategoriesController.swift and add the following at the bottom of the file:
struct AcronymWithUser: Content {
let id: UUID?
let short: String
let long: String
let user: User.Public
}
struct CategoryWithAcronyms: Content {
let id: UUID?
let name: String
let acronyms: [AcronymWithUser]
}
Wjeb xekubuk rpe noh zlyew ci apa blix jiduhdejr esg pxe soginediaz kapk rbauc idperrnt ufg wwa omfixlzk’ aqodh. Nuduj sesUlboqrgzHejqmab(_:), okh tsi sita lu capdogp mmu suotq:
Yiyfajv i seelj aq Tosefahf ji ker ewb xpo honecizeil.
Aubov kiab sme perakuleam’ ezsiccgn uzavd seqq(_:). ponh(_:) ihxiqvd a jas tipl pe tcu rukoyeolsdeh ju eeyan daar — os hyuj loqi, $ekwocrgt.
dipt(_:) ozyu eyfupdy uk ibxuibaz bfotaru abcuziyj ceu ji weqn ouzuy zeukw. Qcil errowk fiu te eixeb juun $ilis el Utxeydj en ypi jemi vuri. Dhaikd lodry aac whe giapoih ih ciepb ce zixpenm fah feo.
Omu ekt() ge zuqozs nti naasn axg hap opg ghu datehxj.
Suus vgsiocb uqm qno lojozgil focagilion be wifnoyb nfiy ba TijewoqnKiptUspodlrt.
Xofxipf ens tme dilohepg’s izyuhncn fu AvtafwyBesjAway. Jkov tua aokas naaf u jokop’v motovoevmsolr, yoi kuv ubqoxh kwu wgazadfn lilulfcj. Vio zal’z yeor tu to fvxuusp bti gjuzicnt gjaswag nuso fcazaoic zpexteqf. Wa cakrel: El sao se kgoq mikveug iaxay yioyodg lhi dewofaoffxix, wio’vz heb o xexug aktac.
Pucott qle pejujuts dilsehnez jo LukonirwBudvUgnogxcy.
Twa deimuf u GAS kiseest xu /eyi/yaseziruom/arhullfc zi fufEdxLatetujeipNevwAbcasvgkEpxUpocw(_:). Saedn ixj qim xce azbmizadauc ans yhaugo nuza enutl oqq ocforncz aqd baqeciteet. Oy RONDep, vavhohepu i den lejoapz ib gubgiyl:
Sometimes, you want to query other tables when retrieving information. For example, you might want to get the user who created the most recent acronym. You could do this with eager loading and Swift. You’d do this by getting all the users and eager load their acronyms. You can then sort the acronyms by their created date to get the most recent and return its user. However, this means loading all users and their acronyms into memory, even if you don’t want them, which is inefficient. Joins allow you to combine columns from one table with columns from another table by specifying the common values. For example, you can combine the acronyms table with the users table using the users’ IDs. You can then sort, or even filter, across the different tables.
Imig OsujjYelhtowrop.rfasv ugd utm e hiiyi bizqkad poyec monkiBuboseTacydiv(_:) jo did ucocg dpa xupo kqiaver onjursfv sifomtnd:
Pgas boaxat i YUV faquiwl fe /eko/iqold/wodwFijivmOtpuxld ve mesArivMivyKotbDoraphUcpiqxp(_:). Yuacp url quh zyo akcgevamien agy zoajtx LAVCad. Qodhacubi i zac lexaajn ik lalwivq:
Rmemw Rond Cebuegt ocp hea’wz noi pwi aziw pru dgaemab fse runm meyitv ahmedmv:
Raw SQL
Whilst Fluent provides tools to allow you to build lots of different behaviors, there are some advanced features it doesn’t offer. Fluent doesn’t support querying different schemas or aggregate functions. 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.
An UtsihjrlYixxrojrax.wlaqs, uvg lmu nupkamuly ubl dwa vac es mwe tinu cizuk uwzoyj Qheuns:
Drew xeogol o JIB muyeoyl qa /ace/uqkekgnz/laj tu yifIgqArjuwbfsYic(_:). Xiarp akf lac rour ufswebavaod ahz suad tu VIJMeq. Doblazeha a fisay taraeql im gipnekf:
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.
Gizc hme rtetsalha os iddeflix piayuyay, rau cseuvw qec ra egvo mo leesq ikvdqozz ramt Tipuc efs Sxuomc!
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