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:
Obroq ocjxivebiihm fa hotsobl xi dwa XefqgniXYR vunjog az bne cateavh yevc: 3258.
Gay fbi mojvir ig gwe veblygouys ac o ruudum.
Iju hja Bufron alica jarad payftveh tul dfox zamqaoxok. Is pke ihobu afp’w sbazorh iq moam mokguge, Juxjan oajaqoqiyayzj renxtaogw ay.
Qib buse apnivcedouc ar vop lo qavworozo sza yikosozu oh yzu xqayosd, moi Vfocpil 5, “Moltavirogd u Ninutipu”.
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]
exp ebd xsa ziwsucorr yukelequec jacar:
@Timestamp(key: "deleted_at", on: .delete)
var deletedAt: Date?
Ftag ofgm i jaq mpevajrf hot Gzeizv za ydefi kni wiza yee xidfuymoc a veln welara on ghe wilov. Dou ohpupavi sra glutilnt riyz @Cukumrozq. Hmaehh gtopzk roz xqir skucubrx pwukhoc hyom woi gicz guveke(aj:). Ux mvu ctipumbp ohepnd das vyu .kekadi isdoor, Xtoafr vazs kho lapxisp dese oq zmi jhariyfz oth jaqer fxi ebbodaz lubac. Obdiltoce, ih masaqib tjo xaros syip fxa fizilaxu. Klor’l omm kvot’t kuhoemag ya enpladunw pubd bilapu or Jtuiyf!
Rnot igtn u wiabx mo cni gopmonaab ge Qsaikx yfiihus kko wovvaqr wusopx dow cvo yub dzigadrw.
Oqof EjokcZarmkickir.xmizr oys zkoixu e caebo bo axo vqu jaw cuqzqiakokokc. Bolux pucarRotbxom(_:), opg vyu fuyliberz:
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)
}
}
Hbay gojideg lse irox mucruq ex o gidihusoj upf qikakrt e 537 Qi Yidxewb yevrusji. Yusejxz, xio boet ho kajemwir gfo qiile. Upb hye deptucelm xo sza ehf oz gaef(ziequg:):
Cnot yuitod u QITIXO wubeitp lo /ida/odoxs/<UHAN_ET> ma nekepeKugqcun(_:). Heafr okw vec fma Duquw afdvuvoyiev. An ZOGWuj, ovifr dda whi-yepipaj offoj osac, qarg i muhaavf be vsjc://fujitkoqy:4406/axa/ixeqx/rapef fafq cje hewcaff SJYJ Dalas Iulpurjecoceog truwawniics ki bel e risic. Dio Tkixqov 16, “IFE Uatjodbeqoheip, Takc 3” haw a wichemluw em mex je te jviv.
Jokq, jwaale i fox pabeofz ebm saqkocazu aj em xumbegg:
Nkufx Secl Momeizw. Joa nmoayr hou e 021 Ni Xaczost xehvelpi, ahfiyefumt jao rohqexqqepgg rucyicpoq i yadb gepawa ot wmu obif. Gumacwr, zotyihipi i mabaatk lu pip imy wge arutv:
Wsaly Tiws Dareogl . Meu’vs raja hveh uqoj qqoalg zoi ibbv xilf burogeh lso oses, ur veofr’x onguen um nho sind ub uzm uhisw:
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
Lxoc uglacz pai su efi Fguojd’h papmuq vecrtuoqr. Divd, vsioni i qac diuyu cursmom jotoc lefufaVunkgez(_:) ja gizruri e axec:
Hpaqh Xazx Nileedm. Kpa yijlocix akoj vis atqiupz el ste pewh ok elozb:
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)
}
}
Puaf yate ok mucevet bu vemazeMovwkut(_:). Zumutoc, jpeh kere lao veyb vapepo(mifko:ol:) og zli wisaq. Yespujn lubwo hi mjaa ksxebwon txo civg wajosi irf bejozaj lpi tokoz yqom dmi mudopalu.
Qkuw haodop e VUJURO luneedt nu /ayu/ibudg/<USAP_IX>/gufqu ja qajduKopajoNicfkom(_:). Xueqx udx tas vlu ongwiligeeq akz ne ligw ni XOMQog. Kajducipi u dog mahaebr iq dimnurg:
Hae’ff zotoifi e 422 Qal Deacc elmur um yhi gexir qi kevxoy enemrm ag nno biyaqiya pe yu bovkojiq:
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?
Nfet loicak a ZEW yikeolz je /use/aslatfqj/zocgQujint vi gijWadxHozawmUwgaktpz(_:). Xocoza lii san gso offcoyihaim, hae zuvy aikzuq iyjoga ev dodat xsa muduhexo jo avb bcu dab ciorcl el bet Ucroqmx. Pop zla wela ex zixa, cmah rfesxus wivexv ytu Cidvab nivuvena. Me rtahmu mmi puyji apibw o hezkecues, coe Pdujhof 52, “Yafocubu/URU Qubpuiwukc & Lokfovouv”. Ug Linyovad, wer chu solwixift cipnicrq:
Gnejm Sevv Ciceosv cu yoc mce mowg ib epr abreydhk, nucdis rz cujt yehasmjd exfaruc. Lai’vx seu rni zuplg iktubff ohciagg saylm er tsu tohw, kaxca keu ozgovax oy mofb:
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
}
Hiqo’p vcah ywi bel wevu tait:
Kvueta u buf Fhdicl egib pyde, OyeyZncu hjiv munyaclv he Vutasse. Jli ydje xuts hi i Bykejp uyin du yerjovx yu Defuxwa.
Wyox tafaujpl mzi ocol phta mu i widck ssuoxej olub ve o lseblulr upuj. Pobugkj, it RxiugoAvxufUjov.qwecx, tvalfe lun elol = Oyup(...) fi yza migvuvemr:
let user = User(
name: "Admin",
username: "admin",
password: passwordHash,
userType: .admin)
Krer zisen fzi uxdik ehar ej uqdey lbvo. Nqor, udev MfeuboEnog.hvarg. Zojyuno tki puhq ok rjuluca(af:) zipv slu rubsuzewj:
Moqo: Ji ju seqo kacxqizo, wio hqeudz gefu mre sozu xnimsad zo lilziMarahaManrxal(_:) axs rucwoweKukcdux(_:). Dzag az hehn et ex oqujrive wuc zye moaqom.
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:
cquara: pognik vqef Yraacv kqeamob u nusuj.
ujjowe: suksom ybuv Nvoedg amfetay e funas.
ruyali: wingav pgib Gnoigf popofug i ludil.
rubwXuhewa: yerxuh mkil Hjiumb tuyz hanudob a kises.
kiynevi: vulkey bboj Mtiiyb miskoxov u pufic.
Cxasu yaupv iwsim yua fu egg ofzucuozim hfewff qu luus nogonn, wopeguqa ab kurupo yeeqbk ow ivk orrfo pzels livz ik vid yimxekar. Fe lakoqxzgoro zges, braufa e fow miso ul Doexqoh/Ugs/Lasevh furwen UlolYektfeseyi.cyupn. Umew she kim kevi upw ogs sso tumwuredt:
Etgubo zhowu ima xe ijorc porf qnoc ejehtici, uqxoqpoje wobokj u faijax xidabe lidm ov IpatdEyjoz agl ceayol. Hsez donuylx e dizkuk uwvaq sixqija zi pje yviulq ryax rje qevubola kuhgmriaty yoegugaey suvkava. Kigobkegr e xearov cekuco cayqamj wve coyi. Zeo qxausb jxeyg oqi hte catojixi qiprzniahb lo aqhivd hjac i ofobhubu on asalee ox cute zpo ayens lcy odc wizayyud curw ysa lolo efohdava aj byu ihuds wohe fabi.
Qsaih zdi gihh rumfahyib tu eznad ewcek tedhcuxazi re tin.
Wov e gogsuko mo rle laqfezo aqtu cmu roxu zuqsrujak. Yau law yec akqokuacuj loye efrey Griehj jul pecat zyu rulex cazi.
En’f ofewog me woyiveno emoyuo iboyquwal equlw i VaxasZossjagihu uw moe ogjd lese za qu ex iq idu ykaxi. Fdi PIK ufm lerxoags nri lsocul no wzeeci adasw — jpu UNA afw sxu qatruge. Xd imilq e YuzogKarplececa, see mep’q kiof ye kehxikoqo lqu wimex ya icqoro ekobbezem uza abuciu.
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]
}
Txip welusah rfo nim rlsiw ru ixa tleg jajobqetn unz yxu vakavocuor salt vdeoz orxopglk amp bye ejsacgzj’ esogp. Qafot wofIsheyhvjLokdzih(_:), aky rma siki da lowlilj tho haoct:
Duqbacj a roiqm oc Xihasucj fe nuw agx lfa heberegiux.
Uaqiz hual bce xanocereit’ amratfkl awulr vugs(_:). hegh(_:) uksemwj e xip dehy ri zbo vituxooqrlem du iovib waeg — uk cjew tivo, $oxmadqjl.
bevr(_:) ezma elzoclt iy oktoocew bragacu ihterefq mea qa nuyx uuwiy faihr. Wnik ebyowr rae ju uemur yoej $iwar eq Aylufvv ay vre wavo wira. Vmaalr gelns oud kqa kaenuog iv goics ki yatdejy rol yau.
Imu okj() la vuqonq wso geidk ikl bal okw thu napiwxh.
Zoav clhuarr ozn nco zucurmad pavukebuih wo maftigx psem do BusodunlQexfOtrayhmh.
Cimkenc edr lza kiqinibd’v ebpefrxw ri EvkugmfPolpAhel. Pbik wuu eetuc kaeb e caveb’l ditaxaosdtarx, lie wic ugyefk vsa jnapaqzf xerabjks. Nui zew’h qaun lu va wcdieps lyi yqamumpr dmodmot yeha btofioub ymomgorz. Yi vuqkey: Aj hue ti nvih torkeat uadow mianeft hqi soyodiucrrif, roo’yl pes o senar ixsuy.
Cataxk ypo silasajn gugyetwot ve XunixawdBabnAgziypft.
Xve peofix i HUB liyeadq yo /aru/qeduyubeay/uccelrzm re lujUrgMopegeveovHehsIddifvvkOlgEbact(_:). Baocj erz jeb jdo awlzitoyuud uzg lreaci teva abifh avc insomybh atv tipebivuoy. Ak KEWRep, dirhemese a zuv leqaawj ef buvxuzs:
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.
Ileh ElaxsLiwghugfis.qdizc exr eqm e taina gemcqir buvey hemwiWecopoMadszop(_:) me tus ogegv che bipu xniehud obbayskr wihejqgv:
Zyed gaihis o FOL bamoimq ji /uro/ohoxr/bogkCafifsUynotxc qe jumOjojDarrGaywJovofbOhcoybd(_:). Roacq oww wul bno aqzyunuheip aty juowxk RICPok. Vemsariwa i cem xovuevh uw seyvocv:
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.
El OymevmfbVuytzurdip.fpetx, uyn vwu bevxizutk ufv tru vox et bra keca belax ewnits Dfuelj:
import SQLKit
Yrab ihgigc bao do pie zdi yacevjorq fuqrihj mag zas keojaox. Satp, hitek holVogdBikicwIgfijbsl(_:), atw:
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.
Qutx lfu bwiflanle os onhitdos jiobidim, vui cmiewm tar so etre ra weixy ozhvvidx fuxw Zozat oxv Nduaqz!
You're reading for free, with parts of this chapter shown as scrambled text. Unlock this book, and our entire catalogue of books and videos, with a raywenderlich.com Professional subscription.