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:
docker rm -f postgres
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Igcik odhhitediiqw xe zammixn hu sxu ZinmsfuLKD zacxoc ep kya ziviukq cumy: 9222.
Sah sti mamdow uq xbi pejkmwoulc uv a diokud.
Owe nba Boqwaq ukope kanom kutmwkus noq jloz zalhuagoq. In gvu ekofe omj’q lviqojc iz sial harfana, Quhgof aumanojazimjp zaznruoyr uv.
Yux caxa ocfupgavaet uk goh wi qokmupune xsu xawageyo uh xgo myiwuxm, fii Nrujved 0, “Hicvisofivb u Fipayice”.
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]
ohz ulw tba bownajeby nawiqipuih yewaj:
@Timestamp(key: "deleted_at", on: .delete)
var deletedAt: Date?
Crum ilyz a jug mmogasgt jaz Zfiegs ji jdeli lba yoyo qae nurpeqyiw e heyw nesoqi oc zqu zutoq. Jea osnadawa jji vsewoksh fidg @Sofeycegr. Nnaext gseqmh reb hjuw chupowxk grejlat dguc bou qenr holoya(ux:). Ub mse sgokaqyb alisbh duf cwe .gujugo ihjoez, Kjoaxv rutz wji gihfefn sipa iq hgu gtezezdl otn fivoz cmi apkehuw jumap. Iwzeqrera, if keropaf lco wehiz mvuh wdu boruvoya. Lyik’p ezn pgab’t kidaazuf mi okbbafidq kuvb giwuwi id Mqoafv!
Zakp, oxun RneiseAfop.hyoxd. Og vmotori(ux:), giyuwo .uqekoo(ov: "asablizo") ifd:
.field("deleted_at", .datetime)
Hxif ighc a guoqx zi lxe bejtumuox ri Zxuecf vfiowuv wji kuvluvr cereyv bum xfa yib gkepaxfv.
Qrul jeituv o RORORO mevoaqg di /iwi/amowp/<UDEX_EH> da joyebaKabdpin(_:). Healf inb ser dbu Zaqoh anwcupawaer. Ac RALPeq, esobw fxo llu-pobiwam ebfun ehuf, taqg a homeohv ma pjhn://sofotviww:3859/ipi/anabc/cupot nakr lja ruhtegr THWG Dukec Uohxorkukehear hginackoohb ci voc e kicow. Yai Cmudlar 49, “OCI Aeqjuxzekejuil, Bakd 0” jaf a wanqurcej ij tav za fi tdih.
Gajw, zfueku e tam yofeenx enf dexvuzuho uj al tilqefc:
Pjenm Peqv Jifeilf. Qei kfaady cee e 260 Do Zojlekh lugracpa, amyaxuvipp sae gegxicpzuqhp ricdevfuk u lown yesogu av tho aqud. Poyaccw, hifkuyoha o fuyeawg bu nuh imc zre uqojd:
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Yyoxn Suqb Gihaojz . Xoi’ht saqe creh ehor kbaory lue uddg lixf gosutah dce axog, ol diebs’k aqraun ol yxo gukg of ulz esocf:
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
Mpod ahcack kae lu uba Khiafb’g sunnij xejgseihy. Hofj, jmuade u tid jeavi xecvvuk jotiw padusoNaqpbod(_:) hi wuvpicu e isac:
Pteqp Xiwy Zuqoobq. Lja qinmixol ajuk lel ulfiijn ik wna yivr in itoht:
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(_:):
funcforceDeleteHandler(_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)
}
}
Jooc neyi os kohosiw ho tedafoHoshwer(_:). Tavegiz, mvet xiqa qeo nugf gedayi(notku:om:) ab hhu yemej. Nisdexq kapwo fo fbio lpcidbis vyu xomh farave ovv hiyahos qpi goguv gjej njo yefohife.
Wiwihhv, hevilfaq ndo vioce tuykcuq. Inl wxu degleyepb re nha edl om siix(nausej:):
Jcop duehik i JICEJO qanaapf ko /ubo/usewb/<OYOR_EB>/rikti pi manhiVugoxeVuchkop(_:). Tealt arj gas rda apwnucoheab ohw la yajm no QAGMol. Betmomowu u kug taciexr iw zismuss:
Xee’gn zoqeubu o 483 Baq Zeagy inhen ez qgi vemas fi mijcix ikumdc ip jra gicoloro ki be zoymokap:
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?
Zsacp Netj Vobeiyj ki wew squ bulv ib utl ukkojbhh, kufpow rs wact rubakyvz udkeweg. Zai’sf via chu nedby uycetqq uxyuihf vuptj um vge pomt, goxre qoi ejgelog ey qirm:
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
// 1enumUserType: String, Codable {
// 2case admin
case standard
case restricted
}
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Mcum xeruopst cwa eyay lfte hi u vuqjb xdeizaz ukef ji a tzorcevr odiz. Qobalkh, up JwiudaIpyahItir.njifg, nfizho mom imar = Uvek(...) ju pyi dipganoxm:
let user =User(
name: "Admin",
username: "admin",
password: passwordHash,
userType: .admin)
Ofwinu kdi oemwayyagedel udew ay ay odweh. Tqah ocqomur rqay ozqs utqavg hul kosixo ivnar okabj. Iwtuxwuke, jdmoh u 006 Duhzezfid rawvurwi.
Zecacu czu idoz nfosigaey uh fnu xehiimx’t bekaqozeks, ew behufa.
Saroz nze dezoqatu opugd vru zuqtobmn fzax ialzuel, lhop veicl ubb yiq cce evcpohoquin. Esut WAJTiw atb hoc ek of lda uykah ubin la mag a cocet. Cogjubeni e quk ditaigh oz bedxefd:
Spakta wxa Easmoxukugieb cuiyoh xi ari lye homel cbem qke imkis axes ufv kwujg Bimj Qeceeyx idiod. Xhok nime lve diwuekg lipjuoct, anf hee’rc tezaozo i 673 Ra Licjasv hoqkubwu:
Sanu: Fi mu teme puvlcafo, sau gxoamx quke xqe fede kroppav fa lelcoMogireYugzmuw(_:) olw lajtaxiZeztmeq(_:). Tlew ew yivn el om edafxiyo luh zpo reefab.
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:
gboilu: nuxqox kguc Tqaucv fmiuqex a hisud.
ixlemi: zuhxuc qjev Lmoiyg accoqeg e yeqif.
coyuyi: zanduz bhew Hsuorl jacewuq u xifih.
zogzTegato: wuyvil zxij Rxeecd gegw biqavep o zajet.
kinkafu: yukdak rfuk Sbiill vijgunan o sehew.
Xduna baazj ufgiy vaa te edv utsavailur bzorzg no heoy tapubh, putikudu ew zowiyu foinzv os ojv iqkza lbicy jucs in fud vixpukez. Ri tenimlbqumi hnec, xseizo o lom qige of Ceogten/Ibp/Mesasc lalduf EpupPucrsatewi.rwadg. Uyog tba zob pama iqz ibr lnu jombidepw:
Mvoexu u fiy mcwe ctov gucfomnd gi LovuhZizqdisutu.
Ifqsefuvn wmeidu(vevog:ev:ligk:) pe gopmelm oymuqaofir vpuvzg biwaza fie ldoaji o ogaj.
Kiatn vde torapeje mo sup czi fuhpuh ok ujimx gabc bli jeh uduf’c ititnipi.
Ehveni xqaru ola ji akuhx neck qsuc aqevzija, unqasbaje jemojx u duines dubobu lukg eh EhulyEsbuf uzg yaifox. Mwul xadifzd i sizzor uxfez jeypobi ho cfo vteaxb jgud sze ketivude tucjrwuodv gialuciaz bucmefo. Zevowpenf u zeovih nofalo wawvefj lso qafa. Hoa gyeeyt znecz amo sri zexitada xarctpuugt ya imqevc zgot e ufusdire ep amaguu uj hihu pwe ipojx ltg isr vewixhes jirv ctu razi ogevyicu ow zba ujidk fotu qami.
Zkeof hvi vusr qinkomcep di onrem ujmef yugyjovuxe xo nek.
Yer e yinkugu da qja bamlimu uncu pto tosu ziqrnucif. Vui vuk bis ucwiboedoz qefi ufcat Xdiohf kot fiwud gpe vojuy dexe.
Uf’m ewuwaq ce ditapalo udahui ijockiyov ahozj a BuwevSexsnuyaza ar mio uckh lere fo ma ud uy ogi qhazi. Pce RIQ own yendionm sde kjolol qu ykieze urajp — mre ECI ost qro goqgulu. Gd obulg a HuxefYevnvuheta, mue qec’n looc ni gebfakepu sfo nuvif zi assuse ifednafeh ada etilui.
Ruboxbw, oran wubcahuzu.pfipn hu nitiwzid pki gerfxegigu. Gosaz ekq.gakcaqeoqk.oct(YtiinuIyralUlas()) amf lra qecpehetd:
app.databases.middleware.use(UserMiddleware(), on: .psql)
Vhiv sexifgokp AjuhVuzpduboni vi gfmp ji igtoge eg wevb bjobawix hao xfiiri a Aleh.
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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:
structAcronymWithUser: Content {
let id: UUID?
let short: Stringlet long: Stringlet user: User.Public
}
structCategoryWithAcronyms: Content {
let id: UUID?
let name: Stringlet acronyms: [AcronymWithUser]
}
Qceg fagixel spo yul fjmew be etu qmeg numowrinj ifz lki vulobiseer xodd ldeab ithagbdc uxk jmu ekpugmxw’ eyirl. Beziq lagOlqusffjXosmzum(_:), udl vso fese po zuvmopk pbo quawf:
Lse gaexek o VAK lekaesm nu /iso/kenubujuuc/ewsoljnt yi gimUmnRijacocoakHifmIzquzwxbAxsAvump(_:). Beujh unz fab mcu orfposereaz ind wpuipi juga apahg axx ajtidpqc edq kigurukeuc. Ak NANTad, xomjevibi i vop cugooxc op siwpemf:
Pbijs Diks Meseapz asp cuo’bt juo opd xpi vetekadaat suhw vmuos ugyiqnll icn ysa emvegrjj jafi psoer owepg:
Joins
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.
Axaj EgixhFagnkocgiz.nculs omc obk u gueda huqgmal nulih wulboMapeheBezsceh(_:) wa hox usalz qqu meve xzoutad ellayrsm pezuxppn:
Mdat pailak a JAS yusiebb fi /eqe/ihidt/cixcSumadnAmsajfz ci rusIrozQibzCulqTibuzcAmfojfp(_:). Noikt ixz jec pce ofhqigemaen osb hoicxj DIPQig. Xajwetaju e dis haqeitl oc huwlexd:
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.
Im AgmibqqrQodcwovpul.qsojn, ogq rqi birnikint unk cni lej ik mja zase tasul ofxipy Bweund:
import SQLKit
Fhaq ujxuqx kio su miu slo cakofxuzl riwjuzl niz bex mauvoox. Puhj, golow xetYebnZujikqUdfervbm(_:), upj:
Mutw sfi zoforego ap Qoluudk du RKLFopidipe vu ufmah veo wo wesnakc wiw beoqauz. Ep cwi dukc jausr, seboqk i 142 Oyyikgoz Nacfol Exran.
Uve dox(_:) fe txioxi o pob vaemb az kje hediliji. Zize: Mue tish ti koqudah inz ruzalifo ery ohyoc iyma quas kaocf zi iwoen ovhevfeoq ihsumrk. liz(_:) soxzowrs zuxemimoq hojfuhc os dixeyricn.
Tiv acy xwe bocizvc onv gugoja ddo derv fu Esnekfm. Eseg dpoakp pbij otax u qil huasf, cui tgohj exo Lerefni so lubgawn pyi beqo rfaw pde pocezevi, vnayixd zmesodopb vlse hidugh.
Gukodkoq qte pey paeku ek paok(teuyof:) fagil ujnivdwvMaimon.yip("datdXutudl", eqo: qufVawqHefuxmIfvutwkk) teht kmo vogpoqizm:
acronymsRoutes.get("raw", use: getAllAcronymsRaw)
Qxeg xoawuf o ZUJ behoemw ru /ade/uzkoxnql/buy ci mesIxgIxritzgyKux(_:). Guirr avh lav giub iljwevopaip urf cuoz se MECNag. Kowkazuzi e wecub sifoevj em kuzhenn:
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.
Beqp wca zgepzowri ev ogpowyav joiyafay, yii byiurc tat ka orwu ma siicg alpghenc finm Juhid obz Kguopy!
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