Vertiefte Datenabfragen in Flutter mit Parse.Query

parse query kochbuch in flutter einführung wir haben bereits gesehen, wie ein querybuilder querybuilder mit get get ein einzelnes parseobject parseobject von back4app abrufen kann es gibt viele andere möglichkeiten, daten mit querybuilder querybuilder abzurufen sie können viele objekte auf einmal abrufen, bedingungen für die objekte verwenden, die sie abrufen möchten, und mehr in diesem leitfaden werden sie tief in die querybuilder querybuilder klasse eintauchen und alle methoden sehen, die sie verwenden können, um ihre abfragen zu erstellen sie werden eine einfache datenbankklasse mit einigen simulierten daten verwenden, um die abfragen mit flutter auf back4app durchzuführen voraussetzungen android studio https //developer android com/studio oder vs code installiert (mit plugins dart und flutter) eine app erstellt auf back4app hinweis folgen sie dem neuen parse app tutorial , um zu lernen, wie man eine parse app auf back4app erstellt eine flutter app, die mit back4app verbunden ist hinweis folgen sie dem installieren sie das parse sdk im flutter projekt um ein flutter projekt zu erstellen, das mit back4app verbunden ist ein gerät (oder virtuelles gerät), das android oder ios ausführt ziel erforschen sie die querybuilder querybuilder klasse und deren verschiedene methoden die querybuilder klasse jede parse abfrageoperation verwendet den querybuilder querybuilder objekttyp, der ihnen hilft, spezifische daten aus ihrer datenbank in ihrer app abzurufen um einen neuen querybuilder querybuilder , müssen sie als parameter die gewünschte parseobject parseobject unterklasse übergeben, die die abfrageergebnisse enthalten wird es ist entscheidend zu wissen, dass ein querybuilder querybuilder nur nach dem aufruf einer abrufmethode query query , aufgelöst wird, sodass eine abfrage eingerichtet und mehrere modifikatoren verkettet werden können, bevor sie tatsächlich aufgerufen wird sie können mehr über die querybuilder klasse hier in der offiziellen dokumentation lesen verwendung der javascript konsole auf back4app in ihrem back4app anwendungs dashboard finden sie eine sehr nützliche api konsole, in der sie javascript code direkt ausführen können in diesem leitfaden verwenden sie sie, um datenobjekte in back4app zu speichern gehen sie auf ihrem haupt dashboard der app zu core >api console >javascript core >api console >javascript speichern sie ihre datenobjekte um die abfragen in diesem leitfaden auszuführen, müssen sie zunächst ihre app mit einigen daten füllen lassen sie uns eine beispielklasse namens profil profil , die eine social media profilklasse mit namen berühmter personen und den folgenden feldern simuliert string typ name name datentyp geburtstag geburtstag zahl (ganzzahl) typ freundezahl freundezahl array (string liste) typ lieblingsessen lieblingsessen array (zahlenliste) typ glückszahlen glückszahlen geopoint typ letzteanmeldestandort letzteanmeldestandort hier ist der parse object parse object klassen erstellungscode, also mach weiter und führe ihn in deiner api konsole aus 1 // add profile objects and create table 2 // adam sandler 3 let profile = new parse object('profile'); 4 profile set('name', 'adam sandler'); 5 profile set('birthday', new date('09/09/1966')); 6 profile set('friendcount', 2); 7 profile set('favoritefoods', \['lobster', 'bread']); 8 profile set('luckynumbers', \[2, 7]); 9 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 10 await profile save(); 11 12 // britney spears 13 profile = new parse object('profile'); 14 profile set('name', 'britney spears'); 15 profile set('birthday', new date('12/02/1981')); 16 profile set('friendcount', 52); 17 profile set('favoritefoods', \['cake', 'bread']); 18 profile set('luckynumbers', \[22, 7]); 19 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 20 await profile save(); 21 22 // carson kressley 23 profile = new parse object('profile'); 24 profile set('name', 'carson kressley'); 25 profile set('birthday', new date('11/11/1969')); 26 profile set('friendcount', 12); 27 profile set('favoritefoods', \['fish', 'cookies']); 28 profile set('luckynumbers', \[8, 2]); 29 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 30 await profile save(); 31 32 // dan aykroyd 33 // creates related object membership for this user only 34 let membership = new parse object('membership'); 35 membership set('name', 'premium'); 36 membership set('expirationdate', new date('10/10/2030')) 37 await membership save(); 38 39 profile = new parse object('profile'); 40 profile set('name', 'dan aykroyd'); 41 profile set('birthday', new date('07/01/1952')); 42 profile set('friendcount', 66); 43 profile set('favoritefoods', \['jam', 'peanut butter']); 44 profile set('luckynumbers', \[22, 77]); 45 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 46 profile set('premiummembership', membership); 47 await profile save(); 48 49 // eddie murphy 50 profile = new parse object('profile'); 51 profile set('name', 'eddie murphy'); 52 profile set('birthday', new date('04/03/1961')); 53 profile set('friendcount', 49); 54 profile set('favoritefoods', \['lettuce', 'pepper']); 55 profile set('luckynumbers', \[6, 5]); 56 profile set('lastloginlocation', new parse geopoint( 27 104919974838154, 52 61428045237739)); 57 await profile save(); 58 59 // fergie 60 profile = new parse object('profile'); 61 profile set('name', 'fergie'); 62 profile set('birthday', new date('03/27/1975')); 63 profile set('friendcount', 55); 64 profile set('favoritefoods', \['lobster', 'shrimp']); 65 profile set('luckynumbers', \[13, 7]); 66 profile set('lastloginlocation', new parse geopoint( 27 104919974838154, 52 61428045237739)); 67 await profile save(); 68 69 console log('success!'); nachdem sie diesen code ausgeführt haben, sollten sie jetzt eine profil profil klasse in ihrer datenbank mit sechs erstellten objekten haben ihre neue klasse sollte folgendermaßen aussehen lassen sie uns nun beispiele von jeder querybuilder querybuilder methode ansehen, zusammen mit kurzen erklärungen, was sie tun bitte beachten sie, dass einige methoden in dieser liste optionen optionen als zusätzliches argument annehmen können, aber in den meisten fällen bezieht es sich nur auf die masterkey masterkey nutzung und nicht auf den inhalt dieses leitfadens relevant ist, sodass diese möglichkeit weggelassen wird, wann immer sie nicht relevant ist abfrage retriever diese methoden sind dafür verantwortlich, die abfrage auszuführen und ihre ergebnisse abzurufen, und sind immer in ihrer abfrageimplementierung vorhanden count //retrieves the count of parseobject results that meet the query criteria 1 querybuilder\<parseobject> querybuilder = querybuilder\<parseobject>(parseobject('profile')); 2 var apiresponse = await queryplayers count(); 3 if (apiresponse success && apiresponse result != null) { 4 int countgames = apiresponse count; 5 } getobject //this quick method is used to retrieve a single parseobject instance when you know its objectid 1 ///to retrieve one object of a class it is not necessary to create a parsequery 2 ///we can query using parseobject 3 final apiresponse = await parseobject('profile') getobject('c6endlnfdq'); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var o in apiresponse results) { 7 final object = o as parseobject; 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } getall //retrieves a complete list of parseobjects 1 ///to retrieve all objects of a class it is not necessary to create a parsequery 2 ///we can query using parseobject 3 final apiresponse = await parseobject('profile') getall(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var o in apiresponse results) { 7 final object = o as parseobject; 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } query //this is the basic method for retrieving your query results, always returning an list of parseobject instances, being empty when none are found 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 // when using query() in a query without other operations, you will 3 // get every object saved in your class 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var o in apiresponse results) { 8 final object = o as parseobject; 9 print('${object objectid} ${object get\<string>('name')}'); 10 } 11 } abfragebedingungen diese methoden geben ihnen die möglichkeit, bedingte einschränkungen auf ihre abfrage anzuwenden, die arguably die wichtigsten operationen beim abfragen sind denken sie daran, dass all diese operationen verkettet werden können, bevor die ergebnisse abgerufen werden, sodass viele kombinationen erreicht werden können, um ihre abfragebedürfnisse zu lösen wheredoesnotmatchkeyinquery //requires that a key’s value does not match a value in an object returned by a different parse query useful for multi object querying 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wheredoesnotmatchkeyinquery( 3 'friendcount', 4 'friendcount', 5 querybuilder\<parseobject>(parseobject('profile')) 6 wherelessthan('friendcount', 50)); 7 parsequery wheregreaterthan('friendcount', 10); 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} friendcount ${object get\<int>('friendcount')}'); 13 } 14 } wherearraycontainsall //filters objects in which an array type key value must contain every value provided 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherearraycontainsall('luckynumbers', \[2, 7]); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} ${object get\<string>('name')}'); 8 } 9 } wherecoitainedin //filters objects in which a key value is contained in the provided array of values 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherecontainedin('luckynumbers', \[2, 7]); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} ${object get\<string>('name')}'); 8 } 9 } wherecontains //filters objects in which a string key value contains the provided text value be aware that this condition is case sensitive 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 // this can be slow in large databases 3 parsequery wherecontains('name', 'an'); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wheredoesnotmatchquery //requires that an object contained in the given key does not match another query useful for multi object querying 1 final querybuilder\<parseobject> innerquery = querybuilder\<parseobject>(parseobject('membership')); 2 innerquery wheregreaterthan('expirationdate', datetime now()); 3 4 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 5 6 parsequery wheredoesnotmatchquery('premiummembership', innerquery); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')}'); 13 } 14 } whereendswith //filters objects where specific key’s value ends with value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery whereendswith('name', 'ie'); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var o in apiresponse results) { 8 final object = o as parseobject; 9 print('${object objectid} ${object get\<string>('name')}'); 10 } 11 } whereequalto //filters objects in which a specific key’s value is equal to the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery whereequalto('friendcount', 2); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var o in apiresponse results) { 8 final object = o as parseobject; 9 print('${object objectid} ${object get\<string>('name')}'); 10 } 11 } wheregreaterthan //filters objects in which a specific key’s value is greater than the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wheregreaterthan('birthday', datetime(1980, 08, 19)); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wheregreaterthanorequalsto //filters objects in which a specific key’s value is greater than or equal to the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wheregreaterthanorequalsto('friendcount', 49); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wherelessthan //filters objects in which a specific key’s value is lesser than the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wherelessthan('birthday', datetime(1980, 08, 19)); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wherelessthanorequalto //filters objects in which a specific key’s value is lesser than or equal to the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wherelessthanorequalto('friendcount', 49); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wherematcheskeyinquery //requires that a key’s value matches a value in an object returned by a different parse query useful for multi object querying 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherematcheskeyinquery( 3 'friendcount', 4 'friendcount', 5 querybuilder\<parseobject>(parseobject('profile')) 6 wherelessthan('friendcount', 50)); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} friendcount ${object get\<int>('friendcount')}'); 13 } 14 } wherematchesquery //requires that an object contained in the given key matches another query useful for multi object querying 1 final querybuilder\<parseobject> innerquery = querybuilder\<parseobject>(parseobject('membership')); 2 innerquery wheregreaterthan('expirationdate', datetime now()); 3 4 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 5 6 parsequery wherevalueexists('premiummembership', true); 7 parsequery wherematchesquery('premiummembership', innerquery); 8 9 final apiresponse = await parsequery query(); 10 11 if (apiresponse success && apiresponse results != null) { 12 for (var object in apiresponse results as list\<parseobject>) { 13 print('${object objectid} name ${object get\<string>('name')}'); 14 } 15 } wherenotcontainedin //filters objects in which a key value is not contained in the provided array of values 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherenotcontainedin('luckynumbers', \[2, 7]); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} ${object get\<string>('name')}'); 8 } 9 } wherenotequalto //filters objects in which a specific key’s value is not equal to the provided value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wherenotequalto('friendcount', 2); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var object in apiresponse results as list\<parseobject>) { 8 print('${object objectid} ${object get\<string>('name')}'); 9 } 10 } wherestartswith //filters objects where specific key’s value starts with value 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 3 parsequery wherestartswith('name', 'adam'); 4 final apiresponse = await parsequery query(); 5 6 if (apiresponse success && apiresponse results != null) { 7 for (var o in apiresponse results) { 8 final object = o as parseobject; 9 print('${object objectid} ${object get\<string>('name')}'); 10 } 11 } wherevalueexists //filters objects in which a key value is set or no 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 //true retrieve documents with field set 3 //false retrieve documents without field set 4 parsequery wherevalueexists('premiummembership', true); 5 final apiresponse = await parsequery query(); 6 7 if (apiresponse success && apiresponse results != null) { 8 for (var object in apiresponse results as list\<parseobject>) { 9 print('${object objectid} ${object get\<string>('name')}'); 10 } 11 } abfrageordnung wesentlich in den meisten abfragen kann die ordnung in parse leicht erreicht und sogar zwischen zwei oder mehr ordnungsbedingungen verkettet werden orderbyascending //sort the results in ascending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery orderbyascending('name'); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} ${object get\<string>('name')}'); 8 } 9 } orderbydescending //sort the results in descending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery orderbydescending('name'); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} ${object get\<string>('name')}'); 8 } 9 } feldauswahl diese methoden beeinflussen, welche feldwerte in ihren abfrageergebnissen enthalten sein können excludekeys //return all fields in the returned objects except the ones specified 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery excludekeys(\['name']); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 //name = null 8 print('${object objectid} name ${object get\<string>('name')} birthday ${object get\<datetime>('birthday')}'); 9 } 10 } includeobject //includes nested parseobjects for the provided key 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery includeobject(\['premiummembership']); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 //name = null 8 print('${object objectid} name ${object get\<string>('name')} premiummembership ${object get\<parseobject>('premiummembership') tostring()}'); 9 } 10 } keystoreturn //return only the specified fields in the returned objects 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery keystoreturn(\['name']); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 //birthday = null 8 print('${object objectid} name ${object get\<string>('name')} birthday ${object get\<datetime>('birthday')}'); 9 } 10 } geopunktabfrage dies sind methoden, die spezifisch für geopoint abfragen sind wherenear //return all fields in the returned objects except the ones specified 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherenear( 3 'lastloginlocation', 4 parsegeopoint(latitude 37 38412167489413, longitude 122 01268034622319) 5 ); 6 7 final apiresponse = await parsequery query(); 8 9 if (apiresponse success && apiresponse results != null) { 10 for (var object in apiresponse results as list\<parseobject>) { 11 print('${object objectid} name ${object get\<string>('name')} geopoint ${object get\<parsegeopoint>('lastloginlocation') tojson()}'); 12 } 13 } wherewithingeobox 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherewithingeobox( 3 'lastloginlocation', 4 parsegeopoint(latitude 37 38412167489413, longitude 122 01268034622319), 5 parsegeopoint(latitude 37 28412167489413, longitude 121 91268034622319) 6 ); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} geopoint ${object get\<parsegeopoint>('lastloginlocation') tojson()}'); 13 } 14 } wherewithinkilometers 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherewithinkilometers( 3 'lastloginlocation', 4 parsegeopoint(latitude 37 38412167489413, longitude 122 01268034622319), 5 100 6 ); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} geopoint ${object get\<parsegeopoint>('lastloginlocation') tojson()}'); 13 } 14 } wherewithinmiles 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherewithinmiles( 3 'lastloginlocation', 4 parsegeopoint(latitude 37 38412167489413, longitude 122 01268034622319), 5 100 6 ); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} geopoint ${object get\<parsegeopoint>('lastloginlocation') tojson()}'); 13 } 14 } wherewithinradians 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery wherewithinradians( 3 'lastloginlocation', 4 parsegeopoint(latitude 37 38412167489413, longitude 122 01268034622319), 5 100 6 ); 7 8 final apiresponse = await parsequery query(); 9 10 if (apiresponse success && apiresponse results != null) { 11 for (var object in apiresponse results as list\<parseobject>) { 12 print('${object objectid} name ${object get\<string>('name')} geopoint ${object get\<parsegeopoint>('lastloginlocation') tojson()}'); 13 } 14 } pagination diese methoden beziehen sich auf pagination utilities, die nützlich sind für abfragen, die eine große anzahl von ergebnissen abrufen setamounttoskip 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery setamounttoskip(2); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} name ${object get\<string>('name')}'); 8 } 9 } setlimit 1 final querybuilder\<parseobject> parsequery = querybuilder\<parseobject>(parseobject('profile')); 2 parsequery setlimit(2); 3 final apiresponse = await parsequery query(); 4 5 if (apiresponse success && apiresponse results != null) { 6 for (var object in apiresponse results as list\<parseobject>) { 7 print('${object objectid} name ${object get\<string>('name')}'); 8 } 9 } kombinationsabfrage diese methoden erstellen kombinationsabfragen, die mehr als eine parsequery instanz kombinieren können, um komplexere ergebnisse zu erzielen or //compose a compound query that is the or of the passed queries 1 final querybuilder\<parseobject> query1 = querybuilder\<parseobject>(parseobject('profile')); 2 query1 wheregreaterthan('friendcount', 10); 3 4 final querybuilder\<parseobject> query2 = querybuilder\<parseobject>(parseobject('profile')); 5 query2 wherelessthan('friendcount', 50); 6 7 querybuilder\<parseobject> mainquery = querybuilder or( 8 parseobject("profile"), 9 \[query1, query2], 10 ); 11 12 final apiresponse = await mainquery query(); 13 14 if (apiresponse success && apiresponse results != null) { 15 for (var object in apiresponse results as list\<parseobject>) { 16 print('${object objectid} name ${object get\<string>('name')}'); 17 } 18 } fazit am ende dieses leitfadens haben sie gelernt, wie sie jede datenabfragemethode in parse durchführen im nächsten leitfaden erfahren sie mehr über komplexe parse abfragen in flutter