Reading and Writing data

this guide will teach you how to create, read, update, and delete data objects on back4app using the parse sdk data storage on back4app revolves around the parse object class, which allows you to store key value pairs of json compatible data, providing flexibility and simplicity in data management objectives understand how to perform data manipulation (crud) on back4app using parse sdk learn how to set up and use the parse sdk across different platforms prerequisites app on back4app you need an app created on back4app guide to creating a new app https //www back4app com/docs/get started/new parse app parse sdk installation parse sdk installation guide https //www back4app com/docs/get started/parse sdk 1 creating parse objects to store data in back4app, you need to create a parseobject associated with a specific class for example, in a soccer related application, you could create a soccerplayers class to store data about players async function savenewplayer() { const soccerplayers = new parse object("soccerplayers"); soccerplayers set("playername", "a wed"); soccerplayers set("yearofbirth", 1997); soccerplayers set("emailcontact", "a wed\@email io"); soccerplayers set("attributes", \["fast", "good conditioning"]); try { const result = await soccerplayers save(); console log('new object created with objectid ' + result id); } catch (error) { console error('error ' + error message); } } flutter parseobject soccerplayers = parseobject('soccerplayers') set('playername', 'a wed') set('yearofbirth', 1997) set('emailcontact', 'a wed\@email io') set('attributes', \['fast', 'good conditioning']); parseresponse response = await soccerplayers save(); if (response success) { print('new object created with objectid ${response result objectid}'); } else { print('error ${response error message}'); } android parseobject soccerplayers = new parseobject("soccerplayers"); soccerplayers put("playername", "a wed"); soccerplayers put("yearofbirth", 1997); soccerplayers put("emailcontact", "a wed\@email io"); soccerplayers put("attributes", arrays aslist("fast", "good conditioning")); soccerplayers saveinbackground(e > { if (e == null) { log d("parse", "new object created with objectid " + soccerplayers getobjectid()); } else { log e("parseerror", e getmessage()); } }); ios let soccerplayer = parseobject(classname "soccerplayers") soccerplayer\["playername"] = "a wed" soccerplayer\["yearofbirth"] = 1997 soccerplayer\["emailcontact"] = "a wed\@email io" soccerplayer\["attributes"] = \["fast", "good conditioning"] soccerplayer save { result in switch result { case success(let savedplayer) print("new object created with objectid \\(savedplayer objectid!)") case failure(let error) print("error \\(error localizeddescription)") } } php $soccerplayers = new parseobject("soccerplayers"); $soccerplayers >set("playername", "a wed"); $soccerplayers >set("yearofbirth", 1997); $soccerplayers >set("emailcontact", "a wed\@email io"); $soccerplayers >setarray("attributes", \["fast", "good conditioning"]); try { $soccerplayers >save(); echo 'new object created with objectid ' $soccerplayers >getobjectid(); } catch (parseexception $ex) { echo 'error ' $ex >getmessage(); } net parseobject soccerplayers = new parseobject("soccerplayers"); soccerplayers\["playername"] = "a wed"; soccerplayers\["yearofbirth"] = 1997; soccerplayers\["emailcontact"] = "a wed\@email io"; soccerplayers\["attributes"] = new list\<string> { "fast", "good conditioning" }; await soccerplayers saveasync(); console writeline("new object created with objectid " + soccerplayers objectid); rest api curl x post \\ h "x parse application id application id" \\ h "x parse rest api key rest api key" \\ h "content type application/json" \\ d '{ "playername" "a wed", "yearofbirth" 1997, "emailcontact" "a wed\@email io", "attributes" \["fast", "good conditioning"] }' \\ https //parseapi back4app com/classes/soccerplayers after running this code, you can verify the new object in the database section of the back4app dashboard note that you don’t need to manually create the soccerplayers class; it will be created automatically the first time an object is saved 2 reading parse objects to retrieve saved data, you can use a parsequery for instance, to fetch the player created above by its objectid js async function retrieveplayer() { const query = new parse query("soccerplayers"); try { const player = await query get("hmctr9rd3s"); // replace with the actual objectid console log("player name " + player get("playername")); console log("year of birth " + player get("yearofbirth")); console log("email contact " + player get("emailcontact")); } catch (error) { console error("error retrieving object " + error message); } } flutter parseresponse response = await parseobject("soccerplayers") getobject("hmctr9rd3s"); // replace with the actual objectid if (response success) { parseobject player = response result; print("player name ${player get\<string>('playername')}"); print("year of birth ${player get\<int>('yearofbirth')}"); print("email contact ${player get\<string>('emailcontact')}"); } else { print("error retrieving object ${response error message}"); } android parsequery\<parseobject> query = parsequery getquery("soccerplayers"); query getinbackground("hmctr9rd3s", (player, e) > { // replace with the actual objectid if (e == null) { log d("parse", "player name " + player getstring("playername")); log d("parse", "year of birth " + player getint("yearofbirth")); log d("parse", "email contact " + player getstring("emailcontact")); } else { log e("parseerror", "error retrieving object " + e getmessage()); } }); ios let query = parsequery(classname "soccerplayers") query get(objectid "hmctr9rd3s") { result in // replace with the actual objectid switch result { case success(let player) print("player name \\(player\["playername"] ?? "no name")") print("year of birth \\(player\["yearofbirth"] ?? "no birth year")") print("email contact \\(player\["emailcontact"] ?? "no email")") case failure(let error) print("error retrieving object \\(error localizeddescription)") } } php $query = new parsequery("soccerplayers"); try { $player = $query >get("hmctr9rd3s"); // replace with the actual objectid echo "player name " $player >get("playername") "\n"; echo "year of birth " $player >get("yearofbirth") "\n"; echo "email contact " $player >get("emailcontact") "\n"; } catch (parseexception $ex) { echo 'error retrieving object ' $ex >getmessage(); } net var query = parseobject getquery("soccerplayers"); var player = await query getasync("hmctr9rd3s"); // replace with the actual objectid console writeline("player name " + player get\<string>("playername")); console writeline("year of birth " + player get\<int>("yearofbirth")); console writeline("email contact " + player get\<string>("emailcontact")); rest api curl x get \\ h "x parse application id application id" \\ h "x parse rest api key rest api key" \\ https //parseapi back4app com/classes/soccerplayers/hmctr9rd3s # replace with the actual objectid in addition to objectid , you can also query by other parameters (e g , yearofbirth , playername ), offering greater flexibility in data searches 3 updating parse objects to update an object, retrieve it first, set new values for the desired attributes, and call the save() method async function updateplayer() { const query = new parse query("soccerplayers"); try { const player = await query get("hmctr9rd3s"); // replace with the actual objectid player set("yearofbirth", 1998); await player save(); console log("object updated successfully!"); } catch (error) { console error("error updating object " + error message); } } flutter parseobject player = parseobject("soccerplayers") objectid = "hmctr9rd3s"; // replace with the actual objectid player set("yearofbirth", 1998); parseresponse response = await player save(); if (response success) { print("object updated successfully!"); } else { print("error updating object ${response error message}"); } android parsequery\<parseobject> query = parsequery getquery("soccerplayers"); query getinbackground("hmctr9rd3s", (player, e) > { // replace with the actual objectid if (e == null) { player put("yearofbirth", 1998); player saveinbackground(e1 > { if (e1 == null) { log d("parse", "object updated successfully!"); } else { log e("parseerror", "error updating object " + e1 getmessage()); } }); } else { log e("parseerror", "error retrieving object " + e getmessage()); } }); ios let query = parsequery(classname "soccerplayers") query get(objectid "hmctr9rd3s") { result in // replace with the actual objectid switch result { case success(var player) player\["yearofbirth"] = 1998 player save { saveresult in switch saveresult { case success print("object updated successfully!") case failure(let error) print("error updating object \\(error localizeddescription)") } } case failure(let error) print("error retrieving object \\(error localizeddescription)") } }$query = new parsequery("soccerplayers"); try { $player = $query >get("hmctr9rd3s"); // replace with the actual objectid $player >set("yearofbirth", 1998); $player >save(); echo "object updated successfully!"; } catch (parseexception $ex) { echo 'error updating object ' $ex >getmessage(); } net var query = parseobject getquery("soccerplayers"); var player = await query getasync("hmctr9rd3s"); // replace with the actual objectid player\["yearofbirth"] = 1998; await player saveasync(); console writeline("object updated successfully!"); rest api curl x put \\ h "x parse application id application id" \\ h "x parse rest api key rest api key" \\ h "content type application/json" \\ d '{"yearofbirth" 1998}' \\ https //parseapi back4app com/classes/soccerplayers/hmctr9rd3s # replace with the actual objectid 4 deleting parse objects to delete an object, retrieve it by objectid and use the destroy() method async function deleteplayer() { const query = new parse query("soccerplayers"); try { const player = await query get("hmctr9rd3s"); // replace with the actual objectid await player destroy(); console log("object deleted successfully!"); } catch (error) { console error("error deleting object " + error message); } } flutter parseobject player = parseobject("soccerplayers") objectid = "hmctr9rd3s"; // replace with the actual objectid parseresponse response = await player delete(); if (response success) { print("object deleted successfully!"); } else { print("error deleting object ${response error message}"); } android parsequery\<parseobject> query = parsequery getquery("soccerplayers"); query getinbackground("hmctr9rd3s", (player, e) > { // replace with the actual objectid if (e == null) { player deleteinbackground(e1 > { if (e1 == null) { log d("parse", "object deleted successfully!"); } else { log e("parseerror", "error deleting object " + e1 getmessage()); } }); } else { log e("parseerror", "error retrieving object " + e getmessage()); } }); ios let query = parsequery(classname "soccerplayers") query get(objectid "hmctr9rd3s") { result in // replace with the actual objectid switch result { case success(let player) player delete { deleteresult in switch deleteresult { case success print("object deleted successfully!") case failure(let error) print("error deleting object \\(error localizeddescription)") } } case failure(let error) print("error retrieving object \\(error localizeddescription)") } } php $query = new parsequery("soccerplayers"); try { $player = $query >get("hmctr9rd3s"); // replace with the actual objectid $player >destroy(); echo "object deleted successfully!"; } catch (parseexception $ex) { echo 'error deleting object ' $ex >getmessage(); } net var query = parseobject getquery("soccerplayers"); var player = await query getasync("hmctr9rd3s"); // replace with the actual objectid await player deleteasync(); console writeline("object deleted successfully!"); rest api curl x delete \\ h "x parse application id application id" \\ h "x parse rest api key rest api key" \\ https //parseapi back4app com/classes/soccerplayers/hmctr9rd3s # replace with the actual objectid again, you don’t have to retrieve the object by its objectid objectid parse has many search alternatives to retrieve information from parseobjects parseobjects , which you can find out more about in the official parse documentation for each distinct technology best practices and additional tips naming conventions use classnameslikethis for classes and keynameslikethis for keys to keep your code organized and readable common error checks if you experience issues connecting to the parse sdk, verify your sdk installation and configuration automatic fields remember that each parse object automatically includes createdat , updatedat , and objectid fields next steps after persisting save and reading your first data on back4app, we recommend keeping exploring the data storage using the guides below you will find how to store supported data types, save and query relational data, use geopoints, and create optimized data models react native flutter android ios javascript graphql reactjs conclusion this guide provides a solid starting point for working with data on back4app, making data storage and manipulation across platforms easy using the parse sdk for any questions, feel free to reach out to back4app support !