reactnative:db:sqlite
差分
この文書の現在のバージョンと選択したバージョンの差分を表示します。
| 次のリビジョン | 前のリビジョン | ||
|
reactnative:db:sqlite [2019/01/27 14:43] ips 作成 |
reactnative:db:sqlite [2019/02/22 00:55] (現在) ips |
||
|---|---|---|---|
| ライン 1: | ライン 1: | ||
| ====== SQLite ====== | ====== SQLite ====== | ||
| + | |||
| + | expoに含まれるデータベース | ||
| + | [[https://docs.expo.io/versions/latest/sdk/sqlite/|SQLite]] | ||
| + | |||
| + | [[https://www.dbonline.jp/sqlite/|SQLite入門]] | ||
| + | |||
| + | ===== 基本 ===== | ||
| + | |||
| + | 当たり前だが、パラメーター変数(？置換え)を使用する場合は、順番に気をつける必要がある。。。 | ||
| + | |||
| + | <code> | ||
| + | import { Constants, SQLite } from 'expo'; | ||
| + | |||
| + | const db = SQLite.openDatabase('SampleDatabase.db'); | ||
| + | |||
| + | ・・・ | ||
| + | componentDidMount(e){ | ||
| + | |||
| + | db.transaction(tx => { | ||
| + | tx.executeSql( | ||
| + | 'create table if not exists items (id integer primary key not null, done int, value text);' | ||
| + | ); | ||
| + | }); | ||
| + | |||
| + | db.transaction( | ||
| + | tx => { | ||
| + | tx.executeSql('insert into items (done, value) values (0, ?)', ["safa"]); | ||
| + | tx.executeSql('select * from items', [], (_, { rows }) => | ||
| + | console.log(JSON.stringify(rows)) | ||
| + | ); | ||
| + | }, | ||
| + | null, | ||
| + | console.log("test") | ||
| + | ); | ||
| + | |||
| + | </code> | ||
| + | |||
| + | ==== executeSql ==== | ||
| + | |||
| + | tx.executeSql(sqlStatement, arguments, successコールバック関数, errorコールバック関数) | ||
| + | sqlStatement:SQL | ||
| + | arguments:SQLに?を使用すると、置換え変数にできる。(プリペアードステートメント) | ||
| + | success,error:それぞれ自身のトランザクションと、結果の２つのパラメータが返る。 | ||
| + | <code> | ||
| + | executeSql = async (sql, params = []) => { | ||
| + | return new Promise((resolve, reject) => db.transaction(tx => { | ||
| + | tx.executeSql( sql , params, (_, { rows }) => | ||
| + | { | ||
| + | console.log("sql done"), | ||
| + | //resolve(rows._array) | ||
| + | resolve(rows.length) | ||
| + | } | ||
| + | , reject) | ||
| + | })) | ||
| + | } | ||
| + | | ||
| + | async componentDidMount(e){ | ||
| + | |||
| + | //成功コールバック関数 | ||
| + | let suc=function(){ | ||
| + | console.log("success") | ||
| + | } | ||
| + | | ||
| + | //エラーコールバック関数 | ||
| + | let fai=function(){ | ||
| + | console.log("fail") | ||
| + | } | ||
| + | |||
| + | console.log("----- start -----") | ||
| + | await this.executeSql('select * from items',[]).then((val)=>console.log("resulat=" + val)) | ||
| + | .catch(()=>console.log("err")) | ||
| + | console.log("----- end -----") | ||
| + | | ||
| + | [00:43:58] ----- start ----- | ||
| + | [00:43:58] sql done | ||
| + | [00:43:58] resulat=0 | ||
| + | [00:43:58] ----- end ----- | ||
| + | </code> | ||
| + | |||
| + | ==== ROWID ==== | ||
| + | |||
| + | SQLiteにはデータをINSERTすると自動でROWIDがつく。 | ||
| + | SELECTでは明記しないと取得できないので注意。 | ||
| + | |||
| + | [[https://www.sqlite.org/autoinc.html|SQLite Autoincrement]] | ||
| + | |||
| + | [[https://www.dbonline.jp/sqlite/table/index8.html|ROWIDの利用]] | ||
| + | |||
| + | <code> | ||
| + | db.transaction( | ||
| + | tx => { | ||
| + | tx.executeSql('select *,ROWID from items', [], (_, { rows }) => { | ||
| + | console.log(JSON.stringify(rows)) | ||
| + | console.log({count:rows.length}) | ||
| + | } | ||
| + | ); | ||
| + | }, | ||
| + | null, | ||
| + | ); | ||
| + | </code> | ||
| + | |||
| + | ==== await/asycnするためには？ ==== | ||
| + | [[https://stackoverflow.com/questions/47345000/react-native-handling-async-calls-to-sqllite-db|React Native : Handling Async calls to sqllite db]] | ||
| + | |||
| + | excuteはコールバックしているので、Promiseを返すようにする必要がある。 | ||
| + | <code> | ||
| + | |||
| + | executeSql = async (sql, params = []) => { | ||
| + | return new Promise((resolve, reject) => db.transaction(tx => { | ||
| + | tx.executeSql('select * from items', [], (_, { rows }) => | ||
| + | { | ||
| + | console.log("sql done"), | ||
| + | resolve(rows._array) | ||
| + | } | ||
| + | , reject) | ||
| + | })) | ||
| + | |||
| + | |||
| + | console.log("----- start -----") | ||
| + | await this.executeSql(null,null) | ||
| + | console.log("----- end -----") | ||
| + | |||
| + | [08:05:41] ----- start ----- | ||
| + | [08:05:41] sql done | ||
| + | [08:05:41] ----- end ----- | ||
| + | </code> | ||
| + | |||
| + | ===== 以下だだのメモ ===== | ||
| + | |||
| + | |||
| + | <code> | ||
| + | |||
| + | //db.transaction(callback, error, success) | ||
| + | console.log("----- drop start -----") | ||
| + | db.transaction((tx)=>{console.log("callback")}, console.log("error"), console.log("success")) | ||
| + | console.log("----- drop end -----") | ||
| + | | ||
| + | [06:56:31] ----- drop start ----- | ||
| + | [06:56:31] error | ||
| + | [06:56:31] success | ||
| + | [06:56:31] ----- drop end ----- | ||
| + | [06:56:31] callback | ||
| + | | ||
| + | </code> | ||
| + | executeSql = async (sql, params = []) => { | ||
| + | return new Promise((resolve, reject) => db.transaction(tx => { | ||
| + | tx.executeSql('select * from items', [], (_, { rows }) => | ||
| + | { | ||
| + | console.log("sql done"), | ||
| + | resolve(rows._array) | ||
| + | } | ||
| + | , reject) | ||
| + | })) | ||
| + | } | ||
| + | | ||
| + | | ||
| + | <code> | ||
| + | |||
| + | async getDB(){ | ||
| + | await db.transaction((tx)=>{return "callback"}, console.log("error"), console.log("success")) | ||
| + | } | ||
| + | | ||
| + | async componentDidMount(e){ | ||
| + | |||
| + | // db.transaction(callback, error, success) | ||
| + | console.log("----- drop start -----") | ||
| + | await console.log(this.getDB()) | ||
| + | console.log("----- drop end -----") | ||
| + | } | ||
| + | | ||
| + | [07:12:05] ----- drop start ----- | ||
| + | [07:12:05] error | ||
| + | [07:12:05] success | ||
| + | [07:12:05] Promise { | ||
| + | [07:12:05] "_40": 0, | ||
| + | [07:12:05] "_55": null, | ||
| + | [07:12:05] "_65": 0, | ||
| + | [07:12:05] "_72": null, | ||
| + | [07:12:05] } | ||
| + | [07:12:05] ----- drop end ----- | ||
| + | </code> | ||
reactnative/db/sqlite.1548567824.txt.gz · 最終更新: 2019/01/27 14:43 by ips
