import {openDatabase, SQLResultSet} from '@amazon-devices/expo-sqlite';
import React, {useEffect, useState} from 'react';
import {Button, StyleSheet, Text, View} from 'react-native';
let db = openDatabase('database.db');
export const App = () => {
const [rows, setRows] = useState<any[][]>([]);
const [dbClosed, setDbClosed] = useState(false);
// データベースを作成します
useEffect(() => {
db.transaction((tx) => {
tx.executeSql(
'create table if not exists items (id integer primary key not null, done int, value text, floating double, int integer);',
);
});
}, []);
const handleSelectResult = (result: SQLResultSet) => {
if (result.rows.length > 0) {
const columnNames = Object.keys(result.rows._array[0]);
const allRows = result.rows._array.map(Object.values);
setRows([columnNames, ...allRows]);
} else {
setRows([]);
}
};
// データベースを開きます
const openDb = () => {
db = openDatabase('database.db');
db.transaction((tx) => {
tx.executeSql(
'create table if not exists items (id integer primary key not null, done int, value text, floating double, int integer);',
);
});
setDbClosed(false);
};
// データベースを同期的に閉じます
const closeDbSync = () => {
db.closeSync();
setDbClosed(true);
};
// データベースを非同期で閉じます
const closeDbAsync = async () => {
await db.closeAsync();
setDbClosed(true);
};
// 挿入操作を同期的に実行します
const transactionSync = () => {
db.transaction((tx) => {
const done = Math.round(Math.random());
const value = 'text-' + Date.now().toString().slice(-4);
const float = Number((Math.random() * 10).toFixed(2));
const int = Math.round(Math.random() * 1000);
tx.executeSql(
'insert into items (done, value, floating, int) values (?, ?, ?, ?)',
[done, value, float, int],
() => {},
);
});
};
// 削除操作を非同期で実行します
const transactionAsync = async () => {
await db.transactionAsync(async (tx) => {
await tx.executeSqlAsync(
'delete from items where id = (select max(id) from items)',
);
});
};
// 選択トランザクションを同期的に実行します
const readTransactionSync = () => {
db.readTransaction((tx) => {
tx.executeSql('select * from items', [], (_, result) =>
handleSelectResult(result),
);
});
};
// データベースを削除する
const deleteDb = () => {
db.deleteAsync();
};
return (
<View style={styles.container}>
<View style={styles.sideColumn}>
<Button title="open" onPress={openDb} disabled={!dbClosed} />
<Button title="close sync" onPress={closeDbSync} disabled={dbClosed} />
<Button
title="close async"
onPress={closeDbAsync}
disabled={dbClosed}
/>
<Button
title="transaction sync (insert)"
onPress={transactionSync}
disabled={dbClosed}
/>
<Button
title="transaction async (delete)"
onPress={transactionAsync}
disabled={dbClosed}
/>
<Button
title="同期的な読み取りトランザクション(選択)"
onPress={readTransactionSync}
disabled={dbClosed}
/>
<Button
title="データベースを削除"
onPress={deleteDb}
disabled={!dbClosed}
/>
</View>
<View style={styles.mainColumn}>
<Text style={styles.label}>Database version: {db.version}</Text>
<Text style={styles.label}>Database open: {String(!dbClosed)}</Text>
<View style={styles.table}>
{rows.map((row) => (
<View style={styles.row}>
{row.map((col) => (
<View style={styles.cell}>
<Text style={styles.cellText}>{String(col)}</Text>
</View>
))}
</View>
))}
</View>
</View>
</View>
);
};
const styles = StyleSheet.create({
scrollView: {
flex: 1,
},
container: {
flex: 1,
backgroundColor: 'white',
flexDirection: 'row',
padding: 20,
},
sideColumn: {
flex: 1,
flexDirection: 'column',
padding: 10,
},
mainColumn: {
flex: 2,
flexDirection: 'column',
padding: 10,
},
label: {
color: 'black',
fontSize: 32,
flexDirection: 'column',
},
table: {
alignItems: 'center',
justifyContent: 'center',
},
row: {
flexDirection: 'row',
height: 40,
},
cell: {
flex: 1,
borderColor: 'black',
borderWidth: 1,
alignItems: 'center',
justifyContent: 'center',
},
cellText: {
color: 'black',
fontSize: 20,
},
});