docs.sheetjs.com/docz/static/mariadb/SheetJSMariaDB.js

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2023-12-05 03:46:54 +00:00
const mysql = require("mysql2/promise");
const XLSX = require("xlsx");
const opts = {
database:"SheetJSMariaDB",
host: "127.0.0.1", // localhost
port: 3306,
user: "sheetjs",
//password: ""
};
/* create table and load data given an array of objects and a mysql2 connection */
async function aoo_to_mariadb_table(conn, aoo, table_name) {
/* define types that can be converted (e.g. boolean can be stored in float) */
const T_FLOAT = ["DOUBLE", "BOOLEAN"];
const T_BOOL = ["BOOLEAN"];
/* types is a map from column headers to Knex schema column type */
const types = {};
/* names is an ordered list of the column header names */
const names = [];
/* loop across each row object */
aoo.forEach(row =>
/* Object.entries returns a row of [key, value] pairs */
Object.entries(row).forEach(([k,v]) => {
/* If this is first occurrence, mark unknown and append header to names */
if(!types[k]) { types[k] = ""; names.push(k); }
/* skip null and undefined values */
if(v == null) return;
/* check and resolve type */
switch(typeof v) {
/* change type if it is empty or can be stored in a float */
case "number": if(!types[k] || T_FLOAT.includes(types[k])) types[k] = "DOUBLE"; break;
/* change type if it is empty or can be stored in a boolean */
case "boolean": if(!types[k] || T_BOOL.includes(types[k])) types[k] = "BOOLEAN"; break;
/* no other type can hold strings */
case "string": types[k] = "TEXT"; break;
default: types[k] = "TEXT"; break;
}
})
);
const I = (id) => mysql.escapeId(id), E = (d) => mysql.escape(d);
/* Delete table if it exists in the DB */
await conn.execute(`DROP TABLE IF EXISTS ${I(table_name)};`);
/* Create table */
{
const Istr = Object.entries(types).map(e => `${I(e[0])} ${e[1]}`).join(", ");
await conn.execute(`CREATE TABLE ${I(table_name)} (${Istr});`);
}
/* Insert each row */
for(let row of aoo) {
const ent = Object.entries(row);
const Istr = ent.map(e => I(e[0])).join(", ");
const Vstr = ent.map(e => E(e[1])).join(", ");
await conn.execute(`INSERT INTO ${I(table_name)} (${Istr}) VALUES (${Vstr})`);
}
return conn;
}
(async() => {
/* read file and get first worksheet */
const oldwb = XLSX.readFile("pres.numbers");
const oldws = oldwb.Sheets[oldwb.SheetNames[0]];
/* import data to mariadb */
let conn = await mysql.createConnection(opts);
try {
/* generate array of objects from worksheet */
const aoo = XLSX.utils.sheet_to_json(oldws);
/* create table and load data */
await aoo_to_mariadb_table(conn, aoo, "Presidents");
} finally {
/* disconnect */
await conn.end();
}
/* export data to xlsx */
conn = await mysql.createConnection(opts);
try {
/* fetch all data from specified table */
const [ rows ] = await conn.execute(`SELECT * FROM ${mysql.escapeId("Presidents")}`);
/* export to file */
const newws = XLSX.utils.json_to_sheet(rows);
const newwb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(newwb, newws, "Export");
XLSX.writeFile(newwb, "SheetJSMariaDBExport.xlsx");
} finally {
/* disconnect */
await conn.end();
}
})();