Bulk queries with promises
Implementing a Promise function we can recurvise execute a list of queries to a data base. This function wait for the response of each query for execute the next of the list.
Array
This is the array of queries to do
le queries = [ `INSERT IGNORE INTO keywords ( name ) VALUES ( 'keyword')`, `INSERT IGNORE INTO tip_keywords ( tip_id, keyword_id ) VALUES ( '1', 'keyword' )` ];
Function
This function implements a Promise pattern
const queriesExecute = (q, index = 0) => {
let queries = q;
new Promise(function(resolve, reject) {
console.log(queries[index]);
connection.query(queries[index], (err, row) => {
if (err) {
reject(err);
} else {
console.log(`Keyword added!`.green);
resolve(row);
}
});
})
.then(data => {
if (index < queries.length - 1) {
index++;
queriesExecute(queries, index);
} else {
connection.end();
}
})
.catch(err => {
queryError(err, query);
});
};
Full example
This example get the key from param and edit the secon query with an Helper function.
'use strict';
const db = require('./DataBase')();
const connection = db.connect();
const tip = process.argv[3];
const keyword = process.argv[4];
const queryError = (err, query) => {
console.log(`Error while performing Query:`.red);
console.log(`${query}`.yellow);
console.log(`${err}`.red);
connection.end();
};
const queriesExecute = (q, index = 0) => {
let queries = q;
new Promise(function(resolve, reject) {
console.log(queries[index]);
connection.query(queries[index], (err, row) => {
if (err) {
reject(err);
} else {
console.log(`Keyword "${keyword}" added!`.green);
resolve(row);
}
});
})
.then(data => {
if (index < queries.length - 1) {
index++;
queryHelper(queries, index, {id: data.insertId});
queriesExecute(queries, index);
} else {
connection.end();
}
})
.catch(err => {
queryError(err, query);
});
};
const queryHelper = (query, index, data) => {
query[index] = query[index].replace('%KEYWORD_ID%', data.id);
return query;
};
queriesExecute([
`INSERT IGNORE INTO keywords ( name ) VALUES ( '${keyword}')`,
`INSERT IGNORE INTO tip_keywords ( tip_id, keyword_id ) VALUES ( '${tip}', '%KEYWORD_ID%' )`
]);