Related
I'm currently developing a desktop application with Node-webkit. During that process I need to get some data from a local MySQL-database.
The querying works fine, but I can't figure out how to access the results. I store all of them in an array that is then passed to a function. In the console they look like this:
RowDataPacket {user_id: 101, ActionsPerformed: 20}
RowDataPacket {user_id: 102, ActionsPerformed: 110}
RowDataPacket {user_id: 104, ActionsPerformed: 3}
And here is the query structure:
var ret = [];
conn.query(SQLquery, function(err, rows, fields) {
if (err)
alert("...");
else {
for (var i of rows)
ret.push(i);
}
doStuffwithTheResult(ret);
}
How do I retrieve this in the doStuffwithTheResult function? The values are more important, but if I could get the keys as well that would be great.
Turns out they are normal objects and you can access them through user_id.
RowDataPacket is actually the name of the constructor function that creates an object, it would look like this new RowDataPacket(user_id, ...). You can check by accessing its name [0].constructor.name
If the result is an array, you would have to use [0].user_id.
With Object.prototype approach, JSON.parse(JSON.stringify(rows)) returns object, extract values with Object.values()
let result = Object.values(JSON.parse(JSON.stringify(rows)));
Usage:
result.forEach((v) => console.log(v));
I also met the same problem recently, when I use waterline in express project for complex queries ,use the SQL statement to query.
this is my solution: first transform the return value(RowDataPacket object) into string, and then convert this string into the json object.
The following is code :
//select all user (查询全部用户)
find: function(req, res, next){
console.log("i am in user find list");
var sql="select * from tb_user";
req.models.tb_user.query(sql,function(err, results) {
console.log('>> results: ', results );
var string=JSON.stringify(results);
console.log('>> string: ', string );
var json = JSON.parse(string);
console.log('>> json: ', json);
console.log('>> user.name: ', json[0].name);
req.list = json;
next();
});
}
The following is console:
>> results: [ RowDataPacket {
user_id: '2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5',
name: 'wuwanyu',
psw: '123',
school: 'Northeastern university',
major: 'Communication engineering',
points: '10',
datems: '1450514441486',
createdAt: Sat Dec 19 2015 16:42:31 GMT+0800 (中国标准时间),
updatedAt: Sat Dec 19 2015 16:42:31 GMT+0800 (中国标准时间),
ID: 3,
phone: 2147483647 } ]
>> string: [{"user_id":"2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5","name":"wuwanyu","psw":"123","school":"Northeastern university","major":"Communication engineering","points":"10","datems":"1450514
441486","createdAt":"2015-12-19T08:42:31.000Z","updatedAt":"2015-12-19T08:42:31.000Z","ID":3,"phone":2147483647}]
>> json: [ { user_id: '2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5',
name: 'wuwanyu',
psw: '123',
school: 'Northeastern university',
major: 'Communication engineering',
points: '10',
datems: '1450514441486',
createdAt: '2015-12-19T08:42:31.000Z',
updatedAt: '2015-12-19T08:42:31.000Z',
ID: 3,
phone: 2147483647 } ]
>> user.name: wuwanyu
Hi try this 100% works:
results=JSON.parse(JSON.stringify(results))
doStuffwithTheResult(results);
You can copy all enumerable own properties of an object to a new one by Object.assign(target, ...sources):
trivial_object = Object.assign({}, non_trivial_object);
so in your scenario, it should be enough to change
ret.push(i);
to
ret.push(Object.assign({}, i));
you try the code which gives JSON without rowdatapacket:
var ret = [];
conn.query(SQLquery, function(err, rows, fields) {
if (err)
alert("...");
else {
ret = JSON.stringify(rows);
}
doStuffwithTheResult(ret);
}
going off of jan's answer of shallow-copying the object, another clean implementation using map function,
High level of what this solution does: iterate through all the rows and copy the rows as valid js objects.
// function will be used on every row returned by the query
const objectifyRawPacket = row => ({...row});
// iterate over all items and convert the raw packet row -> js object
const convertedResponse = results.map(objectifyRawPacket);
We leveraged the array map function: it will go over every item in the array, use the item as input to the function, and insert the output of the function into the array you're assigning.
more specifically on the objectifyRawPacket function: each time it's called its seeing the "{ RawDataPacket }" from the source array. These objects act a lot like normal objects - the "..." (spread) operator copies items from the array after the periods - essentially copying the items into the object it's being called in.
The parens around the spread operator on the function are necessary to implicitly return an object from an arrow function.
Solution
Just do: JSON.stringify(results)
I found an easy way
Object.prototype.parseSqlResult = function () {
return JSON.parse(JSON.stringify(this[0]))
}
At db layer do the parsing as
let users= await util.knex.raw('select * from user')
return users.parseSqlResult()
This will return elements as normal JSON array.
If anybody needs to retrive specific RowDataPacket object from multiple queries, here it is.
Before you start
Important: Ensure you enable multipleStatements in your mysql connection like so:
// Connection to MySQL
var db = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '123',
database: 'TEST',
multipleStatements: true
});
Multiple Queries
Let's say we have multiple queries running:
// All Queries are here
const lastCheckedQuery = `
-- Query 1
SELECT * FROM table1
;
-- Query 2
SELECT * FROM table2;
`
;
// Run the query
db.query(lastCheckedQuery, (error, result) => {
if(error) {
// Show error
return res.status(500).send("Unexpected database error");
}
If we console.log(result) you'll get such output:
[
[
RowDataPacket {
id: 1,
ColumnFromTable1: 'a',
}
],
[
RowDataPacket {
id: 1,
ColumnFromTable2: 'b',
}
]
]
Both results show for both tables.
Here is where basic Javascript array's come in place https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
To get data from table1 and column named ColumnFromTable1 we do
result[0][0].ColumnFromTable1 // Notice the double [0]
which gives us result of a.
db.query('select * from login',(err, results, fields)=>{
if(err){
console.log('error in fetching data')
}
var string=JSON.stringify(results);
console.log(string);
var json = JSON.parse(string);
// to get one value here is the option
console.log(json[0].name);
})
conn.query(sql, (err,res,fields) => {
let rawData = res;
let dataNormalized = {...rawData[0]};
})
//Object Destructuring
This worked for me hope it helps you.
I think it is simplest way to copy object.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
Simpler way:
.then( resp=> {
let resultFromDb= Object.values(resp)[0]
console.log(resultFromDb)
}
In my example I received an object in response.
When I use Object.values I have the value of the property as a response, however it comes inside an array, using [0] access the first index of this array, now i have the value to use it where I need it.
I had this problem when trying to consume a value returned from a stored procedure.
console.log(result[0]);
would output "[ RowDataPacket { datetime: '2019-11-15 16:37:05' } ]".
I found that
console.log(results[0][0].datetime);
Gave me the value I wanted.
I had a similar problem and the solution was as follows:
const results = pool.query('sql sentence',[params]);
console.log((results[0])[0].name);
How to ACCESS what you get back from the database, this works for me:
async function getPageId(pageSlug){
let sql_update = 'SELECT id FROM pages WHERE pageSlug = ?';
let arrValues = [
pageSlug
];
let result = await mydb.query(sql_update, arrValues);
let r = JSON.parse(JSON.stringify(result));
if(r?.length){
return r[0].id;
}else{
return false;
}
}
I really don't see what is the big deal with this I mean look if a run my sp which is CALL ps_get_roles();.
Yes I get back an ugly ass response from DB and stuff. Which is this one:
[
[
RowDataPacket {
id: 1,
role: 'Admin',
created_at: '2019-12-19 16:03:46'
},
RowDataPacket {
id: 2,
role: 'Recruiter',
created_at: '2019-12-19 16:03:46'
},
RowDataPacket {
id: 3,
role: 'Regular',
created_at: '2019-12-19 16:03:46'
}
],
OkPacket {
fieldCount: 0,
affectedRows: 0,
insertId: 0,
serverStatus: 35,
warningCount: 0,
message: '',
protocol41: true,
changedRows: 0
}
]
it is an array that kind of look like this:
rows[0] = [
RowDataPacket {/* them table rows*/ },
RowDataPacket { },
RowDataPacket { }
];
rows[1] = OkPacket {
/* them props */
}
but if I do an http response to index [0] of rows at the client I get:
[
{"id":1,"role":"Admin","created_at":"2019-12-19 16:03:46"},
{"id":2,"role":"Recruiter","created_at":"2019-12-19 16:03:46"},
{"id":3,"role":"Regular","created_at":"2019-12-19 16:03:46"}
]
and I didnt have to do none of yow things
rows[0].map(row => {
return console.log("row: ", {...row});
});
the output gets some like this:
row: { id: 1, role: 'Admin', created_at: '2019-12-19 16:03:46' }
row: { id: 2, role: 'Recruiter', created_at: '2019-12-19 16:03:46' }
row: { id: 3, role: 'Regular', created_at: '2019-12-19 16:03:46' }
So you all is tripping for no reason. Or it also could be the fact that I'm running store procedures instead of regular querys, the response from query and sp is not the same.
Im trying to get more than one object from In Memory Data service and i cant manage to do that, just wondering if it is even possible to get? or i just can have one testing data without possibility to extend it it looks like that:
import { InMemoryDbService } from 'angular-in-memory-web-api';
export class InMemoryDataService implements InMemoryDbService {
createDb() {
const groups = [
{id: 0, name: 'Mr. Nice'},
{id: 12, name: 'Narco'},
{id: 13, name: 'Bombasto'},
{id: 14, name: 'Celeritas'},
{id: 15, name: 'Magneta'},
{id: 16, name: 'RubberMan'},
{id: 17, name: 'Dynama'},
{id: 18, name: 'Dr IQ'},
{id: 19, name: 'Magma'},
{id: 20, name: 'Tornado'},
];
return {groups}
}
}
If you want to get the whole array from the InMemoryDbService you need to send a http get request to the address: 'api/groups'.
In case you want only a specific object returned from the list you need to send a http get request to the address: 'api/groups/id' where id is one of the numbers defined in your groups const.
In case you meant to add another collection to the InMemoryDbService, you can just define a new const array and then add it to the return part of the createDb method like this:
const itemList = [
{id: 1, name: "First item"},
{id: 2, name: "Second item"},
];
return {
groups: groups,
items: itemList
}
Note that the endpoints now are: 'api/groups', 'api/groups/id', 'api/items' and 'api/items/id' where id is one of the numbers defined in your const arrays.
You also need to register the InMemoryWebApiModule in the imports array of your app.module.ts:
imports: [
InMemoryWebApiModule.forRoot(InMemoryDbService)
],
I want to replace the value in existing JSON object in Node.js
Code :
var designationName='Softwar Engineer';
console.log(generateData[0]);
Console Output:
{
email: 'xxxxxx#gmail.com',
designation: 10,
id: 274,
first_name: 'firstname',
mobile: '1234567890',
last_name: 'lastname'
}
In the above console output 'designation' value printed as '10'
Expected Result:
I want to replace "designation: Software Engineer" instead of "designation:10"
Considering generateData[0] contains the following json which you fetch from a database
{
email: 'xxxxxx#gmail.com',
designation: 10,
id: 274,
first_name: 'firstname',
mobile: '1234567890',
last_name: 'lastname'
};
To replace "designation: Software Engineer" instead of "designation:10"
var designationName = 'Software Engineer';
if(generateData[0]){
generateData[0]['designation']= designationName;
}
console.log(generateData[0]);
var designationName='Softwar Engineer';
if( generateData.length && generateData[0].designation)
{
generateData[0].designation = designationName;
}
console.log(generateData[0]);
I'm currently developing a desktop application with Node-webkit. During that process I need to get some data from a local MySQL-database.
The querying works fine, but I can't figure out how to access the results. I store all of them in an array that is then passed to a function. In the console they look like this:
RowDataPacket {user_id: 101, ActionsPerformed: 20}
RowDataPacket {user_id: 102, ActionsPerformed: 110}
RowDataPacket {user_id: 104, ActionsPerformed: 3}
And here is the query structure:
var ret = [];
conn.query(SQLquery, function(err, rows, fields) {
if (err)
alert("...");
else {
for (var i of rows)
ret.push(i);
}
doStuffwithTheResult(ret);
}
How do I retrieve this in the doStuffwithTheResult function? The values are more important, but if I could get the keys as well that would be great.
Turns out they are normal objects and you can access them through user_id.
RowDataPacket is actually the name of the constructor function that creates an object, it would look like this new RowDataPacket(user_id, ...). You can check by accessing its name [0].constructor.name
If the result is an array, you would have to use [0].user_id.
With Object.prototype approach, JSON.parse(JSON.stringify(rows)) returns object, extract values with Object.values()
let result = Object.values(JSON.parse(JSON.stringify(rows)));
Usage:
result.forEach((v) => console.log(v));
I also met the same problem recently, when I use waterline in express project for complex queries ,use the SQL statement to query.
this is my solution: first transform the return value(RowDataPacket object) into string, and then convert this string into the json object.
The following is code :
//select all user (查询全部用户)
find: function(req, res, next){
console.log("i am in user find list");
var sql="select * from tb_user";
req.models.tb_user.query(sql,function(err, results) {
console.log('>> results: ', results );
var string=JSON.stringify(results);
console.log('>> string: ', string );
var json = JSON.parse(string);
console.log('>> json: ', json);
console.log('>> user.name: ', json[0].name);
req.list = json;
next();
});
}
The following is console:
>> results: [ RowDataPacket {
user_id: '2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5',
name: 'wuwanyu',
psw: '123',
school: 'Northeastern university',
major: 'Communication engineering',
points: '10',
datems: '1450514441486',
createdAt: Sat Dec 19 2015 16:42:31 GMT+0800 (中国标准时间),
updatedAt: Sat Dec 19 2015 16:42:31 GMT+0800 (中国标准时间),
ID: 3,
phone: 2147483647 } ]
>> string: [{"user_id":"2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5","name":"wuwanyu","psw":"123","school":"Northeastern university","major":"Communication engineering","points":"10","datems":"1450514
441486","createdAt":"2015-12-19T08:42:31.000Z","updatedAt":"2015-12-19T08:42:31.000Z","ID":3,"phone":2147483647}]
>> json: [ { user_id: '2fc48bd0-a62c-11e5-9a32-a31e4e4cd6a5',
name: 'wuwanyu',
psw: '123',
school: 'Northeastern university',
major: 'Communication engineering',
points: '10',
datems: '1450514441486',
createdAt: '2015-12-19T08:42:31.000Z',
updatedAt: '2015-12-19T08:42:31.000Z',
ID: 3,
phone: 2147483647 } ]
>> user.name: wuwanyu
Hi try this 100% works:
results=JSON.parse(JSON.stringify(results))
doStuffwithTheResult(results);
You can copy all enumerable own properties of an object to a new one by Object.assign(target, ...sources):
trivial_object = Object.assign({}, non_trivial_object);
so in your scenario, it should be enough to change
ret.push(i);
to
ret.push(Object.assign({}, i));
you try the code which gives JSON without rowdatapacket:
var ret = [];
conn.query(SQLquery, function(err, rows, fields) {
if (err)
alert("...");
else {
ret = JSON.stringify(rows);
}
doStuffwithTheResult(ret);
}
going off of jan's answer of shallow-copying the object, another clean implementation using map function,
High level of what this solution does: iterate through all the rows and copy the rows as valid js objects.
// function will be used on every row returned by the query
const objectifyRawPacket = row => ({...row});
// iterate over all items and convert the raw packet row -> js object
const convertedResponse = results.map(objectifyRawPacket);
We leveraged the array map function: it will go over every item in the array, use the item as input to the function, and insert the output of the function into the array you're assigning.
more specifically on the objectifyRawPacket function: each time it's called its seeing the "{ RawDataPacket }" from the source array. These objects act a lot like normal objects - the "..." (spread) operator copies items from the array after the periods - essentially copying the items into the object it's being called in.
The parens around the spread operator on the function are necessary to implicitly return an object from an arrow function.
Solution
Just do: JSON.stringify(results)
I found an easy way
Object.prototype.parseSqlResult = function () {
return JSON.parse(JSON.stringify(this[0]))
}
At db layer do the parsing as
let users= await util.knex.raw('select * from user')
return users.parseSqlResult()
This will return elements as normal JSON array.
If anybody needs to retrive specific RowDataPacket object from multiple queries, here it is.
Before you start
Important: Ensure you enable multipleStatements in your mysql connection like so:
// Connection to MySQL
var db = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '123',
database: 'TEST',
multipleStatements: true
});
Multiple Queries
Let's say we have multiple queries running:
// All Queries are here
const lastCheckedQuery = `
-- Query 1
SELECT * FROM table1
;
-- Query 2
SELECT * FROM table2;
`
;
// Run the query
db.query(lastCheckedQuery, (error, result) => {
if(error) {
// Show error
return res.status(500).send("Unexpected database error");
}
If we console.log(result) you'll get such output:
[
[
RowDataPacket {
id: 1,
ColumnFromTable1: 'a',
}
],
[
RowDataPacket {
id: 1,
ColumnFromTable2: 'b',
}
]
]
Both results show for both tables.
Here is where basic Javascript array's come in place https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
To get data from table1 and column named ColumnFromTable1 we do
result[0][0].ColumnFromTable1 // Notice the double [0]
which gives us result of a.
db.query('select * from login',(err, results, fields)=>{
if(err){
console.log('error in fetching data')
}
var string=JSON.stringify(results);
console.log(string);
var json = JSON.parse(string);
// to get one value here is the option
console.log(json[0].name);
})
conn.query(sql, (err,res,fields) => {
let rawData = res;
let dataNormalized = {...rawData[0]};
})
//Object Destructuring
This worked for me hope it helps you.
I think it is simplest way to copy object.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
Simpler way:
.then( resp=> {
let resultFromDb= Object.values(resp)[0]
console.log(resultFromDb)
}
In my example I received an object in response.
When I use Object.values I have the value of the property as a response, however it comes inside an array, using [0] access the first index of this array, now i have the value to use it where I need it.
I had this problem when trying to consume a value returned from a stored procedure.
console.log(result[0]);
would output "[ RowDataPacket { datetime: '2019-11-15 16:37:05' } ]".
I found that
console.log(results[0][0].datetime);
Gave me the value I wanted.
I had a similar problem and the solution was as follows:
const results = pool.query('sql sentence',[params]);
console.log((results[0])[0].name);
How to ACCESS what you get back from the database, this works for me:
async function getPageId(pageSlug){
let sql_update = 'SELECT id FROM pages WHERE pageSlug = ?';
let arrValues = [
pageSlug
];
let result = await mydb.query(sql_update, arrValues);
let r = JSON.parse(JSON.stringify(result));
if(r?.length){
return r[0].id;
}else{
return false;
}
}
I really don't see what is the big deal with this I mean look if a run my sp which is CALL ps_get_roles();.
Yes I get back an ugly ass response from DB and stuff. Which is this one:
[
[
RowDataPacket {
id: 1,
role: 'Admin',
created_at: '2019-12-19 16:03:46'
},
RowDataPacket {
id: 2,
role: 'Recruiter',
created_at: '2019-12-19 16:03:46'
},
RowDataPacket {
id: 3,
role: 'Regular',
created_at: '2019-12-19 16:03:46'
}
],
OkPacket {
fieldCount: 0,
affectedRows: 0,
insertId: 0,
serverStatus: 35,
warningCount: 0,
message: '',
protocol41: true,
changedRows: 0
}
]
it is an array that kind of look like this:
rows[0] = [
RowDataPacket {/* them table rows*/ },
RowDataPacket { },
RowDataPacket { }
];
rows[1] = OkPacket {
/* them props */
}
but if I do an http response to index [0] of rows at the client I get:
[
{"id":1,"role":"Admin","created_at":"2019-12-19 16:03:46"},
{"id":2,"role":"Recruiter","created_at":"2019-12-19 16:03:46"},
{"id":3,"role":"Regular","created_at":"2019-12-19 16:03:46"}
]
and I didnt have to do none of yow things
rows[0].map(row => {
return console.log("row: ", {...row});
});
the output gets some like this:
row: { id: 1, role: 'Admin', created_at: '2019-12-19 16:03:46' }
row: { id: 2, role: 'Recruiter', created_at: '2019-12-19 16:03:46' }
row: { id: 3, role: 'Regular', created_at: '2019-12-19 16:03:46' }
So you all is tripping for no reason. Or it also could be the fact that I'm running store procedures instead of regular querys, the response from query and sp is not the same.
Given the following RelationalModel model:
var Server = Backbone.RelationalModel.extend({
relations: [{
type: Backbone.HasMany,
key: 'databases',
relatedModel: 'Database',
collectionType: 'DatabaseCollection',
includeInJSON: 'id'
}],
defaults: {
databases: []
},
});
var Database = Backbone.RelationalModel.extend({});
var DatabaseCollection = Backbone.Collection.extend({
model: Database
});
And these objects:
new Database({
id: 1,
name: 'DB1'
});
new Database({
id: 2,
name: 'DB2'
});
var s1 = new Server({
id: 3,
name: 'S1',
databases: [1,2]
});
What would be the easiest/recommended way to serialize/deserialize this model to something aproaching this JSON structure?:
{
databases: [
{ id: 1, name: 'DB1' }
{ id: 2, name: 'DB2' }
],
servers: [
{ id: 3, name: 'S1', databases: [1, 2] }
]
}
Such that the data can be sent to / read from the server in a single request.
Thanks!
Tim
I was able to produce the JSON you described using your example with some minor changes in this fiddle I just created Example.
I made these changes due to some warnings that were being shown in the debugger and to get the result you described. Hope this helps.
Moved the declaration of Database Model and DatabaseCollection to top before Server since Servers relatedModel and CollectionType point to those Models.
For relatedModel and collectionType instead of using Strings used the reference to Database and DatabaseCollection
Created a collection for Servers called ServerCollection
Added a few more examples
Here is the code you end up with, I just created a plain old Backbone model to combine the two collection into one. Calling toJSON gives you the single JSON object to transmit to the server.
var Database = Backbone.RelationalModel.extend({});
var DatabaseCollection = Backbone.Collection.extend({
model: Database
});
var Server = Backbone.RelationalModel.extend({
relations: [{
type: Backbone.HasMany,
key: 'databases',
relatedModel: Database,
collectionType: DatabaseCollection,
includeInJSON: 'id'
}],
defaults: {
databases: []
}
});
var ServerCollection = Backbone.Collection.extend({
model: Server
});
var allDatabases = new DatabaseCollection();
allDatabases.add([
new Database({ id: 1, name: 'DB1' }),
new Database({ id: 2, name: 'DB2' }),
new Database({ id: 3, name: 'DB3' }),
new Database({ id: 4, name: 'DB4' })
]);
var allServers = new ServerCollection();
allServers.add([
new Server({
id: 30,
name: 'S1',
databases: [
allDatabases.get(1),
allDatabases.get(2)
]
}),
new Server({
id: 40,
name: 'S2',
databases: [
allDatabases.get(3),
allDatabases.get(4)
]
})
]);
// combine into an object to transfer to server as one
var serverObject = new Backbone.Model({
'servers': allServers,
'databases': allDatabases
});
console.log(serverObject.toJSON());