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array data insertion in mysql and prevent duplicate in node js [duplicate]

I've searched around but didn't find if it's possible.
I've this MySQL query:
INSERT INTO table (id,a,b,c,d,e,f,g) VALUES (1,2,3,4,5,6,7,8)
Field id has a "unique index", so there can't be two of them. Now if the same id is already present in the database, I'd like to update it. But do I really have to specify all these field again, like:
INSERT INTO table (id,a,b,c,d,e,f,g) VALUES (1,2,3,4,5,6,7,8)
ON DUPLICATE KEY UPDATE a=2,b=3,c=4,d=5,e=6,f=7,g=8
Or:
INSERT INTO table (id,a,b,c,d,e,f,g) VALUES (1,2,3,4,5,6,7,8)
ON DUPLICATE KEY UPDATE a=VALUES(a),b=VALUES(b),c=VALUES(c),d=VALUES(d),e=VALUES(e),f=VALUES(f),g=VALUES(g)
I've specified everything already in the insert...
A extra note, I'd like to use the work around to get the ID to!
id=LAST_INSERT_ID(id)
I hope somebody can tell me what the most efficient way is.

The UPDATE statement is given so that older fields can be updated to new value. If your older values are the same as your new ones, why would you need to update it in any case?
For eg. if your columns a to g are already set as 2 to 8; there would be no need to re-update it.
Alternatively, you can use:
INSERT INTO table (id,a,b,c,d,e,f,g)
VALUES (1,2,3,4,5,6,7,8)
ON DUPLICATE KEY
UPDATE a=a, b=b, c=c, d=d, e=e, f=f, g=g;
To get the id from LAST_INSERT_ID; you need to specify the backend app you're using for the same.
For LuaSQL, a conn:getlastautoid() fetches the value.

There is a MySQL specific extension to SQL that may be what you want - REPLACE INTO
However it does not work quite the same as 'ON DUPLICATE UPDATE'
It deletes the old row that clashes with the new row and then inserts the new row. So long as you don't have a primary key on the table that would be fine, but if you do, then if any other table references that primary key
You can't reference the values in the old rows so you can't do an equivalent of
INSERT INTO mytable (id, a, b, c) values ( 1, 2, 3, 4)
ON DUPLICATE KEY UPDATE
id=1, a=2, b=3, c=c + 1;
I'd like to use the work around to get the ID to!
That should work — last_insert_id() should have the correct value so long as your primary key is auto-incrementing.
However as I said, if you actually use that primary key in other tables, REPLACE INTO probably won't be acceptable to you, as it deletes the old row that clashed via the unique key.
Someone else suggested before you can reduce some typing by doing:
INSERT INTO `tableName` (`a`,`b`,`c`) VALUES (1,2,3)
ON DUPLICATE KEY UPDATE `a`=VALUES(`a`), `b`=VALUES(`b`), `c`=VALUES(`c`);

There is no other way, I have to specify everything twice. First for the insert, second in the update case.

Here is a solution to your problem:
I've tried to solve problem like yours & I want to suggest to test from simple aspect.
Follow these steps: Learn from simple solution.
Step 1: Create a table schema using this SQL Query:
CREATE TABLE IF NOT EXISTS `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(30) NOT NULL,
`password` varchar(32) NOT NULL,
`status` tinyint(1) DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `no_duplicate` (`username`,`password`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;
Step 2: Create an index of two columns to prevent duplicate data using following SQL Query:
ALTER TABLE `user` ADD INDEX no_duplicate (`username`, `password`);
or, Create an index of two column from GUI as follows:
Step 3: Update if exist, insert if not using following queries:
INSERT INTO `user`(`username`, `password`) VALUES ('ersks','Nepal') ON DUPLICATE KEY UPDATE `username`='master',`password`='Nepal';
INSERT INTO `user`(`username`, `password`) VALUES ('master','Nepal') ON DUPLICATE KEY UPDATE `username`='ersks',`password`='Nepal';

Just in case you are able to utilize a scripting language to prepare your SQL queries, you could reuse field=value pairs by using SET instead of (a,b,c) VALUES(a,b,c).
An example with PHP:
$pairs = "a=$a,b=$b,c=$c";
$query = "INSERT INTO $table SET $pairs ON DUPLICATE KEY UPDATE $pairs";
Example table:
CREATE TABLE IF NOT EXISTS `tester` (
`a` int(11) NOT NULL,
`b` varchar(50) NOT NULL,
`c` text NOT NULL,
UNIQUE KEY `a` (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

I know it's late, but i hope someone will be helped of this answer
INSERT INTO t1 (a,b,c) VALUES (1,2,3),(4,5,6)
ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);
You can read the tutorial below here :
https://mariadb.com/kb/en/library/insert-on-duplicate-key-update/
http://www.mysqltutorial.org/mysql-insert-or-update-on-duplicate-key-update/

You may want to consider using REPLACE INTO syntax, but be warned, upon duplicate PRIMARY / UNIQUE key, it DELETES the row and INSERTS a new one.
You won't need to re-specify all the fields. However, you should consider the possible performance reduction (depends on your table design).
Caveats:
If you have AUTO_INCREMENT primary key, it will be given a new one
Indexes will probably need to be updated

With MySQL v8.0.19 and above you can do this:
mysql doc
INSERT INTO mytable(fielda, fieldb, fieldc)
VALUES("2022-01-01", 97, "hello")
AS NEW(newfielda, newfieldb, newfieldc)
ON DUPLICATE KEY UPDATE
fielda=newfielda,
fieldb=newfieldb,
fieldc=newfieldc;
SIDENOTE: Also if you want a conditional in the on duplicate key update part there is a twist in MySQL. If you update fielda as the first argument and include it inside the IF clause for fieldb it will already be updated to the new value! Move it to the end or alike. Let's say fielda is a date like in the example and you want to update only if the date is newer than the previous:
INSERT INTO mytable(fielda, fieldb)
VALUES("2022-01-01", 97)
AS NEW(newfielda, newfieldb, newfieldc)
ON DUPLICATE KEY UPDATE
fielda=IF(fielda<STR_TO_DATE(newfielda,'%Y-%m-%d %H:%i:%s'),newfielda,fielda),
fieldb=IF(fielda<STR_TO_DATE(newfielda,'%Y-%m-%d %H:%i:%s'),newfieldb,fieldb);
in this case fieldb would never be updated because of the <! you need to move the update of fielda below it or check with <= or =...!
INSERT INTO mytable(fielda, fieldb)
VALUES("2022-01-01", 97)
AS NEW(newfielda, newfieldb, newfieldc)
ON DUPLICATE KEY UPDATE
fielda=IF(fielda<STR_TO_DATE(newfielda,'%Y-%m-%d %H:%i:%s'),newfielda,fielda),
fieldb=IF(fielda=STR_TO_DATE(newfielda,'%Y-%m-%d %H:%i:%s'),newfieldb,fieldb);
This works as expected with using = since fielda is already updated to its new value before reaching the if clause of fieldb... Personally i like <= the most in such a case if you ever rearrange the statement...

you can use insert ignore for such case, it will ignore if it gets duplicate records
INSERT IGNORE
... ; -- without ON DUPLICATE KEY

React how to address a key from string name

Ok, so I have a database with data sets in it. the application performs a base API call to retrieve that base data set containing all other data sets. I will receive a string variable with the name of the key I need to access so let's say const addon = "Book". However, I don't know the key name beforehand. So the following code works but I need to somehow not hard code the key parameter but rather use the string value incoming from the const addon. I am not quite sure how to do this please point me to the right documentation or explain how to achieve the wanted result.
const columns = levelOne.Book && Object.keys(levelOne.Book);
However, as the incoming param might not be "Book" but anything else it will only work for this case. It is guaranteed that there is a key-value pair where the key bears the name stored in the string value of addon.

You can use a variable as the key. For example, levelOne[variable] where variable is the string that you want to use as the key.
Also, you can get the keys through Object.keys(levelOne) and then you can set variable value from the keys array.

Access element of dictionary in pug/jade

If I have a dictionary like:
x = {"A" : 1, "B" : 2 }
And I pass this dictionary into the pug file, how can I access a specific key value without iterating through all the elements in the dictionary?
For ex. x[A]
The only way I can think of right now is to iterate through the elements:
for key, val in x
And then have an if conditional in there that displays val when key equals A.
Am I missing something obvious here?

If you passes x dictionary to your .pug file you can simply show the key 1 of this dictionary using ${x.A}, same as in normal javascript.
Be sure to add back-tick between the expression.

every Javascript object is an associative array which is the most general sort of array you can invent - sometimes this is called a hash or map structure or a dictionary object.
An associative array is simply a set of key value pairs.
The value is stored in association with its key and if you provide the key the array will return the value.
This is all an associative array is and the name comes from the association between the key and the value. The key is a sort of generalized address that can be used to retrieve the stored value.
For example:
array={key1: 'value1',key2:'value2'};
creates an object called array with two keys and two values which in this case happen to be two constant strings.
Notice that the value stored can be any JavaScript object and in this example it is probably better to think of storing two string objects rather two string literals.
The key can be either an identifier, a string or a number but more about the difference in the key type as we progress.
You can retrieve a value via it key using array notation:
console.log(array['key2']);
Which displays the string value2. If you try and access a key that doesn't exist then you get the result undefined.
As the associative array is used to as the basis of the JavaScript object there is an alternative way to access a value that makes the key look like a property. That is you can access the value using "property syntax" as in:
console.log(array.key2);
So in jade/pug if you pass the x it will show you the similar result like in js. In your case it would be something like that:
${x["A"]} or ${x.A}

How can I get the key as well as the value when using db.js to query IndexedDB?

I have an IndexedDB of changes. I add an item like this, and then log the result to check the key has been created successfully:
_this._idb.add('steps', step).done(function (items) {
var item = items[0];
_logger.log("ADDED STEP", { id: item.__id__, step: item }, "CT");
});
The output from this is as expected:
...as you can see, the id has been added to the object when it is stored.
However, when I query the db to getback a list of objects, using this code:
this._idb.steps.query('timestamp').bound(start, end).execute().done(function (results) {
_logger.log("Results", results, "CT");
}
I don't get the id as part of the object that is returned:
... and the lack of id makes updating and deleting impossible.
How can I get the id of the item when I query indexed db using db.js - or am I approaching this in the wrong way, and is there something else I should be doing?
(Note: I'm using TypeScript to compile the JS, but I don't think that's especially relevant to this question)

This is expected behaviour, you're only going to get the __id__ property if you don't define a keyPath in your db schema.
Because there's no keyPath defined the value is not associated with it in indexeddb, it's only added to the resulting object after it has been added, because at that point in time we know the auto-incremented value that IndexedDB has assigned to it.
Since the value isn't really part of the object I don't have any way to assign it to the object when it comes out during a query, maybe I could use the position in the array but that's more likely to be wrong than right.
If you want the ID to be persisted against the object then you need to define a keyPath as part of the object store schema and the property will be added to the resulting object and available and it will be on the object returned from a query.
Disclaimer - I wrote db.js

Looking at the source, __id__ is only defined when your keyPath is null in the add() method. From what I'm seeing, you'll never see this in a query() response.
In IDB null keyPaths are allowed only when using auto-incrementing ("out-of-line") keys. So if you're getting the object back, it should have an auto-incrementing key on it or some other keyPath.
The __ prefix in JavaScript usually means the developer intended it to be a "private" property. I'm guessing this is for internal use and you shouldn't be counting on this in your application code.
Consider using explicit, so-called "in-line" keys on your object store.

The goal of db.js is easy and simple to use. Your is advanced use case.

Store information in object, sort by key + search object later

I'm having a hard time figuring out this.
So, I am making a site where I need to store the horizontal position of elements in a object with the ID as value. Then I need to sort the object by the key. Later I have to loop though the object and find the closest elements (both before and after).
I am struggling with storing the information. I have it like a variabel.
Is it correct to store it like this:
myObj.x = tempId;
Next, how do I sort the keys? It should sort as a number, not text because I had problem with the sort doing 14, 1500, 800.
And last, how can I loop the object and maintain access to both key and value? If I do for (var i in obj) I loose the key-value.