Risk of losing LAST_INSERT_ID() with transactions [duplicate] - mysql

This question already has an answer here:
Is LAST_INSERT_ID() in a transaction dependable?
(1 answer)
Closed 5 years ago.
When using transactions for the code below, is there any risk of the LAST_INSERT_ID() not belonging to the first insert? That is, is it possible for another insert action to take place, say from different user interactions like INSERT INTO comments (comment) VALUES ('kthanksbuy');, which would then give LAST_INSERT_ID() the comments ID instead of the user's ID?
BEGIN;
INSERT INTO users (username, password)
VALUES('john', 'pass');
INSERT INTO profiles (userid, bio, homepage)
VALUES(LAST_INSERT_ID(),'I am a lumberjack, and I am ok!', 'http://www.stackoverflow.com');
COMMIT;
Thanks.

LAST_INSERT_ID() - Value of the AUTOINCREMENT column for the last INSERT.
Or more broad: LAST_INSERT_ID() returns a BIGINT UNSIGNED (64-bit) value representing the first automatically generated value successfully inserted for an AUTO_INCREMENT column as a result of the most recently executed INSERT statement. It is from official documentation.
And it is definitely not first insert...

Related

insert many rows, LAST_INSERT_ID return 1 [duplicate]

This question already has answers here:
MySQL LAST_INSERT_ID() used with multiple records INSERT statement
(3 answers)
Closed 3 years ago.
Have:
1. create DB
2. create Table
3. insert 3 rows
4. select LAST_INSERT_ID()
Here test code:
DROP DATABASE IF EXISTS TEST;
CREATE DATABASE TEST;
USE TEST;
CREATE TABLE test (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
age INT
);
INSERT INTO test (age) VALUES (1), (2), (3);
SELECT LAST_INSERT_ID();
Why LAST_INSERT_ID() return 1 ?
Excepted: 3
How to get valid LAST_INSERT_ID() ?
The MySQL documentation clearly explains this behavior:
With no argument, LAST_INSERT_ID() returns a BIGINT UNSIGNED (64-bit) value representing the first (emphasis mine) automatically generated value successfully inserted for an AUTO_INCREMENT column as a result of the most recently executed INSERT statement. The value of LAST_INSERT_ID() remains unchanged if no rows are successfully inserted.
The first value generated by the auto increment sequence in the insert was 1, not 2 or 3, so the value 1 gets returned.
I think the confusion you have is around the name LAST_INSERT_ID. The "last" part refers to the most recent insert statement, not the most recent id value within that insert.

MySQL Insert, how to get incremental id from insert [duplicate]

This question already has answers here:
Get the new record primary key ID from MySQL insert query?
(13 answers)
Closed 3 years ago.
INSERT INTO db.a (a,b,c,d,e,f,g,h,i)
VALUES (2,2,"a",'b','c','d',1,'e',0)
The first insert will insert a new row with a incremental_id. I need to take that incremental_id and make an entry into db.b using that incremental_id, for example, if it was 6005 I would make the following insert.
INSERT INTO db.b
(a_id, s_id, use_i)
VALUES (6005,7,0)
How can I automatically grab the id of the first insert so my second insert can be built dynamically after the first query?
You can use function LAST_INSERT_ID() which will return exactly what you need.

Mysql use last inserted id in a different table query multiple times [duplicate]

This question already has answers here:
LAST_INSERT_ID() MySQL
(14 answers)
Closed 5 years ago.
I am working on a query that I'd like to run to import some phrases based on actions.
These are the two tables I want to insert data into.
actions:
- id
- name
- data
phrases:
- id
- action_id
- phrase
Where phrases.action_id = actions.id
I want to create a new action. Return that ID and then add multiple phrases using the returned ID.
Is there anyway of making the action.id that was inserted persistent or a variable for re-use.
My train of thinking has led me to things like:
SELECT LAST_INSERT_ID();
And
OUTPUT insterted.id
Not expecting an answer but some helpful information that will point me in the right direction would be great
You can assign it to a user variable:
INSERT INTO actions ...;
SET #action_id = LAST_INSERT_ID();
Then you can use #action_id in all the INSERT queries that insert into phrases.
INSERT INTO phrases (action_id, phrase) VALUES (#action_id, "Whatever");
INSERT INTO phrases (action_id, phrase) VALUES (#action_id, "Some other phrase");
You could also solve it by doing all the inserts in a single query:
INSERT INTO phrases (action_id, phrase) VALUES
(LAST_INSERT_ID(), "Whatever"),
(LAST_INSERT_ID(), "Some other phrase");

MySQL Insert into multiple tables? (Database normalization?) [duplicate]

This question already has answers here:
Insert into multiple tables in one query
(6 answers)
Closed 1 year ago.
I tried searching a way to insert information in multiple tables in the same query, but found out it's impossible?
So I want to insert it by simply using multiple queries i.e;
INSERT INTO users (username, password) VALUES('test', 'test')
INSERT INTO profiles (userid, bio, homepage) VALUES('[id of the user here?]','Hello world!', 'http://www.stackoverflow.com')
But how can I give the auto-increment id from the users to the "manual" userid for the profile table?
No, you can't insert into multiple tables in one MySQL command. You can however use transactions.
BEGIN;
INSERT INTO users (username, password)
VALUES('test', 'test');
INSERT INTO profiles (userid, bio, homepage)
VALUES(LAST_INSERT_ID(),'Hello world!', 'http://www.stackoverflow.com');
COMMIT;
Have a look at LAST_INSERT_ID() to reuse autoincrement values.
You said "After all this time trying to figure it out, it still doesn't work. Can't I simply put the just generated ID in a $var and put that $var in all the MySQL commands?"
Let me elaborate: there are 3 possible ways here:
In the code you see above. This
does it all in MySQL, and the
LAST_INSERT_ID() in the second
statement will automatically be the
value of the autoincrement-column
that was inserted in the first
statement.
Unfortunately, when the second statement itself inserts rows in a table with an auto-increment column, the LAST_INSERT_ID() will be updated to that of table 2, and not table 1. If you still need that of table 1 afterwards, we will have to store it in a variable. This leads us to ways 2 and 3:
Will stock the LAST_INSERT_ID() in
a MySQL variable:
INSERT ...
SELECT LAST_INSERT_ID() INTO #mysql_variable_here;
INSERT INTO table2 (#mysql_variable_here, ...);
INSERT INTO table3 (#mysql_variable_here, ...);
Will stock the LAST_INSERT_ID() in a
php variable (or any language that
can connect to a database, of your
choice):
INSERT ...
Use your language to retrieve the LAST_INSERT_ID(), either by executing that literal statement in MySQL, or using for example php's mysql_insert_id() which does that for you
INSERT [use your php variable here]
WARNING
Whatever way of solving this you choose, you must decide what should happen should the execution be interrupted between queries (for example, your database-server crashes). If you can live with "some have finished, others not", don't read on.
If however, you decide "either all queries finish, or none finish - I do not want rows in some tables but no matching rows in others, I always want my database tables to be consistent", you need to wrap all statements in a transaction. That's why I used the BEGIN and COMMIT here.
fairly simple if you use stored procedures:
call insert_user_and_profile('f00','http://www.f00.com');
full script:
drop table if exists users;
create table users
(
user_id int unsigned not null auto_increment primary key,
username varchar(32) unique not null
)
engine=innodb;
drop table if exists user_profile;
create table user_profile
(
profile_id int unsigned not null auto_increment primary key,
user_id int unsigned not null,
homepage varchar(255) not null,
key (user_id)
)
engine=innodb;
drop procedure if exists insert_user_and_profile;
delimiter #
create procedure insert_user_and_profile
(
in p_username varchar(32),
in p_homepage varchar(255)
)
begin
declare v_user_id int unsigned default 0;
insert into users (username) values (p_username);
set v_user_id = last_insert_id(); -- save the newly created user_id
insert into user_profile (user_id, homepage) values (v_user_id, p_homepage);
end#
delimiter ;
call insert_user_and_profile('f00','http://www.f00.com');
select * from users;
select * from user_profile;
What would happen, if you want to create many such records ones (to register 10 users, not just one)?
I find the following solution (just 5 queryes):
Step I: Create temporary table to store new data.
CREATE TEMPORARY TABLE tmp (id bigint(20) NOT NULL, ...)...;
Next, fill this table with values.
INSERT INTO tmp (username, password, bio, homepage) VALUES $ALL_VAL
Here, instead of $ALL_VAL you place list of values: ('test1','test1','bio1','home1'),...,('testn','testn','bion','homen')
Step II: Send data to 'user' table.
INSERT IGNORE INTO users (username, password)
SELECT username, password FROM tmp;
Here, "IGNORE" can be used, if you allow some users already to be inside. Optionaly you can use UPDATE similar to step III, before this step, to find whom users are already inside (and mark them in tmp table). Here we suppouse, that username is declared as PRIMARY in users table.
Step III: Apply update to read all users id from users to tmp table. THIS IS ESSENTIAL STEP.
UPDATE tmp JOIN users ON tmp.username=users.username SET tmp.id=users.id
Step IV: Create another table, useing read id for users
INSERT INTO profiles (userid, bio, homepage)
SELECT id, bio, homepage FROM tmp
have a look at mysql_insert_id()
here the documentation: http://in.php.net/manual/en/function.mysql-insert-id.php
try this
$sql= " INSERT INTO users (username, password) VALUES('test', 'test') ";
mysql_query($sql);
$user_id= mysql_insert_id();
if(!empty($user_id) {
$sql=INSERT INTO profiles (userid, bio, homepage) VALUES($user_id,'Hello world!', 'http://www.stackoverflow.com');
/* or
$sql=INSERT INTO profiles (userid, bio, homepage) VALUES(LAST_INSERT_ID(),'Hello world!', 'http://www.stackoverflow.com'); */
mysql_query($sql);
};
References
PHP
MYSQL
Just a remark about your saying
Hi, I tried searching a way to insert information in multiple tables in the same query
Do you eat all your lunch dishes mixed with drinks in the same bowl?
I suppose - no.
Same here.
There are things we do separately.
2 insert queries are 2 insert queries. It's all right. Nothing wrong with it. No need to mash it in one.
Same for select. A query must be sensible and do its job. That's the only reasons. Number of queries is not.
There is no point in looking for a way to stuff different queries in one call. Different calls is how the database API is meant to work.
For PDO You may do this
$dbh->beginTransaction();
$stmt1 = "INSERT INTO users (username, password) VALUES('test', 'test')";
$stmt2 = "INSERT INTO profiles (userid, bio, homepage) VALUES('LAST_INSERT_ID(),'Hello world!', 'http://www.stackoverflow.com')";
$sth1 = $dbh->prepare($stmt1);
$sth2 = $dbh->prepare($stmt2);
$sth1->execute (array ('test','test'));
$sth2->execute (array ('Hello world!','http://www.stackoverflow.com'));
$dbh->commit();

MySQL LAST_INSERT_ID() used with multiple records INSERT statement

If I insert multiple records with a loop that executes a single record insert, the last insert id returned is, as expected, the last one. But if I do a multiple records insert statement:
INSERT INTO people (name,age)
VALUES ('William',25), ('Bart',15), ('Mary',12);
Let's say the three above are the first records inserted in the table. After the insert statement I expected the last insert id to return 3, but it returned 1. The first insert id for the statement in question.
So can someone please confirm if this is the normal behavior of LAST_INSERT_ID() in the context of multiple records INSERT statements. So I can base my code on it.
Yes. This behavior of last_insert_id() is documented in the MySQL docs:
Important
If you insert multiple rows using a single INSERT statement, LAST_INSERT_ID() returns the value generated for the first inserted row only. The reason for this is to make it possible to reproduce easily the same INSERT statement against some other server.
This behavior is mentioned on the man page for MySQL. It's in the comments but is not challenged, so I'm guessing it's the expected behavior.
I think it's possible if your table has unique autoincrement column (ID) and you don't require them to be returned by mysql itself. I would cost you 3 more DB requests and some processing. It would require these steps:
Get "Before MAX(ID)" right before your insert:
SELECT MAX(id) AS before_max_id FROM table_name`
Make multiple INSERT ... VALUES () query with your data and keep them:
INSERT INTO table_name
(col1, col2)
VALUES
("value1-1" , "value1-2"),
("value2-1" , "value2-2"),
("value3-1" , "value3-2"),
ON DUPLICATE KEY UPDATE
Get "After MAX(ID)" right after your insert:
SELECT MAX(id) AS after_max_id FROM table_name`
Get records with IDs between "Before MAX(ID)" and "After MAX(ID)" including:
SELECT * FROM table_name WHERE id>$before_max_id AND id<=$after_max_id`
Do a check of retrieved data with data you inserted to match them and remove any records that were not inserted by you. The remaining records have your IDs:
foreach ($after_collection as $after_item) {
foreach ($input_collection as $input_item) {
if ( $after_item->compare_content($input_item) ) {
$intersection_array[] = $after_item;
}
}
}
This is just how a common person would solve it in a real world, with parts of code. Thanks to autoincrement it should get smallest possible amount of records to check against, so they will not take lot of processing. This is not the final "copy & paste" code - eg. you have to create your own function compare_content() according you your needs.