I have a table with with essentially three columns: user_id, setting, and value. I'm trying to use the following code:
INSERT INTO 'user_settings'(user_id, setting, value)
VALUES (1234, setting_1, 500)
ON DUPLICATE KEY UPDATE user_id = 1234, setting = setting_1'
This works great when creating a new setting, and it doen't generate duplicate records. The problem comes when I want to change the value- this won't work after the previous query has run:
INSERT INTO 'user_settings'(user_id, setting, value)
VALUES (1234, setting_1, 999)
ON DUPLICATE KEY UPDATE user_id = 1234, setting = setting_1'
No rows are affected. Clearly I'm missing something...
IMPORTANT: I am not able to alter the database (new primary keys or something).
UPDATE: It seems my understanding of ON DUPLICATE KEY is wrong. But the question remains- what is the most efficient way way to accomplish this?
Answered in a comment below: "If the Primary (or Unique) key is (user_id, setting), then use: ... ON DUPLICATE KEY UPDATE value=999".
Assuming you actually have a unique key on user_id, you are getting "no rows affected" because you aren't changing anything in the second query. I think what you want to do is update the value field as well:
INSERT INTO 'user_settings'(user_id, setting, value)
VALUES (1234, setting_1, 999)
ON DUPLICATE KEY UPDATE setting = setting_1,value=999
Without value in there, you're just setting the user_id and the setting field to the same values they were before, and MySQL doesn't need to update the record.
If you don't have a unique key on user_id, you'll have to find a different approach, as the ON DUPLICATE KEY UPDATE won't trigger.
Related
My columns are like this. column "a" is primary and auto incremantal.
a | b | x | y
When inserting new data, i need to check x and y columns shouldn't be exist together.
To clarify, imagine this row is at database with these values
(2, "example.com" , "admin", "123456")
I should able to insert both of these columns
(3, "example.com" , "user", "123456")
(4, "example2.com" , "admin", "123456")
But i shouldn't able to insert this column
(5, "example.com" , "admin", "5555555")
Because "example.com" and "admin" values already in database on a row. It doesn't matter column "y" is same or not.
How can i do this?
Create a composite unique index. This will allow any number of duplicates in the individual fields, but the combination needs to be unique.
CREATE UNIQUE INDEX ix_uq ON tablename (b, x);
...and use INSERT IGNORE to insert if the unique index is not violated. If it is, just ignore the insert.
INSERT IGNORE INTO test (a,b,x,y) VALUES (5, "example.com" , "admin", "5555555");
If you want to insert unless there's a duplicate, and update if there is, you can also use INSERT INTO ... ON DUPLICATE KEY UPDATE;
Ref: MySQL only insert new row if combination of columns (which allow duplicates) is unique
You want to let the database do the work. Although you can set up a condition within a query, that condition may not be universally true or someone might use another query.
The database can check this with a unique constraint or index. Actually, the unique constraint is implementing using a unique index:
create unique index unq_t_b_x on t(b, x);
(The columns can be in either order.)
The insert would then look like:
insert into t(b, x, y)
values ('example.com', 'admin', '5555555')
on duplicate key update b = values(b);
Note that the auto-incremented value is not included in the update.
The on duplicate key update just prevents the insert from generating an error. It is better than insert ignore because the latter will ignore all errors, and you just want to ignore the one caused by the duplicate key.
Hi I've been trying to get this to work, I thought I had it with mysql - INSERT... ON DUPLICATE KEY UPDATE, but no luck.
I have a table as such:
sessionID is unique,
productID references another table and is not unique, but not common, should be a max of 3 rows containing the same value,
sessionType is either 1, 2 or 3, and would link with productID,
I need to check if the table has a row where there is a matching pair of productID and sessionType, if there is then sessionDate & sessionCapacity in that row should be UPDATED, if there isn't then a new row inserted.
$vals = array($pID,$data['pSessionDate'],'1',$data['pQty'],$pID,$data['pSessionDate'],'1',$data['pQty']);
$db->Execute("INSERT INTO VividStoreSessions (pID,sDate,sType,sCapacity) VALUES (?,?,?,?) ON DUPLICATE KEY UPDATE pID=?,sDate=?,sType=?,sCapacity=?",$vals);
Hope that makes sense to someone and thanks in advance for any help!
Your insert looks valid. But, first you need a unique index/constraint:
create unique index unq_VividStoreSessions_productId_sessionType
on VividStoreSessions, productId, sessionType)
Then you can write the code to only use four parameters:
INSERT INTO VividStoreSessions (pID, sDate, sType, sCapacity)
VALUES (? ,?, ?, ?)
ON DUPLICATE KEY UPDATE sDate = VALUES(sDate), Capacity = VALUES(Capacity);
Finally, you need to ensure that sType only takes on the values of 1, 2, or 3. Perhaps you want to enforce this at the application layer. Otherwise, you need a trigger or foreign key constraint to ensure that there are only three rows.
I'm using ON DUPLICATE KEY UPDATE to handle duplicate inserts on a table, in order that they are discarded.
In my case it's a simple table storing tags:
id (int, PK, AI, unsigned, not null)
tag (varchar 25, not null, unique)
This is working fine, but I need to retrieve the ID - either the insert ID, on successful insert, or the existing ID, if it's a duplicate.
I'm getting insert ID = 0 where ON DUPLICATE KEY UPDATE fires, which I guess is expected behaviour since no insert took place.
Is there anyway I can get the existing ID, or am I headed to a separate read query?
You could add a third column ModifiedDate and use that:
insert into t(id, tag)
select id, tag
on duplicate key update ModifiedDate = now();
This will ensure that an update really occurs, and in turn, that LAST_INSERT_ID() returns a value.
I have a database: groupofficecom has two tables:
cal_events: id(Primary key), name, start_time, description,....
cf_cal_events: model_id (Primary key), col_1, col_2, col_3,....
I'm trying to execute the following code:
INSERT INTO groupofficecom.cf_cal_events (model_id,col_1,col_2,....)
SELECT groupofficecom.cal_events.ID, '0' AS col_1, '' AS col_2,....
FROM groupofficecom.cal_events
But it keeps giving me error #1062 - Duplicate entry '155' ('155' is the 'id' from cal_events) for key 'PRIMARY'
I want the primary key model_id to be the same value as id in cal_events because the table cf_cal_events is just complementary fields for cal_events (this is a program, so I can't change its database, it'll be gone on the first update)
Thank you guys!
This means there already is an entry with that id in the target table.
First, check how this can be.
Then, use one of the solutions described here as is appropriate:
"INSERT IGNORE" vs "INSERT ... ON DUPLICATE KEY UPDATE"
i.e. UPDATE or IGNORE.
You should use an ORDER BY with the select you have and the solution above to choose which entries get ignored (all but the first entry with IGNORE).
It is also possible that you want something different entirely, i.e. to use an UPDATE statement instead of an INSERT statement.
In fact I found a very good function, it's very similar to the INSERT but smarter:
REPLACE INTO database (column_1, column_2)
SELECT source_column1, 'value' AS column2
FROM table;
Or:
REPLACE INTO database (column_1, column_2)
VALUES ('value1', 'value2')
FROM table;
Works like magic!
It inserts new items to the destination table, and if it finds a row with the same primary key value, it erases it and re-inserts the new value (it works great for updating a table from another one)
I hope this solves your problem like it solved mine ;)
i am a bit concerned about one of my mysql queries... The following query receives a variable $DB_id... if a row with that primary key already exists the query performs an update.
$this->db->query(" INSERT INTO modules_text
( module_id,
module_content,
module_index
)
VALUES ( '{$DB_id}',
'{$content['text']}',
'{$index}'
)
ON DUPLICATE KEY
UPDATE module_content = '{$content['text']}',
module_index = '{$index}'
");
NOW THE THING THAT CONCERNS ME... There is no relation if the affected rows actually belong to the user. I would like to add a where statement to the UPDATE part or first make a subselecion of the rows which are permitted to be affected. SOmething like:
[...]
ON DUPLICATE KEY
UPDATE module_content = '{$content['text']}',
module_index = '{$index}'
WHERE module_post_id = '{$post]}'
Is this somehow possible... Until now i didnt find a solution... Any help would be very appreciated... THANKS A LOT!!!!!
Saludos Sacha!
This isn't how ON DUPLICATE KEY works. The update portion of the INSERT will only occur if there's a match for the UNIQUE key(s) or PRIMARY key for the table. (i.e.: The UNIQUE/PRIMARY key(s) are effectively the WHERE clause.)
See the full MySQL docs for more information.