I can get a last update time from TABLES in information_schema. Can I get a USER who updated the database or a table?
As Amadan mentioned, I'm pretty sure there isn't a way to do this unless you record it yourself. However, this is a pretty straightforward thing to do: Whenever you perform an UPDATE query, also log in a separate table the user (as well as any other relevant information) that you want to record via an additional MySQL query. Something like this (written in PHP as you didn't specify a language, but the MySQL can be exported anywhere) will work:
// The update query
$stmt = $db->prepare("UPDATE table SET `col` = ? WHERE `col` = ?");
$stmt->execute(array($var1, $var2));
// Something in table has just been updated; record user's id and time of update
$stmt = $db->prepare("INSERT INTO log (userid, `time`) VALUES (?, NOW())");
$stmt->execute(array($userid));
Related
I want to execute a query that insert the insert id to one of the colums
And I want to know how to get the insert id
I read this answer Get inserted id from mysql insert procedure
but its talk about how to get the insert id after the query, And I want to get it when I do the query
I try to do:
$stmt = $db->prepare("INSERT INTO `files` (`name`, `fname`) VALUES (?, LAST_INSERT_ID() + ?)") or die($db->error);
$stmt->bind_param('ss', $name, $uniqid);
But its dosent work, I always get 56, also the contcat dosent work, what I need to do?
It is simply easier and better to save it after the insert. It is also highly unlikely you will get the correct id before the actual insert happens.
The most reliable way would be to use transactions.
Start a transaction
Insert the row
Update the insert id
Commit the transaction
The + is not a string concatenation operator in MySQL. Use CONCAT(string1, string2, ...).
In the wire protocol, mysql returns the same value as LAST_INSERT_ID() to the client after each query, unsolicited, and most libraries provide a way to access the most recently returned value. You didn't mention, but it looks like you're using mysqli in php, so you're looking for this:
$last_id = $db->insert_id;
It may look as if this is going to send a second query to ask the database for the id, but it isn't. It's returning the previously stored value.
http://php.net/manual/en/mysqli.insert-id.php
When I try to UPDATE and INSERT into two different tables on the same user action, it has an error where it only completes the command of either the insert or the update depending on which line comes last.
Is there a way to combine these two ?
$sql = "INSERT INTO photos(user, gallery, filename, uploaddate)
VALUES ('$log_username','profile pictures','$db_file_name',now())";
$sql = "UPDATE users SET avatar='$db_file_name'
WHERE username='$log_username' LIMIT 1";
Have you thought about using a trigger on the photos table? You could setup a tigger to execute every time an insert occurs that would update the users table.
Here's a link to check out:
http://www.mysqltutorial.org/create-the-first-trigger-in-mysql.aspx
1) Execute the first query and then execute the second query.
2) use transaction if mysql if want want the successful execution of both the queries otherwise transaction control mechanism will revert the change.
And what error are you getting when you are firing the queries one by one
I have a mySQL database and I have a Perl script that connects to it and performs some data manipulation.
One of the tables in the DB looks like this:
CREATE TABLE `mydb`.`companies` (
`company_id` INT NOT NULL AUTO_INCREMENT,
`company_name` VARCHAR(100) NULL ,
PRIMARY KEY (`company_id`) );
I want to insert some data in this table. The problem is that some companies in the data can be repeated.
The question is: How do I check that the "company_name" already exist? If it exist I need to retrieve "company_id" and use it to insert the data into another table. If it does not, then this info should be entered in this table, but I already have this code.
Here is some additional requirement: The script can be run multiple times simultaneously, so I can't just read the data into the hash and check if it already exist.
I can throw an additional "SELECT" query, but it will create an additional hit on the DB.
I tried to look for an answer, but every question here or the thread on the web talks about using the primary key checking. I don't need this. The DB structure is already set but I can make changes if need to be. This table will be used as an additional table.
Is there another way? In both DB and Perl.
"The script can be run multiple times simultaneously, so I can't just read the data into the hash and check if it already exist."
It sounds like your biggest concern is that one instance of the script may insert a new company name while another script is running. The two scripts may check the DB for the existence of that company name when it doesn't exist, and then they might both insert the data, resulting in a duplicate.
Assuming I'm understanding your problem correctly, you need to look at transactions. You need to be able to check for the data and insert the data before anyone else is allowed to check for that data. That will keep a second instance of the script from checking for data until the 1st instance is done checking AND inserting.
Check out: http://dev.mysql.com/doc/refman/5.1/en/innodb-transaction-model.html
And: http://dev.mysql.com/doc/refman/5.1/en/commit.html
MyISAM doesn't support transactions. InnoDB does. So you need to make sure your table is InnoDB. Start your set of queries with START TRANSACTION.
Alternatively, you could do this, if you have a unique index on company_name (which you should).
$query_string = "INSERT INTO `companies` (NULL,'$company_name')";
This will result in an error if the company_name already exists. Try a sample run attempting to insert a duplicate company name. In PHP,
$result = mysql_query($query_string);
$result will equal false on error. So,
if(!$result) {
$query2 = "INSERT INTO `other_table` (NULL,`$company_name`)";
$result2 = mysql_query($query2);
}
If you have a unique key on company_name in both tables, then MySQL will not allow you to insert duplicates. Your multiple scripts may spend a lot of time trying to insert duplicates, but they will not succeed.
EDIT: continuing from the above code, and doing your work for you, here is what you would do if the insert was successful.
if(!$result) {
$query2 = "INSERT INTO `other_table` (NULL,`$company_name`)";
$result2 = mysql_query($query2);
} else if($result !== false) { // must use '!==' rather than '!=' because of loose PHP typing
$last_id = mysql_insert_id();
$query2 = "UPDATE `other_table` SET `some_column` = 'some_value' WHERE `id` = '$last_id'";
// OR, maybe you want this query
// $query2a = "INSERT INTO `other_table` (`id`,`foreign_key_id`) VALUES (NULL,'$last_id');
}
I suggest you write a stored procedure(STP), which takes input as company name.
In this STP, first check existing company name. If it exists, return id. Otherwise, insert and return id.
This way, you hit DB only once
For InnoDB use transaction. For MyISAM lock table, do modifications, unlock.
I have a table that needs regular updating. These updates happen in batches. Unlike with INSERT, I can't just include multiple rows in a single query. What I do now is prepare the UPDATE statement, then loop through all the possibilities and execute each. Sure, the preparation happens only once, but there are still a lot of executions.
I created several versions of the table of different sizes (thinking that maybe better indexing or splitting the table would help). However, that did not have an effect on update times. 100 updates take about 4 seconds for either 1,000-row table or 500,000-row one.
Is there a smarter way of doing this faster?
As asked in the comments, here is actual code (PHP) I have been testing with. Column 'id' is a primary key.
$stmt = $dblink->prepare("UPDATE my_table SET col1 = ? , col2 = ? WHERE id = ?");
$rc = $stmt->bind_param("ssi", $c1, $c2, $id);
foreach ($items as $item) {
$c1 = $item['c1'];
$c2 = $item['c2'];
$id = $item['id'];
$rc = $stmt->execute();
}
$stmt->close();
If you really want to do it all in one big statement, a kludgy way would be to use the "on duplicate key" functionality of the insert statement, even though all the rows should already exist, and the duplicate key update will hit for every single row.
INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)
ON DUPLICATE KEY UPDATE 1=VALUES(a), b=VALUES(b), c=VALUES(c);
Try LOAD DATA INFILE. Much faster than MySQL INSERT's or UPDATES, as long as you can get the data in a flat format.
With the query below, I am trying to overwrite the 10th field in a MySQL table called "login" with the value NEW_VALUE. It's not working. Is the code below the correct method for overwriting existing data in a MySQL table?
Thanks in advance,
John
INSERT INTO login VALUES (NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'NEW_VALUE', NULL, NULL, NULL)
Just as an addition if anyone is still looking for an actual overwrite and not just an update. If you want to OVERWRITE always, (not update, just overwrite) you can use REPLACE instead of INSERT.
REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted. See Section 13.2.5, “INSERT Syntax”
http://dev.mysql.com/doc/refman/5.5/en/replace.html
No your code is not correct. You are adding a new row to your table not updating existing values. To update existing values, you want to use an update statement:
Upate a specific record
mysql_query("Update login SET nameOfYourColumn = '$cleanURL' WHERE primaryKey = idOfRowToUpdate")
To update the entire table
mysql_query("Update login SET nameOfYourColumn = '$cleanURL'")
If I've understood your question then the answer is "no". This isn't a mysql specific issue either, it's a generic SQL question. I'd strongly recommend going through an SQL tutorial, the best one I know if is here:
http://philip.greenspun.com/sql/
To answer your question, you should be able to do:
mysql_query("UPDATE login SET foo = '$cleanurl'");
where "foo" is the name of the tenth field.
A few other comments though:
Firstly, don't rely on the position of your fields, always explicitly list the field names. For example, it's better to go
INSERT INTO login (id, name) VALUES (1, 'Fred')
instead of
INSERT INTO login VALUES (1, 'Fred')
Point 2: You have directly embedded the value of $cleanurl into your query. Of course, you have to learn one thing at a time but be aware that this is very dangerous. If $cleanurl contains something like "'); DROP TABLE login;" then you might be in trouble. This is called SQL injection and is the source of constant security problems. Without going into too much detail, you should learn how to use prepared statements.
Point 3: PHP comes with a library called PDO which supports prepared statements. It also provides a common API for interacting with your database so if you find that you need to move from Mysql to another DBMS, PDO will abstract away most of the differences. By using the mysql_query function you lock yourself into using mysql.
You don't have to address all of these issues simultaneously but don't forget about them either, once you get familiar with PHP and SQL come back to the points about PDO and prepared statements.
First off: INSERT adds a new record to a table, UPDATE updates (overwrites) one or more existing records.
Second: UPDATE needs to know the name of the column to update, and which rows to update
UPDATE <tableName>
SET <columnName> = '$cleanurl'
WHERE <some condition to identify which record should be updated>
Thirdly: it's probably worth your while reading a few basic tutorials on MySQL/SQL