Hi I am having an issue with updating a users last login time in my database, if I set it to update a different column it works perfectly, but it just does not work when i try to update the specific column "lastlogin".
My code:
#mysql_query("UPDATE my_users SET lastlogin=NOW() WHERE id=".$_SESSION["id"]);
My DB column:
column name: lastlogin
type: datetime
Null: No
Default: 0000-00-00 00:00:00
Anything wrong with the way the column is setup in the DB? Like I mentioned above if I was to tell it to put NOW() in another column it works fine.
Solved. There was another similar statement further down which was over riding this one! How stupid of me but easy to miss!
use mysql_error to try and find what is wrong, then post that into here so we can help if you need it. (Would comment but to low rep)
From my experience in the past, mysql_query() doesn't necessarily substitute variables before executing sql. Try writing in this format. Also use mysql_error to check if there are any issues with your code execution:
$sql = "UPDATE my_users SET lastlogin=NOW() WHERE id=".$_SESSION["id"];
mysql_query($sql) or die(mysql_error());
If there is no error, then there are few possibilities as to why the laslogin entry is not happening:
$_SESSION["id"] does not hold any value and no value is being passed to mysql.
There is no id matching with $_SESSION["id"].
To debug:
Also try updating some other columns.
You might also want to check if you are using correct extensions like PDO..
Also found that, earlier version of mysql doesn't support updating datetime column with now(). In that case try resetting column type to TIMESTAMP. Refer this for details: https://bugs.mysql.com/bug.php?id=27645
Related
I am experiencing something so basic, yet so annoying that I thought I had to put it out to the wider community to save my sanity.
I am using a table within a database to store some very basic data. There is only two columns, Id and Campaign. I only want to use a single row of the table, however, campaign will be updated at various points. I have set up the table as follows:
$sql = "CREATE TABLE IF NOT EXISTS TestCampaign(id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
Campaign CHAR(20))";
Initially I write to the table to insert a null CHAR in campaign:
$sql = "INSERT INTO TestCampaign (Campaign) VALUES ('None')";
The based on a specific text field being filled in on an html form followed by a submit button press I intended to do the update of the campaign field:
$sql = "UPDATE TestCampaign SET Campaign = '$Test' WHERE id = '1'";
$Test is the POSTED campaign name from the form. Unfortunately although the INSERT works fine the UPDATE doesn't. I have checked the permissions and I have ALL on this database. I have also checked the syntax with various sites and it seems that it is fine.
Interestingly I do not get an error when I echo:
echo " ".mysqli_error($con);
I'm sure I have made some basic error somewhere but I have been looking at it for so long and changing the syntax that I can't seem to spot it.
Any help would be appreciated.
UPDATE:
I have played around with the code and it seems as though the UPDATE code does work, however, It only works when it is the next line of code after the INSERT. In fact I have found that it works as long as it is not where I need it to be. I have it placed in 'if' statement that is run only on a specific button press on the form:
if(isset($_POST['TestID']))
{
Some Code;
$sql = "UPDATE TestCampaign SET Campaign = '$Test' WHERE id = '1'";
Some More Code;
}
I have checked the rest of the code in the 'if' statement and it seems solid.
Is this odd behaviour or have I missed something?
SOLVED
Finally found out what the problem was, it ended up that when exiting the first 'if' statement as expected the html form code was revisited which must have closed the connection to the database, when the button was pressed to run the second 'if' statement there was a connection to MySQL but no connection to the database I needed access to. A quick fix to re-connect and all works fine.
$sql = "UPDATE TestCampaign SET Campaign = '$Test' WHERE id = 1";
Is the only thing I think is wrong... What do you get with :
Select * from TestCampaign
have you set up any triggers based on this table name? After update, before update triggers may prevent you from storing the required data on the table.
Also, MySQL may use 0 as id value if you don't specify the value of the id at sending insert command. Are you sure the value of your id is 1 in the record you want to update? If you have run insert statements before on your table, the id may be a larger number than 1, because of the MySQL indices (I guess this may be the problem).
I don't know how exactly PHP statements are processed when sending them to MySQL, but I would recommend you to use PDO statements, the PHP syntax would look something like this:
$sql = $pdo->prepare("UPDATE TestCampaign SET Campaign = ? WHERE id = ?");
$sql->bindParam(1, $Test);
$sql->bindParam(2, 1);
$sql->execute();
Tutorial: http://wiki.hashphp.org/PDO_Tutorial_for_MySQL_Developers
I would also echo your $Test variable to check what is stored in it.
Hope it helps...
Finally found out what the problem was, it ended up that when exiting the first 'if' statement as expected the html form code was revisited which must have closed the connection to the database, when the button was pressed to run the second 'if' statement there was a connection to MySQL but no connection to the database I needed access to. A quick fix to re-connect and all works fine.
Ok, let say we have two rows:
member_id, name
Let say member_id = 15 and name = 'John';
I want to UPDATE this data and do the following query:
mysql_query("UPDATE members SET member_id = 14, name = 'Peter' WHERE member_id = 15
This is just an example, but is it possible that mysql would fail and UPDATE for example only name row. So, after completing mysql_query above, it would become member_id = 15 and name = 'Peter';
It is just an example. Today, a similar situation happened in my website and I checked my code hundred times and I see no errors and there hadn't been no same errors before it at all.
So, should I recheck my code one hundred times more, or it can happen?
Thank you very much.
According to the spec, single UPDATE statements are atomic; ie: either it updates all columns or it doesn't update any of them.
So no, it shouldn't happen. But of course there could be a bug with MySQL.
Put or die(mysql_error()); after your query so that if this really is happening then you would at least know about it.
I think it should not happen that it would become member_id = 15 and name = 'Peter'. The SQL syntax is right as far as i can see and it seems all good. If something wrong happens to your database and your query is executed in that moment God only knows what could happen. Despite this, most of the time either the query is executed entirely or it is not, making mysql_query() return false.
You should, as already suggested at least check if there where any error with a code such as the following if you are in an online business website:
mysql_query($sql) or die('An error occurred');
or something like as follows if you are in debug mode:
mysql_query($sql) or die(mysql_error());
I'm not as sure as everyone else that single-row updates are atomic. MySQL differs from standard SQL in that it does the column assignments of a single-table UPDATE left-to-right. That means member_id = 14 is done before name = 'Peter'. If name = 'Peter' violates a constraint, or triggers another update that fails, then that assignment will fail. However, whether the statement as a whole fails or not may depend on various factors, including whether the table is using a transaction-safe engine.
I have a website with a sales and wanted page, which uses a query to return all of the sales & wanted ads into a recordset. It's been working for 4-5years without incident, but suddenly stopped working on Friday. My ISP tell me they have implemented v5 of MySQL, which seems to have caused the problem.
The query is below:
$query = "select * from $table order by uidno desc limit $from,$max_results";
It's executed via the following command
$recordset = mysql_query($query);
if($recordset == false)
{
echo("Could not retrieve comment. Please try later<br>");
echo("060211<br>");
return;
It's no longer able to load the comments into the recordset. Also the statement to populate the table is no longer populating the fields in the table correctly, though a new row is being created.
The statement is below:
$inputdata = "INSERT INTO $table(date,name,email,suggestion) values('$today','$inputname','$email','$suggestion')";
And it is executed via:
$outcome = mysql_query($inputdata);
The structure of the table is as follows:
uidno int(11) extra=AUTO_INCREMENT Null=no default = none
date date default 0000-00-00
Name varchar(60)
Email varchar (60) Null=yes Default = NULL
Suggestion blob attrbutes=binary null=no
Please help - I don't understand what changes I need to make to the syntax to make these queries compatible with MYSQL v5.
Update:
I added the echo mysql_error(); and it appears to output the following:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-10,10' at line 1
So this indicates an error in the syntax - but I've no idea what the error is.
http://dev.mysql.com/doc/refman/5.0/en/select.html
The LIMIT clause can be used to constrain the number of rows returned by the SELECT statement. LIMIT takes one or two numeric arguments, which must both be nonnegative integer constants (except when using prepared statements).
Column, index, stored routine, and
event names are not case sensitive on
any platform, nor are column aliases
so your lowercase column names in code and upper case column names in mysql structure should not be the problem.
I have an MS Access database (intolerably enough), and communicating with it through PHP (ODBC).
There is a DateTime field that I have to include in my INSERT statement. This field is NOT defined as "Required" in Access, meaning that it is indeed NULL-able, and in fact some of the rows in the Access database are already NULL.
The problem I'm having is simple: How to insert NULL through SQL? All the results I've found online have addressed it from something like Visual Basic or C#, whereas I'm using SQL through ODBC in PHP.
I have already tried the following:
INSERT INTO table_name (datetime_field) VALUES (NULL)
INSERT INTO table_name (datetime_field) VALUES (#NULL#)
INSERT INTO table_name (datetime_field) VALUES ('NULL')
INSERT INTO table_name (datetime_field) VALUES ('#NULL#')
INSERT INTO table_name (datetime_field) VALUES ('')
(There's about 30 other columns in my query.)
The exact error I get is 'Data type mismatch in criteria expression' when I try '' or NULL. The others return a parse error (understandably).
Please note that I have to include the field in the INSERT statement. The field has a default value, but in many cases the original data that I'm transporting has a NULL that must also be a NULL in the target database.
Thanks in advance!
Try the following. It works for me:
INSERT INTO sometable ( somedate, somethingelse )
SELECT Null AS Expr1, "foo" AS Expr2;
Basically, you are wrapping the null in the select query and letting SQL figure out how to represent it to the insert.
-- EDIT --
This SHOULD also work:
INSERT INTO sometable ( somedate, somethingelse )
values (Null , "foo");
But for some reason it doesn't with my default install.
On I hunch, I switched my DB from ANSI-89 to ANSI-92, and the VALUES method started working. I switched it back to ANSI-89, and it still works. Not only that, on ANY new database I create, it now also works. Weird... something in the installation must be getting changed, (and sticking) by the switching back and forth that's not just ANSI-89/92. This seems to be why we were getting different results.
You can switch the database ocwe by going to Office Logo->Access Options->OBJECT DESIGNERS->QUERY DESIGN. Change SQL Server Compatible Syntax (ANSI 92) - and checking "This database".
Ok, very odd.
I know you've already figured this out but there is also dbNull
INSERT INTO table_name (datetime_field) VALUES (DbNull.Value)
Try just leaving it blank
(values fld1,,fld2)
What are the libraries, you are using in order to talk to ODBC?
Could it be a problem with the syntax for null values, the way library interprets it?
See, if this page helps.
Note: I have not worked with PHP.
I have this type of error and
Try this.
INSERT INTO table_name (datetime_field) VALUES (DBNull.value)
It works fine for me.
Im wondering if the way i use to retrieve the id of the last row inserted in a postgresql table is efficent..
It works, obviously, but referencing on the serial sequence currval value could be problematic when i have many users adding rows in the same table at the same time.
My actual way is:
$pgConnection = pg_connect('host=127.0.0.1 dbname=test user=myuser password=xxxxx')or die('cant connect');
$insert = pg_query("INSERT INTO customer (name) VALUES ('blabla')");
$last_id_query = pg_query("SELECT currval('customer_id_seq')");
$last_id_results = pg_fetch_assoc($last_id_query);
print_r($last_id_results);
pg_close($pgConnection);
Well, its just a test atm.
But anyway, i can see 3 issues with this way:
Referencing on the customer_id_seq, if two user do the same thing in the same time, could happen that them both get the same id from that way... or not?
I have to know the table's sequence name. Becose pg_get_serial_sequence dont works for me (im newbie on postgresql, probably is a configuration issue)
Any suggestion/better ways?
p.s: i can't use the PDO, becose seem lack a bit with the transaction savepoint; I wont use zend and, in the end, i'll prefer to use the php pg_* functions (maybe i'll build up my classes in the end)
EDIT:
#SpliFF(thet deleted his answer): this would works better?
$pgConnection = pg_connect('host=127.0.0.1 dbname=test user=myuser password=xxxxx')or die('cant connect');
pg_query("BEGIN");
$insert = pg_query("INSERT INTO customer (name) VALUES ('blabla')");
$last_id_query = pg_query("SELECT currval('customer_id_seq')");
$last_id_results = pg_fetch_assoc($last_id_query);
print_r($last_id_results);
//do somethings with the new customer id
pg_query("COMMIT");
pg_close($pgConnection);
If you use a newer version of PostgreSQL (> 8.1) you should use the RETURNING clause of INSERT (and UPDATE) command.
OTOH if you insist on using one of the sequence manipulation functions, please read the fine manual. A pointer: "Notice that because this is returning a session-local value, it gives a predictable answer whether or not other sessions have executed nextval since the current session did."
Insert and check curval(seq) inside one transaction. Before commiting transaction you'll see curval(seq) for your query and no matter who else inserted at the same time.
Don't remember the syntax exactly - read in manual (last used pgsql about 3 years ago), but in common it looks like this:
BEGIN TRANSACTION;
INSERT ...;
SELECT curval(seq);
COMMIT;
ex. minsert into log (desc,user_id) values ('drop her mind',6) returning id