My database table contains an eloquent query
click here to see Database Table Snapshot
.I have fetched the query from database.Now problem is that I'm unable to execute the query that is in the collection.
I have Tried eval() to execute the query present the collection.But eval() is not executing it.
eval("\"$tempdata\";");
$tempdata contains the query that is in the database table.
You need to add return when using eval.
Try:
eval("return $tempdata;");
Related
I'm a beginner with PDO and MySQL, so here's my question :
How can I be sure that when performing an INSERT .. SELECT (or MULTIPLE INSERT)
all data will be inserted in database?
I know there is a rowCount() function but the number of rows inserted is dynamic.
The only way I see would be to make a SELECT count(*), and then compare it with the rowCount(), but I'm not sure I'm doing it the right way.
And if not all data were inserted, is it possible to get rows which didn't work?
Also, is it possible that a SELECT query fails and retrieves only a few part of the data? (ex : It must retrieve 1000 rows but due to some failure, it retrieves 700) Or it's all or nothing?
Thanks for the help.
How can I be sure that when performing an INSERT .. SELECT (or MULTIPLE INSERT) all data will be inserted in database?
You should tell PDO to throw an exception in case of error and thus there will be a PHP error in case of a failed query.
I know there is a rowCount() function
Row count has nothing to do in your case.
And if not all data were inserted, is it possible to get rows which didn't work?
It is advised to redo all the successful yet queries instead. To do so you have to wrap your inserts in a transaction.
However, if you want to keep alll the previous inserts in place, you may wrap execute call in a try and catch operator and do whatever workaround inside.
Also, is it possible that a SELECT query fails and retrieves only a few part of the data?
No.
I' am using MySQLI Wrapper as stated in the docs about running rawQuery. Since it doesn't have any function to search database I had write my own. Below is the code that am using.
$songs = $db->ObjectBuilder()->rawQuery('SELECT * FROM songs WHERE song_name LIKE ?', array('%test%'));
The query returns empty results, yes there are data in the database which should match the search keyword. Any idea what am I doing wrong in the Query?
I don't know the structure and content of songs but your code seems to be correct. You can try if problem persists when array('%test%') is inserted into query by inserting this manually. Try to execute this:
$db->ObjectBuilder()->rawQuery("SELECT * FROM songs WHERE song_name LIKE '%test%'");
If this query returns empty results then I would suspect that something wrong is either in your query or in the database. Otherwise, there is something wrong with rewriting parameters by rawQuery function.
I'm trying to refine my database access classes to help at the time of processing form data. What I'm trying to accomplish is this:
add an SQL query to my connection object.
classify the SQL query by its commands and arguments.
use the classification data to automatically add the required attribute to a given form input tag (and, optionally, insert a given or corresponding RegEx for advanced matching).
add a session-driven temporary object holding the form members to check for both completeness and compliancy with a given set of rules or matches.
execute the SQL query once all the given requirements are satisfied.
Then, the way to proceed (in my actual code) is like this:
if (!empty($data = \Helpers\Forms\getData($_POST))) {
if (!empty($rules = \Helpers\Forms\getRules($_POST))) {
if ($data->isCompliant($rules)) {
// rest continues here...
}
}
}
So far, I've got steps 1, 3 and 5 fully completed. I got steps 2 and 4 just partially implemented because I need a way to do a metadata scan on a given prepared SQL query and that's where I'm a bit lost.
According to the PDO manual, the columnCount() method doesn't provide an accurate result until the execute() method is called.
However, the execute method actually executes the query and I don't want to do it because if it's a SELECT query, it would actually be ok but not for a INSERT, DELETE, UPDATE or any other kind of query.
So my question is... is there any way to get the column count for a given SQL query without executing it? Or maybe... is there a way to perform a dummy execution of a given SQL query to obtain this column count value?
Ok, so if I set into a variable an sql_query like so:
$query = mysql_query("..");
and call multiple mysql_result's like so:
mysql_result($query, 0);
mysql_result($query, 1);
mysql_result($query, 2);
How many queries will the page call to the server?
Only once? or three times?
When you execute mysql_query, It executes the sql and it keeps the result in an internal result structure. Next time when you call mysql_result, it fetches from that internal result.
For buffered query the reusult will be copying from MySQL server to PHP as soon as mysql_query is executed. For un-buffered query it'll be copied lazily.
So in both case Query executes only one time. But for un-buffered query it'll be fetched from MySQL server. every time you call mysql_result or mysq_fetch_*.Buffered and Unbuffered queries
You have given the answer yourself. If you are calling "query" function once, then it will only
execute once no matter how many times you parse its return value
$query = mysql_query("..");
When you run the above code then query gets executed and the returned resource is in $query variable. Then you can fetch data from it multiple times but query wont run again.
Here will be one query with database that's means Server. mysql_result() should not be mixed with calls to other functions that deal with the result set.
For more information you can visit : http://php.net/manual/en/function.mysql-result.php
Only *mysql_query* is executing against the mysql server. Only one query
mysql_result only fetches data from a mysql resource, it doesn't matter if you have previously gotten it from a query in code or managed to get it from another source.
From PHP 5.5.0 onwards this function is deprecated; the new way to perform this action would be to create a mysqli object and use over the functions mysqli::query and mysqli::fetch_field
Can the php function mysql_insert_id() return no result after processing the INSERT query in mysql db?
Just to clarify. There was a script performing by cron on the production site. It contained a cycle for generating invoices for users. Each iteration consists of a INSERT db query and the mysql_insert_id() operation going right after the query - to fetch the generated invoice number. A set of iterations were performed without fetching the last inserted number.
Can it be caused by high db server load or by some other reasons that are not linked to the problem at the php code site?
Any help would be appreciated!
Offhand, I can think of a few cases where MySQL wouldn't return the ID:
The table you're inserting into doesn't have an AUTO_INCREMENTed primary key.
You're inserting multiple rows at once.
You're calling mysql_insert_id() from a different connection than the INSERT query was executed.
The INSERT query didn't succeed (for instance, it encountered a deadlock). Make sure you are checking the return value from mysql_query(), then use mysql_errno() and mysql_error().
MySQL docs have a full list of conditions and details on how this function works.
Of course, it's also possible there is a bug in MySQL, which would depend on which version of MySQL you are using.
If you're running the commands through a shell script, and run them both separately as in;
mysql -e "insert into table ( field1 ) values ( 'val1' );" "database"
lastId=`mysql -e "select last_insert_id();" "database"`
Then that won't work as the second call makes a new connection to the server. You need to do something like the following, as it is all done within a single database call / connection;
lastId=`mysql -e "
insert into table ( field1 ) values ( 'val1' );
select last_insert_id();
" "database"`
You'll need to look up the extra parameters required for the MySQL command to remove formatting and header row - I'm afraid I can't remember them off the top of my head!