I've got a Coldfusion component, with a method in it called getColumnNames
This just queries a MySQL table, and returns the columnlist:
remote string function getColumnNames() {
qProcessCars = new Query();
qProcessCars.setDataSource('#APPLICATION.dsn#');
qProcessCars.setSQL('SELECT * FROM sand_cars WHERE 1 LIMIT 1');
qProcessCars = qProcessCars.Execute().getResult();
return qProcessCars.columnlist;
}
If I access this remotely in the browser, with page.cfc?method=getColumnNames, then I get the expected list of columns back.
However, if I try to access this from inside another method within the component, I get an error
remote string function otherFunction() {
...
sColumns = getColumnNames();
...
}
The error dump for the above code returns the message "The setSQL method was not found".
So can anyone help me find out why it works as a remote call, but not when called from another method inside the same component.
Problem may be caused some kind of race conditions. If you make few calls which interfere, at some point qProcessCars may already be query result, so invoking method is not possible.
I would try to make the qProcessCars variable local scoped (var qProcessCars = new Query();
) and/or try to use another variable name for query results.
Next possible step is to enclose the query building/executing code into named lock.
Ah I've answered my own question again. Sorry.
I've used the same name qProcessCars else where in the component, I hadn't put var in front of them.
I don't know WHY that was causing the problem, but it was. Maybe setSQL can only be called once per query object?
Related
Can anyone advise on the following problem:
I have a custom get_or_create method, which checks multiple fields and does some fancy stuff upon creation:
def fancy_get_or_create(name):
object = self.fancy_get(name)
if not object:
object = self.fancy_create(name)
return object
def fancy_get(name):
return self.filter(Q(name=name) | Q(alias=name)).first()
def fancy_create(name):
name = self.some_preprocessing(name)
return self.create(name=name, alias=name)
There's a race condition, where one request will check to see if the object exists, find nothing, and start creating it. Before that request finishes creating the object, another request comes in looking for the same object, finds, nothing, and begins creating the new object. This request will fail because the database has some uniqueness constraints (the previous request had just created the object, so the second request will fail).
Is there any way to prevent request 2 from querying the database until request 1 has finished? I was reading about transaction management and it did not seem like the solution, since the issue is not partial updates (which would suggest an atomic transaction), but rather the need to make the second request wait until the first has finished.
Thanks!
Update:
Here's what I went with:
try:
return self.fancy_get(name) or self.fancy_create(name)
except IntegrityError:
return self.fancy_get(name)
There are two viable solutions:
Use a mutex so only one process can access the fancy_get_or_create
function at the same time.
Capture the error thrown by the database and do something instead: ignore
that create, update the row instead of creating it, throw an
exception, etc.
Edit: another solution might be doing an INSERT IGNORE instead of just an INSERT. https://dev.mysql.com/doc/refman/5.1/en/insert.html
I used openAsync() function many times in my application to open SQLite connection with a success. But lately I added more code that also uses openAsync() and now I obtain this error:
Error: Error #3110: Operation cannot be performed while SQLStatement.executing is true.
at Error$/throwError()
at flash.data::SQLStatement/checkReady()
at flash.data::SQLStatement/execute()
at Function/com.lang.SQL:SQLErrorStack/deleteAllRecordsFromErrorStackTable/com.lang.SQL:connOpenHandler()[C:\work\Lang\trunk\actionscript\src\com\lang\SQL\SQLErrorStack.as:466]
It looks like the previous code didn't finish executing while another has started.
My question is: Why the execution of code in the second connection was rejected? I expected that some kind of a queue mechanism is used but it isn't. I looked everywhere for a solution how to cope with this problem but I failed. Can you help?
Can one opened DB connection solve the problem? What changes to my code should I apply then?
This is the code similar to this, that appears a few times in my application.
var SQLquery:String;
SQLquery = "DELETE FROM ErrorStackTable";
var sqlConn:SQLConnection = new SQLConnection();
sqlConn.addEventListener(SQLEvent.OPEN, connOpenHandler);
var dbFile:File = new File();
dbFile.nativePath = FlexGlobals.topLevelApplication.databaseFullPath_conf+"\\"+FlexGlobals.topLevelApplication.databaseName_conf;
sqlConn.openAsync(dbFile); // openDB
sqlSelect = new SQLStatement();
sqlSelect.sqlConnection = sqlConn;
sqlSelect.text = SQLquery;
function connOpenHandler(event:SQLEvent):void
{
sqlSelect.addEventListener(SQLEvent.RESULT, resultSQLHandler);
sqlSelect.addEventListener(SQLErrorEvent.ERROR, errorHandler);
sqlSelect.execute();
}
In Big Flex Applications Try To Avoid openAsync(db) calls because of the reusablity of the SQL code , if u have many sql statments to be executed then you should define more and more sql statments . and if you have dynamic result [Array] getting from web service (RPC ) then you will surely get an error although it is successful Execution and array insertion in the database will be fail .. Just Look at
the link Click Here You Will Get your answer
I just changed conn.openAsync(db); to conn.open(db); and it worked
Thanks
I use this code but its not working in cakephp and the code is:
$inserted = $this->get_live->query("INSERT INTO myaccounts (fname) values('test');
After this im using:
$lead_id = $this->get_live->query("SELECT LAST_INSERT_ID()");
It's working, but only one time.
Try this. Lots less typing. In your controller, saving data to your database is as simple as:
public function add() {
$data = "test";
$this->Myaccount->save($data);
// $this->set sends controller variables to the view
$this->set("last", $this->Myaccount->getLastInsertId());
}
You could loop through an array of data to save with foreach, returning the insertId after each, or you could use Cake's saveAll() method.
Myaccount is the Model object associated with your controller. Cake's naming convention requires a table called "myaccounts" to have a model class called "Myaccount" and a controller called "Myaccounts_Controller". The view files will live in /app/views/myaccounts/... and will be named after your controller methods. So, if you have a function add()... method in your controller, your view would be /app/Views/Myaccounts/add.ctp.
The save() method generates the INSERT statement. If the data you want to save is located in $this->data, you can skip passing an argument in; it will save $this->data by default. save() even automagically detects whether to generate an UPDATE or an INSERT statement based on the presence of an id in your data.
As a rule of thumb, if you're using raw sql queries at any point in Cake, you're probably doing it wrong. I've yet to run into a query so monstrously complex that Cake's ORM couldn't model it.
http://book.cakephp.org/2.0/en/models/saving-your-data.html
http://book.cakephp.org/2.0/en/models/additional-methods-and-properties.html?highlight=getlastinsertid
HTH :)
You can get last inserted record id by (works for cakePHP 1.3.x and cakePHP 2.x)
echo $this->ModelName->getLastInsertID();
Alternately, you can use:
echo $this->ModelName->getInsertID();
CakePHP 1.3.x found in cake/libs/model/model.php on line 2775
CakePHP 2.x found in lib/Cake/Model/Model.php on line 3167
Note: This function doesn't work if you run the insert query manually
pr($this->Model->save($data));
id => '1'
id is a last inserted value
I have a LinqToSql query that returns an array of Article objects like so:
return db.Articles.ToArray();
I then loop over this array and start to delete some items that meet a certain criteria, for simplicity let's say I delete them all, like so:
foreach (var item in array)
db.articles.DeleteOnSubmit(item);
The call to DeleteOnSubmit(entity) throws an invalid operation exception, it's message says "Can not delete an entity that has not been attached". I modified the code to get the entity first then delete it and it worked just fine. Here's the working code:
db.DeleteOnSubmit(db.Articles.Where(c=>c.Id == item.Id))
Now, I know it would work if I modified the repository to return IQueryable instead of a native array, I just don't understand why? Does ToArray has anything to do with this invalid operation exception?
Thanks.
ps: db is a reference to a DataContext object.
I suspect your using different DataContexts when selecting entities and when submitting changes. If this is the case, the error is natural and would still happen if you returned an IQueryable instead of a native array. Either you Attach an entity to the new data context or you use the same where you selected the initial entities.
Can you put it all in one method and try?
The answer is "No", it doesn't.
Unless you are using differen't db for delete than select (could happenw ithout you realize it) or db.ObjectTrackingEnabled is set to false somewhere.
As part of a web application users can upload files of data, which generates a new table in a dedicated MySQL database to store the data in. They can then manipulate this data in various ways.
The next version of this app is being written in CakePHP, and at the moment I can't figure out how to dynamically assign these tables at runtime.
I have the different database config's set up and can create the tables on data upload just fine, but once this is completed I cannot access the new table from the controller as part of the record CRUD actions for the data manipulate.
I hoped that it would be along the lines of
function controllerAction(){
$this->uses[] = 'newTable';
$data = $this->newTable->find('all');
//use data
}
But it returns the error
Undefined property:
ReportsController::$newTable
Fatal error: Call to a member function
find() on a non-object in
/app/controllers/reports_controller.php
on line 60
Can anyone help.
You need to call $this->loadModel('newTable') to initialize it properly. Cake needs to initialize $this->newTable properly, and call all the callbacks.
Of course, you don't need $this->uses[] = 'newTable';, that doesn't do anything except add another value to the $uses array.
try:
function controllerAction() {
$data = ClassRegistry::init('ModelNameForNewTable')->find('all');
}
If your table is called 'new_tables', your model name should be 'NewTable'