In my project, I must know first and last key of child to do something. I have query same below, I use 'i' to find first but I don't know how to get last key? Have any ways to set if Firebase query complete will do function with child_added? .In test, console.log(last) but is undefinded
var i = 0;
myDataRef.limitToLast(10).on('child_added', function (snapshot){
if( i == 0)
{
first = snapshot.key;
}
renderInfo(snapshot.key, snapshot.val(), 'new');
last = snapshot.key;
});
console.log(last)
Related
I new in kotlin , i want to update an item in lists.
I use this code:
var index: Int
for (record in recordList)
if (record.id == updatedHeader?.id) {
index = recordList.indexOf(record)
recordList.add(index, updatedHeader)
}
but it cant do this, because of ConcurrentModificationException
Assuming that recordList is a MutableList and val (so, you'd like to modify the records in place), you can use forEachIndexed to find the records you care about and replace them.
This did not cause a ConcurrentModificationException:
recordList.forEachIndexed { index, record ->
if(record.id == updatedHeader?.id) recordList[index] = updatedHeader
}
On the other hand, if you redefine recordList as a non-mutable list, and a var, you could rewrite the entire list using map:
recordList = recordList.map { if(it.id == updatedHeader?.id) updatedHeader else it }
Of course, you could call .toMutableList() on the end of that if you wanted to turn your List into a MutableList.
If there's a single record with the given id in the list, you can find its index and add the header at that index:
val index = recordList.indexOfFirst { it.id == updatedHeader.id }
if (index >= 0)
recordList.add(index, updatedHeader)
If there are multiple records with the given id and you want to prepend header before each of them, you can use get listIterator and use its methods to modify the list during the iteration without getting ConcurrentModificationException:
val iterator = recordList.listIterator()
for (record in iterator) {
if (record.id == updatedHeader.id) {
iterator.previous() // move to the position before the record
iterator.add(updatedHeader) // prepend header
iterator.next() // move next, back to the record
}
}
I have table with multiple customerKey values assigned to a numeric value; I wrote a script where foreach row of data I scan whole table to find all values assigned to the current customerKey and return a highest one;
I have a problem with performance - script processes around 10 records per second - any ideas how to improve this or maybe propose an alternative solution plesae?
function getLastest() {
var date = app.models.magicMain.newQuery();
var date_all = date.run();
date_all.forEach(function(e) { // for every row of date_all
var temp = date_all.filter(function(x) {
return x.SubscriberKey === e.SubscriberKey; // find matching records for the current x.SubscriberKey
});
var dates = [];
temp.forEach(function(z) { // get all matching "dates"
dates.push(z.Date);
});
var finalValue = dates.reduce(function(a, b) { // get highest dates value (integer)
return Math.max(a, b);
});
var record = app.models.TempOperatoins.newRecord(); // save results to DB
record.email = e.SubscriberKey.toString() + " " + finalValue.toString();
app.saveRecords([record]);
});
}
The only suggestion I have would be to add:
var recordstosave = [];
At the top of your function.
Then replace app.saveRecords([record]) with recordstosave.push(record).
Finally outside of your foreach function do app.saveRecords(recordstosave).
I saw major processing time improvements doing this rather than saving each record individually inside a loop.
I'm trying to implement a table valued function (as a SQLite virtual table).
It's a function that would take a string and return a table with all the words of the string.
If I call it with literal values like below, it works fine.
SELECT word FROM splitstring("abc def ghi")
If, however, I call it with a column from another table it doesn't work:
SELECT a.Name, word FROM article a, splitstring(a.Text)
The xBestIndex method gets called all right, but right after that, I get an exception from the ExecuteReader method. The exception message is "xBestIndex malfunction". The xFilter method does not get called because of the exception.
My xBestIndex implementation is simple, it just marks the parameter so I can see it in xFilter:
public override SQLiteErrorCode BestIndex(SQLiteVirtualTable table, SQLiteIndex index)
{
index.Outputs.ConstraintUsages.ElementAt(0).argvIndex = 1;
index.Outputs.ConstraintUsages.ElementAt(0).omit = 1;
return SQLiteErrorCode.Ok;
}
Am I'm doing something wrong or is it impossible to pass non-literal parameters to table valued functions?
Found the issue! I was using constraints that had usable=0. The BestIndex method gets called multiple times by SQLite, the second time with a non-usable constraint.
Here is the fixed body of the BestIndex method.
public override SQLiteErrorCode BestIndex(SQLiteVirtualTable table, SQLiteIndex index)
{
if (index.Inputs.Constraints.Count() != 2)
throw new ArgumentException("The generate_series function requires two integer (long) parameters!");
if (index.Inputs.Constraints.All(c=>c.usable == 1))
{
index.Outputs.ConstraintUsages.ElementAt(0).argvIndex = 1;
index.Outputs.ConstraintUsages.ElementAt(0).omit = 1;
index.Outputs.ConstraintUsages.ElementAt(1).argvIndex = 2;
index.Outputs.ConstraintUsages.ElementAt(1).omit = 1;
}
else
{
index.Outputs.IndexNumber = -1;
index.Outputs.EstimatedCost = double.MaxValue;
}
return SQLiteErrorCode.Ok;
}
Now I check the usable flag. When BestIndex gets called with a constraint with usable=0 I skip it i.e. return a high estimated cost for that index so it doesn't get used.
function _ahah_example_get_first_dropdown_options() {
$stid = oci_parse($conn, "SELECt code,descr1 FROM dbtest.regions");
oci_execute($stid);
$region= array();
while (($row = oci_fetch_array($stid, OCI_ASSOC))) {
$region[$row['CODE']]= $row['DESCR1'];
}
$region['']='Select';
oci_free_statement($stid);
oci_close($conn);
return drupal_map_assoc($region);
}
but it returns the key and the value equal I need the original key to be returne cause im using it's value in a javascript function?anyone would know how to return the original Key?
From your code, you should be able to skip drupal_map_assoc and just return $region. Give that a try and see if you like the results.
Reference http://api.drupal.org/api/drupal/includes--common.inc/function/drupal_map_assoc/6
I am trying to simply update the entity object and I get this error.. All the googling on the error I did takes me to complex explanations... can anyone put it simply?
I am working of of this simple tutorial
http://aspalliance.com/1919_ASPNET_40_and_the_Entity_Framework_4__Part_2_Perform_CRUD_Operations_Using_the_Entity_Framework_4.5
else
{
//UPDATE
int iFid = Int32.Parse(fid.First().fid.ToString());
oFinancial.fid = iFid;
oFinancial.mainqtr = currentQuarter;
oFinancial.mainyear = currentYear;
oFinancial.qtr = Int32.Parse(currentQuarter);
oFinancial.year = Int32.Parse(currentYear);
oFinancial.updatedate = DateTime.Now;
// ObjectStateEntry ose = null;
// if (!dc.ObjectStateManager.TryGetObjectStateEntry(oFinancial.EntityKey, out ose))
// {
dc.financials.Attach(oFinancial);
// }
dc.ObjectStateManager.ChangeObjectState(oFinancial, System.Data.EntityState.Modified);
}
dc.SaveChanges();
here is what is higher up in the code that I use simple to get me the primary key value.. probably a better way but it works.
var fid = from x in dc.financials
where iPhaseID == x.phaseid &&
strTaskID == x.ftaskid &&
strFundType == x.fundtype &&
iCurrentQuarter == x.qtr &&
iCurrentYear == x.year
select x;
If the oFinancial object came from your dc and you never manually detached it, then there is no reason to call the Attach method or to mess with the ObjectStateManager. As long as the dc knows about the object (which it does unless you detach it), then the ObjectStateManager will keep track of any changes you make and update them accordingly when you call dc.SaveChanges().
EDIT: Here's a refactored version of what you posted, hope it helps:
else {
//UPDATE
// as long as oFinancial was never detatched after you retrieved
// it from the "dc", then you don't have to re-attach it. And
// you should never need to manipulate the primary key, unless it's
// not generated by the database, and you don't already have another
// object in the "dc" with the same primary key value.
int iFid = Int32.Parse(fid.First().fid.ToString());
oFinancial.fid = iFid;
oFinancial.mainqtr = currentQuarter;
oFinancial.mainyear = currentYear;
oFinancial.qtr = Int32.Parse(currentQuarter
oFinancial.year = Int32.Parse(currentYear);
oFinancial.updatedate = DateTime.Now;
}
dc.SaveChanges();
One other thing: if iFid is the primary key, then you shouldn't mess with it as long as this object came from the dc. I believe the problem is that you're resetting the primary key (iFid) to the same value of another object within the dc, and EF4 is barking because you can't have two rows with the same primary key value in a table.