im really new to linq-to-SQL so this may sound like a really dumb question, i have the following code
var query = from p in DC.General
where p.GeneralID == Int32.Parse(row.Cells[1].Text)
select new
{
p.Comment,
};
how do i got about getting the result from this query to show in a text box ??
That would be:
TextBox1.Text = query.Single().Comment;
You have to filter the first result from your query. To do that, you can use Single() if you know the query only returns one value. You could also use First(), if the results might contain more than one row.
Also, if it's only a single value, you could rewrite the code to:
var query = from p in DC.General
where p.GeneralID == Int32.Parse(row.Cells[1].Text)
select p.Comment;
TextBox1.Text = query.Single();
Related
I'm trying to use SQL IN clause kind of feature in dynamoDB. I tried using withFilterExpression but I'm not sure how to do it. I looked at similar questions as they were too old. Is there a better method to do this? This is the segment of code I have got. I have used a static List as example but it is actually dynamic.
def getQuestionItems(conceptCode : String) = {
val qIds = List("1","2","3")
val querySpec = new QuerySpec()
.withKeyConditionExpression("concept_id = :c_id")
.withFilterExpression("question_id in :qIds") // obviously wrong
.withValueMap(new ValueMap()
.withString(":c_id", conceptCode));
questionsTable.query(querySpec);
}
I need to pass qID list to fetch results similar to IN clause in SQL Query.
Please refer to this answer. Basically you need to form key list/value list dynamically
.withFilterExpression("question_id in (:qId1, :qId2, ... , :qIdN)")
.withValueMap(new ValueMap()
.withString(":qId1", ..) // just do this for each element in the list in a loop programmatically
....
.withString(":qIdN", ..)
);
Mind there is a restriction on maxItems in 'IN'
// I have a custom metadata object named boatNames__mdt and I'm using two methods to get a list of picklist values in a String[];
First Method
Map<String, boatNames__mdt> mapEd = boatNames__mdt.getAll();
string boatTypes = (string) mapEd.values()[0].BoatPick__c;
// BoatPick__c is a textarea field (Eg: 'Yacht, Sailboat')
string[] btWRAP = new string[]{};
**btWRAP**.addAll(boatTypes.normalizeSpace().split(','));
Second Method
string[] strL = new string[]{};
Schema.DescribeFieldResult dfr = Schema.SObjectType.boatNames__mdt.fields.BoatTypesPicklist__c;
// BoatTypesPicklist__c is a picklist field (Picklist Values: 'Yacht, Sailboat')
PicklistEntry[] picklistValues = dfr.getPicklistValues();
for (PicklistEntry pick : picklistValues){
**strl**.add((string) pick.getLabel());
}
Map with SOQL query
Map<Id, BoatType__c> boatMap = new Map<Id, BoatType__c>
([Select Id, Name from BoatType__c Where Name in :btWRAP]);
When I run the above Map with SOQL query(btWRAP[]) no records show up.
But when I used it using the strl[] records do show up.
I'm stunned!
Can you please explain why two identical String[] when used in exact SOQL queries behave so different?
You are comparing different things so you get different results. Multiple fails here.
mapEd.values()[0].BoatPick__c - this takes 1st element. At random. Are you sure you have only 1 element in there? You might be getting random results, good luck debugging.
normalizeSpace() and trim() - you trim the string but after splitting you don't trim the components. You don't have Sailboat, you have {space}Sailboat
String s = 'Yacht, Sailboat';
List<String> tokens = s.normalizeSpace().split(',');
System.debug(tokens.size()); // "2"
System.debug(tokens); // "(Yacht, Sailboat)", note the extra space
System.debug(tokens[1].charAt(0)); // "32", space's ASCII number
Try splitting by "comma, optionally followed by space/tab/newline/any other whitespace symbol": s.split(',\\s*'); or call normalize in a loop over the split's results?
pick.getLabel() - in code never compare using picklist labels unless you really know what you're doing. Somebody will translate the org to German, French etc and your code will break. Compare to getValue()
(server side script)
This is a stripped down version of my code but what this should be doing is
find records where the "uniqueid" is equal to matchid
return 0 if there are less than two of these items
print the region of each item if there are two or more items
return the number of items
function copyFile(matchid){
var fileName = getProp('projectName')+" "+row[0];
var query = app.models.Files.newQuery();
query.filters.uniqueid._equals = matchid;
records = query.run();
var len = records.length;
if (len < 2) return 0;
console.log(row[2]+" - "+len);
for (var i=0; i<len;i++){
console.log("Loop "+i);
var r = records[i];
console.log(r.region);
}
return records.length
Strangely, it can only get at the region (or any of the other data for the FIRST record ( records[0]) for the others it says undefined. This is extremely confusing and frustrating. To reiterate it passes the len < 2 check, so there are more records in the set returned from the query, they just seem to be undefined if I try to get them from records[i]
Note: uniqueid is not actually a unique field, the name is from something else, sorry about confusion.
Question: WHY can't I get at records[1] records [2]
This was a ridiculous problem and I don't entirely understand the solution.
Changing "records" to "recs" entirely fixes my problem.
why does records[0] work, records[1] does not
but recs[0] and recs[1] both work.
I believe "records" has a special meaning and points at something regardless of assignment in this context.
I'm trying to pass an array parameter to the function executeSql of SQLiteObject in ionic to make it as a value for my sql query.
For example
var sqlQuery: string = "SELECT * FROM Property WHERE ID IN (?) AND Status = ?"
var ids: number[] = [123, 321, 456];
and I'm trying to pass it here,
var db: SQLiteObject
db.executeSql(sqlQuery, [ids, 0])
So basically I want to insert all the values of ids to the IN operator and 0 for Status. But I think the SQL interprets it differently.
I tried to pass it as a string db.executeSql(sqlQuery, [ids.toString(), 0]) to remove the unnecessary characters and such. But still it doesn't return anything.
NOTE
I know I need it to enclose to a promise or something, but I just sliced it and summarize it to remove the unnecessary codes. Thanks.
I tried to search all over but still can't find a definite answer, I just invent a work around for it by doing this method.
var ids: number[] = [123, 321, 456];
var sqlQuery: string = "SELECT * FROM Property WHERE ID IN (" + ids.toString() + ") AND Status = ?";
And pass it to executeSql function
var db: SQLiteObject
db.executeSql(sqlQuery, [0]);
This is just a work around. I'll still wait for a better solution. Thanks!
Personally, I know just enough Linq to be dangerous.
The task at hand is; I need to query the DAL and return a list of objects based on a date range. Sounds simple enough, however the date is a string, and for some reason it needs to stay a string.
I spent some time with this a while ago and got a solution working but I am iterating through a list of objects and selecting individual records by date one at a time, this is badddd! If the date range spans more than a few days its slow and I don't like it, and I've even busted a few of the Sr devs around here for doing iterative queries, so I definitely don't want to be a hypocrite.
Here is the crappy iteration way... each date pegs the database, which I hate doing.
- This works
DateTime start = Convert.ToDateTime(RecipientSearch.TransplantSearchStartDate);
DateTime end = Convert.ToDateTime(RecipientSearch.TransplantSearchEndDate);
var tempselectQuery = selectQuery;
while (start <= end)
{
tempselectQuery = selectQuery;
string sStart = Convert.ToDateTime(start).ToString(ResourceFormatting.DateOnly);
tempselectQuery = (ObjectQuery<DAL.Recipients>)tempselectQuery.Where(item => item.TransplantDate == sStart);
if (tempselectQuery.Count() != 0) TXPlistQueryDAL.AddRange(tempselectQuery.ToList());
start = start.AddDays(1);
}
Here is my attempt at trying to get my query to work in one db call
- This does not work... yet
DateTime start = Convert.ToDateTime(RecipientSearch.TransplantSearchStartDate);
DateTime end = Convert.ToDateTime(RecipientSearch.TransplantSearchEndDate);
List<string> sdates = new List<string>();
// Put my date strings in a list so I can then do a contains in my LINQ statement
// Date format is "11/29/2011"
while (start <= end)
{
string sStart = Convert.ToDateTime(start).ToString(ResourceFormatting.DateOnly);
sdates.Add(sStart);
start = start.AddDays(1);
}
// Below is where I get hung up, to do a .contains i need to pass in string, however x.TransplantDate
// includes time, so i am converting the string to a date, then using the EntityFunction to Truncate
// the time off, then i'd like to end up with a string, hence the .ToString, but, linq to entities
// thinks this is part of the sql query and bombs out... This is where I'm stumped on what to do next.
selectQuery =
(ObjectQuery<DAL.Recipients>)
from x in entities.Recipients
where sdates.Contains(EntityFunctions.TruncateTime(Convert.ToDateTime(x.TransplantDate)).ToString())
select x;
The error i get as follows:
I understand why I get the error, but I don't know the proper LINQ code to be able to acheive what I am trying to do. Any help will be greatly appreciated.
Ughh I feel dumb. I tried a bunch of tricky little things to get x.TransplantDate to just a date only string within my Linq query, E.G. 10/15/2011
where sdates.Contains(EntityFunctions.TruncateTime(Convert.ToDateTime(x.TransplantDate)).ToString())
Turns out it already is in the correct format in the database, and if i simplify it down to just
where sdates.Contains(x.TransplantDate) It works. The reason I wasnt getting any records returned was because I was testing date ranges that didnt have any data for those specific dates... UGHH.
So in conclusion this ended up working fine. And if anyone is doing something similar maybe you can learn from this example.
DateTime start = Convert.ToDateTime(RecipientSearch.TransplantSearchStartDate);
DateTime end = Convert.ToDateTime(RecipientSearch.TransplantSearchEndDate);
List<string> sdates = new List<string>();
while (start <= end)
{
string sStart = Convert.ToDateTime(start).ToString(ResourceFormatting.DateOnly);
sdates.Add(sStart);
start = start.AddDays(1);
}
selectQuery =
(ObjectQuery<DAL.Recipients>)
from x in entities.Recipients
where sdates.Contains(x.TransplantDate)
select x;