How to use a prefix "N" in LINQ query? - entity-framework

I know how to use a prefix "N" in raw SQL query. (For unicode string)
But how to use a prefix N in LINQ query? any suggestion?
------------update------------
Below is the log generated by LINQ:
UPDATE [dbo].[Table1]
SET [Content] = #p1
WHERE ([ID] = #p0)
-- #p0: Input BigInt (Size = -1; Prec = 0; Scale = 0) [3]
-- #p1: Input Text (Size = -1; Prec = 0; Scale = 0) [こんにちは]
There's no N in the above generated SQL statement.
(Note I've set datatype of Content as nvarchar)

you can use EntityFunctions.AsUnicode Method

Related

How to do a select statement query with comma separator?

I need to do a simple query, Select Statement
I want to search in Table all record with value "ValueA, ValueB".
If I use this code, not work well:
String255 valueToFilter;
valueToFilter = 'ValueA, ValueB';
select count (RecId) from MyTable
where MyTable.Field like valueToFilter ;
But not working, I need to keep all record with value "ValueA" or "ValueB", if in the file there is value like : "ValueA, ValueC" I want to get too.
I don't know the number of values (valueToFilter).
Thanks!
From my point of view the easiest way to accomplish this is to split your filter string:
String255 valueToFilterA = 'ValueA';
String255 valueToFilterB = 'ValueB';
;
select count (RecId) from MyTable
where MyTable.Field like valueToFilterA
|| MyTable.Field like valueToFilterB;
If you don't know the number of values you should use query object to add ranges dynamically:
Query query = new Query();
QueryRun queryRun;
QueryBuildDataSource qbds;
QueryBuildRange queryRange;
container conValues;
;
qbds = query.addDataSource(tableNum(MyTable));
for (i = 1; i <= conlen(conValues); i++)
{
queryRange = qbds.addRange(fieldNum(MyTable, Field));
queryRange.value(SysQuery::valueLike(conPeek(conValues, i)));
}
queryRun = new QueryRun(query);
info(strFmt("Records count %1", SysQuery::countTotal(queryRun)));

Initialize generator with existing value

I am trying to set a generator with a value that is in some table, I have already seen this question How to set initial generator value? and did what they suggested but I don't know where am I going wrong here.
set term #
execute block
as
declare i int = 0;
begin
i = (select max(some_col) from Table);
gen_id(some_gen,-(gen_id(some_gen,0))); ---set some_gen to 0
gen_id(some_gen,:i); --- set to i
end #
set term ;#
The problem with your code is that you can't execute gen_id in isolation; the parser expects gen_id (or more precisely: a function call) only in a place where you can have a value (eg in a statement or an assignment). You need to assign its return value to a parameter, for example:
set term #;
execute block
as
declare i int = 0;
declare temp int = 0;
begin
i = (select max(id) from items);
temp = gen_id(GEN_ITEMS_ID, -(gen_id(GEN_ITEMS_ID, 0))); ---set some_gen to 0
temp = gen_id(GEN_ITEMS_ID, :i); --- set to i
end #
set term ;#
Please be aware that changing sequences like this is 'risky': if there are any interleaving actions using this same sequence, you might not actually get the result you expected (the sequence might end up at a different value than i and you might get duplicate key errors when another transaction uses the sequence after you subtract the current value (set to 0) and before you add i.
As also noted in the comments, you can also replace your code with:
set term #;
execute block
as
declare i int = 0;
declare temp int = 0;
begin
i = (select max(id) from items);
temp = gen_id(GEN_ITEMS_ID, :i - gen_id(GEN_ITEMS_ID, 0));
end #
set term ;#
Doing it in one statement will reduce the risk of interleaving operations (although it will not remove it entirely).
If you want to use "execute block", you may use something like :
execute block
as
declare i int = 0;
begin
i = (select max(some_col) from some_table);
execute statement ('set generator MY_GENERATOR to ' || :i);
end

wrong result with floating numbers

I have this table with 1 records. Im trying to compute something call Puntaje, to get the Puntaje Result I have to follow the following formula:
Puntaje = (Infracciones * 10) / Horas
Horas = Segundos / 60 / 60
I wrote the following script, but I have some doubt and problem.
1) Is there another way to assign the values to #variables or another way to compute the sum?
2) Why the Puntaje result is 0.00, have to be: 0.854
Im using MS SQL Server 2012
Can someone help me to resolve this? Thank you in advance.
/* content of table: #Customer_Drivers
DriverId Segundos KM QtyExcesos QtyFreAce QtyDesc Puntaje IDC
6172 717243 1782 17 0 0 0 0
*/
DECLARE #Customer_Drivers TABLE (
DriverId INT,
Segundos INT,
KM INT,
QtyExcesos INT,
QtyFreAce INT,
QtyDesc INT,
Puntaje INT,
IDC INT
);
SET NOCOUNT ON;
INSERT INTO #Customer_Drivers (DriverId, Segundos, KM, QtyExcesos, QtyFreAce, QtyDesc, Puntaje, IDC)
VALUES (6172, 717243, 1782, 17, 0, 0, 0, 0);
SET NOCOUNT OFF;
DECLARE #DriverId INT = 6172;
DECLARE #Horas INT;
DECLARE #QtyExcesos INT ;
DECLARE #QtyFreAce INT ;
DECLARE #QtyDesc INT ;
DECLARE #Infracciones INT;
DECLARE #Puntaje Decimal(18,2);
SET #Horas = (SELECT Segundos FROM #Customer_Drivers WHERE DriverId = #DriverId) / 60 / 60;
SET #QtyExcesos = (SELECT QtyExcesos FROM #Customer_Drivers WHERE DriverId = #DriverId);
SET #QtyFreAce = (SELECT QtyFreAce FROM #Customer_Drivers WHERE DriverId = #DriverId);
SET #QtyDesc = (SELECT QtyDesc FROM #Customer_Drivers WHERE DriverId = #DriverId);
SET #Infracciones = (#QtyExcesos + #QtyFreAce + #QtyDesc);
SET #Puntaje = ( #Infracciones * 10) /#Horas;
PRINT #Horas
PRINT #QtyExcesos
PRINT #QtyFreAce
PRINT #QtyDesc
PRINT #Puntaje
/* OUTPUT
199 -- #Horas
17 -- #QtyExcesos
0 -- #FreAce
0 -- #QtyDesc
0.00 -- #Puntaje must be = 0.854
*/
Even though #Puntaje is declared as Decimal(18,2), that doesn't mean your calculation will be treated as a decimal. The problem is that ( #Infracciones * 10) / #Horas is using all integers so this expression will result in the integer value 0. Then this integer 0 is converted to a decimal and stored in #Puntaje.
To fix this, you need to convert part of the expression to a decimal first so that the result will be a decimal:
SET #Puntaje = ( CAST(#Infracciones AS Decimal(18,2)) * 10) / #Horas
You are using integers in your calculation, so the result will be rounded off (or truncated) to the nearest integer. Use decimal values, or use 'cast' :
#Puntaje = (cast(#Infracciones as decimal(18,2)) * 10.0) / cast(#Horas as decimal(18,2))
Check my syntax - just typed this on without trying it
1) You can use SELECT #Horas = Segundos/3600, #QtyExcesos = QtyExcesos ... FROM [RS_Reports].[dbo].[Customer_Drivers] WHERE DriverId = #DriverId. This should work providing that there is one line of results.
2) Already answered by others, you have to divide by decimal to get a decimal, i.e. you'll have to convert #Horas to Decimal
From what I've learned. #variable should be some parameters light input parameter and output parameter.... Try to execute your Stored Procedure and see what you got in SQL Server Management Studio.
There should be a return value.

Check the Column Is NULL or NOT in SQL SERVER

I have a procedure in SQL Server 2008 R2, I want to enter the data to vol_Hours column and check it before if it is not null then plus the entry with old data that it in the column, if it's NULL then add the entry to the column without plus the NULL value.
I cannot add 2+NULL because it's = NULL.
MY Code Is:
create procedure updateVolunteerHours
#vol_ID int, #vol_Hours int
As
if vol_Hours is NULL
-- vol_Hours it is the Column Name
Update Personal_Information set vol_Hours = #vol_Hours where vol_ID = #vol_ID
else
Update Personal_Information set vol_Hours = #vol_Hours + vol_Hours where vol_ID = #vol_ID
In this case, just update the adding expression to use COALESCE (or ISNULL or CASE) and remove the IF statement entirely.
Update Personal_Information
set vol_Hours = COALESCE(vol_Hours, 0) + #vol_Hours
where vol_ID = #vol_ID
If both branches did entirely different things, then the conditional would have to be altered to use the results of a query.
IF EXISTS(SELECT * FROM Personal_Information
WHERE vol_ID = #vol_ID
AND vol_Hours IS NULL) ..
.. but that's just not needed here.

ADO.NET: How to have N parameters?

i need to mark a batch of rows in the database as "processed".
In the olden days, when things were easier, i would create some SQL that said:
UPDATE Readings SET IsProcessed = 1 WHERE ReadingDateTime IN (
"2010-10-07 22:02:13.327",
"2010-10-07 22:02:14.213",
"2010-10-07 22:02:15.595",
...
"2010-10-07 23:03:36.981")
by looping through a list of dates:
sql = "UPDATE Readings SET IsProcessed = 1 WHERE ReadingDateTime IN (";
foreach (DateTime datetime in dates)
{
sql = sql + CRLF+ DateTimeToSql(datetime)+",";
}
sql = sql+")";
And issue the SQL:
ExecuteNonQuery(connection, sql);
And all was good.
Now i want to try to do things the hard way; i want to try to use parameters:
sql = ???;
command.CommandText = sql;
DbCommand command = connection.CreateCommand();
foreach (DateTime datetime in readings)
{
command.Parameters.Add(new SqlParameter(???, SqlDbType.DateTime) {Value = datetime});
}
using (DbTransaction transaction = connection.BeginTransaction())
{
command.Transaction = transaction;
command.ExecuteNonQuery();
transaction.Commit();
}
The only trick is what to put in the sql string, and what to put in each iteration of the parameters loop. They need some name.
What's the recommended way to name arbitrary number of parameters?
I think what you could do is something like this:-
sql = "UPDATE Readings SET IsProcessed = 1 WHERE ReadingDateTime IN (";
for (int count=0; count<dates.Length; count++)
{
sql = sql + CRLF + ":param" + count;
}
sql = sql+")";
for (int count=0; count<dates.Length; count++)
{
command.Parameters.Add(new SqlParameter(":param" + count, SqlDbType.DateTime) {Value = datetime});
}
However, i think that having parameters specifically in this scenario is kind of unnecessary.
Considering that your dynamic values are dates and not strings, you can instead validate the dates directly using a TryParse to ensure that they are the correct datatype before you append them in your original solution!!
I dont know if you are achieving anything extra over that by using parameters in this case.
You can go as minimal as you like: the provider will accept parameters named #0, #1, etc. But if you want to be more descriptive, just use a base name of #ReadingDateTime, with an integer suffix from 0..n. Easy peasy.