I have a database with two tables, and wrote a relatively simple select statement that combines the data and returns me the fields I want. In my SQL developer software it executes just fine.
Now to execute it in my C# .NET Core application, I created a "fake" DbSet in my DbContext that doesn't have a proper table on the database. The Type of the DbSet is a Model that represents the resulting data structure of the select statement. I use the DbSet field to access the method FromSql() and execute the select like so:
List<ProjectSearchModel> results = _ejContext.ProjectSearch.FromSql(
#"SELECT combined.Caption, combined.Number FROM
(SELECT p.Caption, p.Number, CreateDate FROM dbo.Project AS p
UNION
SELECT j.Caption, j.Number, CreateDate FROM dbo.Job AS j) AS combined
WHERE combined.Caption LIKE '{0}%' OR combined.Number LIKE '{0}%'
ORDER BY combined.CreateDate DESC
OFFSET 0 ROWS
FETCH FIRST 30 ROWS ONLY", term)
.ToList();
The SQL does properly return data, I've tested that. But the result variable holds 0 entries after executing. In the documentation for FromSql() I found that with MS SQL Servers you have to use OFFSET 0 when using ORDER BY so that's what I did.
I have no idea what I'm doing wrong.
You need to use DbQuery<T> instead:
public DbQuery<Project> ProjectSearch { get; set; }
Then, you can issue arbitrary queries using FromSql on that. With DbSet, the query must be composable, which means it can only be a standard select, it must correspond to a real table, and must include all properties on the entity - none of which apply to the query you're trying to perform.
As #ChrisPratt said, one of my mistakes was using the DbSet class instead of the DbQuery class. But also, what drove me crazy is that my parameters didn't work. My mistake was putting them inside a string, which results in them not being recognized as parameters. So my SQL string should be
...
WHERE combined.Caption LIKE {0} + '%' OR combined.Number LIKE {0} + '%'
...
instead of
...
WHERE combined.Caption LIKE '{0}%' OR combined.Number LIKE '{0}%'
...
Related
I have some sqlserver sql that due to data can't be modified, which I currently run from Sqlserver. It uses a substring function. I want to stop running it from Sqlserver and create a user-accessible form in which the user enters a date and the script goes off and does it's thing and returns row data to the user.
Not overly familar with X++. I've looked at reports, querys, jobs, statement classes, not sure what's the correct path.
Below is the sql code.
'
select a.description,b.itemid, c.phantom,a.createddatetime,a.createdby
from sysdatabaselog A
inner join
bomversion B
on substring(a.description,1,11) = b.bomid
inner join
inventtable C
on b.itemid = c.itemid
where (table_ = 18 and logtype=1)
and a.CREATEDDATETIME > '2018-03-01' <-------- this would be user-supplied on the form
and c.phantom=1
'
What you're trying to accomplish is actually pretty high-level in AX and requires a several different dev techniques to accomplish it. I'm not going to do the entire thing for you, but I'll get you started and tell you what you need to do. These screenshots are from AX2012.
To accomplish the SUBSTRING() you need an AX View + String computed column.
For your view, you'll want an AX Query object to contain your joins OR you can just do a simple view on the BOMVersion table and then work against that.
Here's an example View and String computed column and the method for the computed column. I just used SalesTable and SalesId as the sample.
public static server str compSubStrSalesName()
{
str result;
result = strFmt("SUBSTRING(%1, 1, 5)",
SysComputedColumn::returnField(identifierStr(SubStringExample), // The name of your view
identifierStr(SalesTable_1), // The name of your view's datasource
identifierStr(SalesId) // The name of the field
)
);
return result;
}
I want to convert an SQL query into a JSONiq Query, is there already an implementation for this, if not, what do I need to know to be able to create a program that can do this ?
I am not aware of an implementation, however, it is technically feasible and straightforward. JSONiq has 90% of its DNA coming from XQuery, which itself was partly designed by people involved in SQL as well.
From a data model perspective, a table is mapped to a collection and each row of the table is mapped to a flat JSON object, i.e., all fields are atomic values, like so:
{
"Name" : "Turing",
"First" : "Alan",
"Job" : "Inventor"
}
Then, the mapping is done by converting SELECT-FROM-WHERE queries to FLWOR expressions, which provide a superset of SQL's functionality.
For example:
SELECT Name, First
FROM people
WHERE Job = "Inventor"
Can be mapped to:
for $person in collection("people")
where $person.job eq "Inventor"
return project($person, ("Name", "First"))
More complicated queries can also be mapped quite straight-forwardly:
SELECT Name, COUNT(*)
FROM people
WHERE Job = "Inventor"
GROUP BY Name
HAVING COUNT(*) >= 2
to:
for $person in collection("people")
where $person.job eq "Inventor"
group by $name := $person.name
where count($person) ge 2
return {
name: $name,
count: count($person)
}
Actually, if for had been called from and return had been called select, and if these keywords were written uppercase, the syntax of JSONiq would be very similar to that of SQL: it's only cosmetics.
in GORM (using grails) i need to combine in subselect multiple results into one value. (result of this subselect will be concatenated value on which i can make search / sort etc. ...)
Query is writen as HQL. Something like this in oracle
http://www.techonthenet.com/oracle/functions/listagg.php
Can be something like that achieved in HQL (e.g. GORM) ?
...
AND (
SELECT LISTAG(e.title) AS con FROM Entity e
WHERE Entity.searchKey = TRUE
AND e.parrent = par
AND LOWER(e.title) LIKE :search
) > 0
...
ORDER BY con ASC
thansk
Hibernate, and the HQL/GORM layers that sit on top of Hibernate, do not directly support database-specific functions like Oracle's LISTAGG(). There are, however, a few ways to use native SQL within Grails. If you would like to add your concatenated value to one of your domain objects, you can use GORM's derived property feature (http://grails.org/doc/latest/guide/GORM.html#derivedProperties).
Something along these lines:
class MyDomain {
Long parentId
String titleAgg
static mapping = {
titleAgg formula: '(SELECT LISTAGG(e.title) FROM Entity e WHERE e.parrent = parent_id)'
}
}
A second option would be to use the Grails-defined dataSource bean along with groovy.sql.Sql to execute native SQL statements. See here for an example.
I have following sql query in my hbm file. The SCHEMA, A and B are schema and two tables.
select
*
from SCHEMA.A os
inner join SCHEMA.B o
on o.ORGANIZATION_ID = os.ORGANIZATION_ID
where
case
when (:pass = 'N' and os.ORG_ID in (:orgIdList)) then 1
when (:pass = 'Y') then 1
end = 1
and (os.ORG_SYNONYM like :orgSynonym or :orgSynonym is null)
This is a pretty simple query. I had to use the case - when to handle the null value of "orgIdList" parameter(when null is passed to sql IN it gives error). Below is the relevant java code which sets the parameter.
if (_orgSynonym.getOrgIdList().isEmpty()) {
query.setString("orgIdList", "pass");
query.setString("pass", "Y");
} else {
query.setString("pass", "N");
query.setParameterList("orgIdList", _orgSynonym.getOrgIdList());
}
This works and give me the expected output. But I would like to know if there is a better way to handle this situation(orgIdList sometimes become null).
There must be at least one element in the comma separated list that defines the set of values for the IN expression.
In other words, regardless of Hibernate's ability to parse the query and to pass an IN(), regardless of the support of this syntax by particular databases (PosgreSQL doesn't according to the Jira issue), Best practice is use a dynamic query here if you want your code to be portable (and I usually prefer to use the Criteria API for dynamic queries).
If not need some other work around like what you have done.
or wrap the list from custom list et.
When you map a table to an object, every property created corresponds to one db column.
I want to execute a db function on a column before it gets mapped to the property, so the property gets the value returned by the db function, and not the column
I was trying to achieve that by Expression property of ColumnAttribute (as in the example below), so instead of BirthDate the usrFn_UTCToLocalTime(BirthDate) is returned
but it does not seem to be working and still gets pure value of the column.
[global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_BirthDate", DbType = "DateTime", UpdateCheck = UpdateCheck.Never, Expression = "dbo.usrFn_UTCToLocalTime(BirthDate)")]
public System.Nullable<System.DateTime> BirthDate
{
get
{
return this._BirthDate;
}
}
I have also modified the DBML XML as in:
other post on stackoverflow
but also without result.
Is that possible by using LINQ or do I have to overwrite a getter which costs roundtrip to the server?
According to the Remarks section on this MSDN page, the Expression property of the ColumnAttribute is used when calling CreateDatabase, so it won't work the way you intend unless you created your database with Linq to Sql.
You can create a Linq query that selects the various columns and calls the db function in one statement like this (based on MSDN example):
var qry = from person in db.Persons
select new {
FirstName = person.FirstName,
LastName = person.LastName,
BirthDate = person.BirthDate,
Dob = db.usrFn_UTCToLocalTime(person.BirthDate)
};
This projects into an anonymous type, but you could use a non-anonymous type as well. For the sake of the example, I've got a table named Person with FirstName, LastName, and BirthDate columns, and a user defined scalar function named usrFn_UTCToLocalTime. The sql statement sent to the server is:
SELECT [t0].[FirstName], [t0].[LastName], [t0].[BirthDate], CONVERT(DateTime,[dbo].[usrFn_UTCToLocalTime]([t0].[BirthDate])) AS [Dob]
FROM [dbo].[Person] AS [t0]
As I was suggesting in the question, for now I have overwritten the get method so I have:
get
{
using (var context = DB.Data.DataContextFactory.CreateContext())
{
return context.usrFn_UTCToLocalTime(_BirthDate);
}
//return this._BirthDate;
}
But with every access to the property, roundtrip is made - which is not my intention but gives a proper result.
I leave the question still open