i'm using LinQ .
In SQL Server i can get List of existing Views using :
select * from sys.views
Above query returns :
Views_Email_1
-------------
Views_Email_2
How to do the same using LinQ?
A View is a virtual table based on the result-set of an SQL statement.
Linq Syntax
var viewList = from view in DBContext.sys.Views
select view.Name;
Method Syntax
var viewList = DBContext.sys.Views.Select(x=>x.Name);
Related
Hi I need some help coverting this sql statement to Linq, I am very new to Linq and LinqToSql, and this is my weakness, it seems like this is used frequently and I need to wrap my brain around the syntax. The Code is below.
select distinct t1.Color from [ProductAttributes] t1 join [Product] t2 on t1.Name = t2.ProductName where t1.ProductID = #productID order by t1.color
#productID is the parameter coming into the function, where I am trying to use Linq in MVC.
Thanks
It might be like this I guess
int myProductID = 1;//or whatever id you want.
MyDataContext mdc = new MyDataContext(CONNECTION_STRING_IF_NEEDED);
//MyDataContext is your datacontext generated by LinqToSql
var result = (from x in mdc.ProductAttributes
join y in Products on x.Name.equals(y.ProductName)
where x.ProductID = myProductID
orderby x.color
select x.Color).Distinct();
Note That Table names might need to be fixed.
I have created a view in oracle. Now i would like to fetch data from that view. So i have written a SQL Query. But the query is not working for not having a specific condition. But if I give that condition the query executes. But the problem is not occurring if i joined the same number of tables (that were used to create view) instead of using view. In the following I am giving the oracle query.
SELECT *
FROM "920_search_report"
WHERE lm_culture = '7aacb509-271d-4aca-e040-e00adea40aae'
AND hand_person_info_guid = 'eebd4257-7856-4c6e-b6b8-9b886e89e397'
AND ( Lower(handicap_type) LIKE Lower('%DQ871J%')
OR Lower(skskodenr) LIKE Lower('%DQ871J%') );
The above query executes and returns one record but if I omit or comment the third line then the query does not return any records, but it should return one or two. the query is given below:
SELECT *
FROM "920_search_report"
WHERE lm_culture = '7aacb509-271d-4aca-e040-e00adea40aae'
--AND HAND_PERSON_INFO_GUID='eebd4257-7856-4c6e-b6b8-9b886e89e397'
AND ( Lower(handicap_type) LIKE Lower('%DQ871J%')
OR Lower(skskodenr) LIKE Lower('%DQ871J%') );
Can anyone help me to solve the problem.
I want to filter a DataView but DV.Rowfilter is taking too much time .
dv.RowFilter = "ProductName like '%" + searchtxt + "%'";
So I decided to use the LINQ but how to implement above like query in LINQ ?
LINQ is not more efficient in general, but it can increase readability and maintainability.
So you can try Linq-To-DataSet:
var query = from row in dv.Table.AsEnumerable()
let productName = row.Field<string>("ProductName")
where productName.Contains(searchtxt)
select row;
DataTable tbl = query.CopyToDataTable(); // use this as DataSource or use tbl.DefaultView
Here the same with method syntax:
var query = dv.Table.AsEnumerable()
.Where(row => row.Field<string>("ProductName").Contains(searchtxt));
MSDN: Creating a DataView Object with LINQ to DataSet
i have tried your second solution, but now its throwing the exception
"The source contains no DataRows." and actually the DataTable which i
make as DataTable.AsEnumerable() , it has the rows in it
The table contains rows but the filter skips all of them.
You could use if(query.Any()){...} to check if there are rows:
DataTable tbl = dv.Table.Clone(); // creates an empty table with the same columns
if(query.Any())
tbl = query.CopyToDataTable();
This is my SQL query
SELECT
sys.sysobjects.name Name,
sys.foreign_keys.*
FROM
sys.foreign_keys
inner join sys.sysobjects on
sys.foreign_keys.parent_object_id = sys.sysobjects.id
WHERE
referenced_object_id = OBJECT_ID(N'[dbo].[Country]')
I have installed Linqer to convert SQL to linq.
But I got an error:
SQL cannot be converted to LINQ: Table [foreign_keys] not found in the current Data Context.
I am a beginner in Linq. Can Anyone help me to convert SQL to Linq
The problem is that system views will not be picked up by Linqer. If you want to read these tables in your application, first create your own views on them, as was done here and write a query on these views.
CREATE VIEW SysObjectsView AS SELECT * FROM sys.sysobjects;
GO
CREATE VIEW SysForeignKeysView AS SELECT * FROM sys.foreign_keys;
GO
SELECT obj.name Name, fk.*
FROM SysForeignKeysView fk
INNER JOIN SysObjectsView obj ON fk.parent_object_id = obj.id
INNER JOIN SysObjectsView objfk ON fk.referenced_object_id = objfk.id
WHERE objfk.name = N'Country'
Linqer should be able to pick up these views.
In sql server, we can issue sql to get data like
select * from table where column like '%myword%'
select * from person where Soundex(LastName) = Soundex('Ann')
what's the linq query to match above sql?
from t in table
where t.column.Contains("myword")
select t
In .Net 4.0 you can use the SoundCode function, probably like this:
from p in person
where SqlFunctions.SoundCode(p.LastName) == SqlFunctions.SoundCode('Ann')
select p
you may want to use the difference function
http://msdn.microsoft.com/en-us/library/system.data.objects.sqlclient.sqlfunctions.difference%28VS.100%29.aspx
you could also create your own
https://web.archive.org/web/1/http://blogs.techrepublic%2ecom%2ecom/programming-and-development/?p=656