I have a number of complex stored procedures using queries containing many table joins, temp data, grouping, sorting etc. So I want to poke in query parameters and return the dataset back from my stored procedure.
If the server code is written in PHP and calls a MYSQL stored procedure, returning JSON, how can I best achieve this using Backbone.js hence the question:
Is it possible to perform non-RESTfull operations using Backbone.js and any code examples please?
You can still just point a Collection / Model to your URL, even if it isn't entirely RESTful. When you call fetch on a Backbone Collection, you can pass in what will eventually be the $.ajax data param:
MyCollection.fetch({data: {page: 3}});
This should make it easier to still use Backbone objects but with the flexibility to work with whatever URL/param structure your PHP endpoints requires.
Related
I have created a view on SQL Server which produces a report for monthly totals. The view has been added to my DB Context and mapped successfully, therefore I am in a position where I can successfully get the results of my view as follows:
var list = db.MonthlyTotals.ToList();
However, I need to be able to restrict between dates and therefore needs to pass in some parameters for a start and end date.
Is this possible with either EF Core 6 or 7? Or do I need to use stored procedures instead?
I have created a view...I need to be able to restrict between dates and therefore needs to pass in some parameters for a start and end date...Is this possible with either EF Core 6 or 7?
Views don't use parameters, that's by design of the SQL Server Engine, and has nothing to do with whatever ORM you use, such as EF Core. If you really want to use parameters, then use stored procedures.
But the good news is, your use case is simple enough that you shouldn't need parameters anyway. Like Gert suggested in the comments, just use a Where clause against your view instead.
You can achieve this in C# with LINQ's method syntax like so:
var list = db.MonthlyTotals
.Where(mt => mt.YourDateColumn >= someDateVariable && my.YourDateColumn < someOtherDateVariable)
.ToList();
There's also query syntax with LINQ, which more closely resembles T-SQL code, but in my opinion is less intuitive in the context of C# as opposed to method syntax.
Background: I have few models which are materialized as 'Table'. This tables are populated with wipe(Truncate) and Load. Now I want to protect my existing data in the Table if the query used to populate data is returning empty result set. How can I make sure an empty result set is not replacing my existing data in table.
My table lies in Snowflake and using dbt to model the output table.
Nutshell: Commit the transaction only when SQL statement used is returning Not empty result set.
Have you tried using dbt ref() function, which allows us to reference one model within another?
https://docs.getdbt.com/reference/dbt-jinja-functions/ref
If you are loading data in a way that is not controlled via dbt and then you are using this table - this is called a source. You can read more about this in here.
dbt does not control what you load into a source, everything else that is the T in the ELT is controlled where you reference a model via ref() function. A great example if you have a source that changes and you load it into a table and make sure that incoming data does not "drop" already recorded data is "incremental" materialization. I suggest you read more in here.
Thinking incremental takes time and practise, also it is recommended every now and then to do a --full-refresh.
You can have pre-hooks and post-hooks that can check your sources with clever macros and add dbt tests. We would really need a little bit more context of what you have and what you wish to achieve to suggest a real response.
I have this query to be executed :
Select * From Products WHERE Title like '%search text%'
ORDER BY Difference(Title, 'search text') DESC
Now I want to implement the above query using EntityFrameworkCore and linq.
So how can I call difference function to order products by closest match in Title column?
Every IQueryable holds an Expression and a Provider. The Expression holds the query that must be performed. The Provider knows who has to execute the query, usually a database management system. It is the task of the Provider to translate the Expression into the language that the database understands (something SQL-like) and to execute the query. The Provider will fetch the results in an efficient way and return the queried data as an enumerable object.
The IQueryable implements IEnumerable.
When you use LINQ functions like ToList(), FirstOrDefault(), Any(), or use the query in a foreach, then internally IEnumerable.GetEnumerator() is called and Enumerator.MoveNext()
This will order the Provider to translate the Expression into SQL and execute the query. The returned enumerable is used to enumerate over the returned items.
It is the task of the programmer of the class that implements the IQueryable to implement the translation of the Expression into SQL. This is not easy, and I think the people who created entity framework did a great job.
However, some items known in SQL are very difficult to implement. Among those are the notions of SoundEx and Difference. I'm not sure, but I think that one of the reasons that made this difficult is that they are typically something used in SQL, and not in any other kind of IQueryable systems.
In fact, there are a several functions that are not supported by entity framework. See Supported and unsupported LINQ methods (LINQ to entities).
Your DbContext is an abstract representation of your database model. Users of it should not care whether it uses Microsoft SQL, MySQL, or whether it is a data collection that doesn't use anything similar to SQL.
But if you are absolutely certain that it is okay to limit your DbContext to only a certain kind of databases, one that knows the concepts of SoundEx and Difference, consider creating a stored procedure for your query. See How to call a Stored Procedure in Entity Framework
SQL can not understand the Difference function written in c#. To make it work you will have to fetch values from Products table in a c# collection like List
Then do ordering on that list using Difference function
I have a table with about 30 fields. I current have several stored procedures which access either a (aggregated) view of this table or the table itself. For many of these SPs I would like to assure that the returned records have all the same fields with the same column names. Is there a way to do this where I don't have to change 20 stored procs if I do need to change the output.
My way around it thus far is to provide clients with lists of ID which they then call SP's that return the data however this seems to be slow compared with getting the data in one shot. I have also considered using the formatting stored procs with a cursor from inside the search stored procs but was unsure if that would really buy me a whole lot.
The typical way to define a standardised and consistent data access method across multiple stored procedures in SQL Server to use Views.
Now your problem description seems to suggest that you are already using Views in order to manage your data access. If you are indeed unable to use Views for a specific reason, perhaps you can clarify the nature of your problem further for us.
When using multivalue parameters in sql reporting services is it more appropriate to implement the list filter using a filter on the dataset itself, the data region control or change the actual query that drives the dataset?
SSRS will support any scenario, so then I ask, is there a reason beyond the obvious of why this should be done at one level over another?
It makes sense to me that modifying the query itself and asking the RDBMS to handle the filtering would be most efficient but maybe I am missing something with respect to how the SSRS Data Processing Extension may handle this scenario?
You are correct. The way to go is to pass the parameters through to the database engine.
Reporting Services should only be ideally used to render content. The less data that you need to pass back to the client web browser, the faster the report will render.
You may find my answer to a similar post regarding using mulit-value parameters to be of use.
Passing multiple values for a single parameter in Reporting Services
Hope this helps but please feel free to pose any further questions you may have.
Cheers,
John
Using table-valued UDF is a good approach, but there is still one issue - in case if this function is called in many places of query, and even inside inner select, there can be performance problem. You can resolve this issue using table variable (or temp table eather):
DECLARE #Param (Value INT)
INSERT INTO #Param (Value)
SELECT Param FROM dbo.fn_MVParam(#sParameterString,',')
...
where someColumn IN(SELECT Value FROM #Param)
so function will be called only once.
Othe thing, if you don't use stored procedure, but embedded SQL query instead, you can just put MVP into query:
...
where someColumn IN(#Param)
...
Use the RDBMS to do the main filtering
SSRS provides filtering for the purposes on data driven display and/or dynamic display. Especially useful for sub reports etc