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now I teaching Spring, and create simple project.
In my program I have User and Ore(Iron, Coal) but i think in future i add new ore or same goods.
And I don't know how implement many column.
If I create 50 different resources, these are 50 fields in the User class, but this is very inconvenient, how can I create such a relationship in the database. So that many resources can be added quickly.
I thought about design patterns, but I don't know which one is better to choose.
The project is built on Spring, PostgreSQL, MVC
You are misunderstanding the concept of a database. You don't add a column for each entry. Instead, look at your items, ores in this case, what do they have in common?
Could be something like
Id, OreName
Or could be somwthing complex like:
Id, OreName, price + a bunch of other columns with relations
It all depends on your requirements. I highly recommend you check out a database design video. Those would help you tremendously.
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I need all reports with all officers included in the participants column.
please check the attached image.
https://prnt.sc/CRoELD48J-L5
You should really have a participant pivot table with report_id and officer_id, and create proper relationships.
What you're asking for is possible through loops and lazy loading, but it will be extremely slow and unoptimized.
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Vendor asks to expose a rest api as odata, trying to understand how it works in odata world, my assumption is the data model present themselves as entities, which then enables filter by query string, but how would a odata query work on a relational data model, e.g. on customer orders, I cannot simply join the entire customer and order table then return the entire dataset! (or maybe I could just return them as paged data?) could someone point out some best practice for designing odata webapis? much appreciated!! thanks!!!
I guess, you are using Entity Framework as a Model for OData.
so
return Ok(myDb.Customers)
would do the trick for a multiple row fetch.
Basically, $expand (JOIN on other tables) and $filter and $select are automagically applied using your whole EF model.
But if you fear that private data or secure data would be exposed, you have to apply prefiltering.
return Ok(myDb.Customers.Where(w => w.CustomerId == myCustomerId))
Odata has built in settings to avoid it to return say, 10.000 rows.
You are quite free configuring that all. But expect some learning curve because after all, you might need extra modelling and navigation property optimization.
In addition, you have by default on an OData controller, GET/POST/PUT/PATCH/DELETE methods, but you also might want custom functions/actions that you have to define.
On Github, Microsoft has quite some samples.
https://github.com/OData/ODataSamples/tree/master/WebApi/v4
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I'm hoping someone might be able to help me. I'm looking at using SSRS to pre-populate fields, and I'd like to have a dropdown list which our staff can select from, when we have them fill out this form online. Is it possible to have a drop down list in one of the tables? Or is it not possible?
I hope this makes sense.
First supposing what you mean by pre-populate fields is let user to insert data into your database tables using some form then show this data in a report.
Reporting Services is not designed to insert or alter data anyway. Instead it is used commonly for reporting purposes, to show data using charts and controls allowing limited user interaction.
If supposition is wrong and you want to add a drop-down list to filter your data or specify presentation conditions you can use a parameter. Go through this technet tutorial where adding and setting for a report parameter is explained.
It is possible to add custom report items to your report, go to this documentation and check this sample in codeplex.
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I've just started working on magento 1.7 recently , and i know how to add categories and product one by one ,but i've large amount of categories and product.Is there any alternative to add large amount of categories in one way?
I've heard about of sample data , is it a solution of my above problem , if it is than how to use that?
Please help me in this matter.
Just noticed this - look into MAGMI for mass importing large amounts of product data into Magento;
http://sourceforge.net/apps/mediawiki/magmi/index.php?title=What_is_magmi
Here's a link to the section on categories;
http://sourceforge.net/apps/mediawiki/magmi/index.php?title=Import_categories
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I need to clone a table of a database which exists in a different servers.
e.g.On server A there is a database called EmployeeDataBase which has a table t1 which I need to copy to the database called EmployeeDataBase which exists on Server B.
How to do it using linq query.
My application uses linq to entity.
Thanks
If the tables have the same definition you can use the same mappings, just you need to create different contexts using the appropriate connection strings.
var ctxSource = new EmployeeDataBaseContext("[source connection]");
var ctxDestination = new EmployeeDataBaseContext("[destination connection]");
ctxDestination.t1.InsertAllOnSubmit(ctxSource.t1.ToList());
ctxDestination.SubmitChanges();
Check here the constructors you need.
Entity Framework is not the right technology for this kind of problem. You will be better off using raw ADO.Net. Maybe SqlBulkCopy can be of use: http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlbulkcopy.aspx